研究者基本情報

• 疫学修士, ハーバード大学公衆衛生大学院
• 博士（医学）, 東京慈恵会医科大学

• https://researchmap.jp/hiroyosii

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=202001004802991322

• 202001004802991322

研究活動情報

• Empirical antipseudomonal antibiotic therapy and in-hospital mortality in biliary tract infections with bacteremia: a multicenter retrospective cohort study in Japan.
  Koji Endo; Hiroyoshi Iwata; Makoto Kaneko; Keisuke Kamada; Yuki Honda; Yoshito Homma; Takao Wakabayashi; Kenji Kanto; Yuki Nagai; Shuhei Hamada; Takashi Saito; Kyoji Hashimoto; Takuya Aoki
  Infection, 2026年08月21日, ［最終著者］, ［国際誌］
  英語, 研究論文（学術雑誌）, OBJECTIVES: To evaluate the association between the use of empirical antipseudomonal antibiotics and in-hospital mortality in patients with bacteremia due to biliary tract infections. METHODS: We conducted a multicenter retrospective cohort study using data from the JApan Bacteremia Inpatient Cohort Association (JA-BICA), a database of 1105 adult inpatients with bacteremia sourced from eight community general hospitals across Japan. Adult patients with bacteremia due to biliary tract infections were included in this study. Patients who received empirical antipseudomonal antibiotics on the day of hospital admission were categorized into the exposure group and those who did not receive such antibiotics were categorized into the comparison group. The primary outcome measure was the all-cause in-hospital mortality. We evaluated the association between antipseudomonal antibiotic use and in-hospital mortality using cumulative incidence functions and the Fine-Gray subdistribution hazard models with propensity score-based stabilized inverse probability of treatment weighting (IPTW). The missing covariates were addressed using multiple imputations. RESULTS: Among 216 eligible patients, 160 (74.0%) received empirical antipseudomonal antibiotics. IPTW-weighted Fine-Gray analysis showed no detectable association between antipseudomonal antibiotic use and in-hospital mortality (subdistribution hazard ratio, 1.02; 95% CI, 0.4-2.59; P = 0.96). CONCLUSIONS: In the present study, no clear association was observed between empirical antipseudomonal antibiotic therapy and in-hospital mortality in patients with bacteremia due to biliary tract infection; however, the estimate was imprecise due to the limited number of events. These findings highlight the need for further studies to guide empirical antibiotics selection in this population.
• Association between maternal work environment and health-related quality of life during pregnancy using the 8-item short-form health survey (SF-8): the Japan Environment and Children's Study.
  Sumitaka Kobayashi; Yasuaki Saijo; Mariko Itoh; Naomi Tamura; Maki Tojo; Hiroyoshi Iwata; Takeshi Yamaguchi; Yoshiya Ito; Reiko Kishi
  European journal of obstetrics, gynecology, and reproductive biology, 325, 115286, 115286, 2026年07月04日, ［国際誌］
  英語, 研究論文（学術雑誌）, OBJECTIVES: Reports on the association between maternal work environment and health-related quality of life (HR-QOL) during pregnancy are limited. We hypothesized that the work environment in the first trimester would affect HR-QOL in the second/third trimester. Therefore, we examined the association between maternal work environment and HR-QOL among pregnant women. Prospective birth cohort data from the Japan Environment and Children's Study were used. Information on maternal occupational groups, type of employment, working hours, and shift work was obtained using a self-administered questionnaire in the first trimester. Information on HR-QOL was obtained using a self-administered Short-Form Health Survey-8 (SF-8) questionnaires in the second/third trimester. Associations between the maternal work environment and HR-QOL were examined using generalized linear models adjusted for confounding factors. RESULTS: In total, 43,625 pregnant women worked during their first trimester. In the physical component summary (PCS) score, average weekly working hours of ≥ 51 h/week decreased by 0.306 (95% confidence interval: 0.094-0.519). Monthly shift work of ≥ 5 days/month decreased by 0.897 (0.689-1.105). The combination of average weekly working hours of ≥ 51 h/week and monthly shift work of ≥ 5 days/month resulted in a decrease of 1.622 (1.121-2.124). Associations between employment type and PCS scores were also observed. However, the maternal occupational group was not associated with HR-QOL. We found an association between the maternal work environment and HR-QOL. CONCLUSIONS: The change in HR-QOL was meaningful from a public health perspective; however, it was small.
• Impact of prenatal manganese and selenium exposure on childhood thyroid hormone parameters up to 4 years of age: Japan environment and children’s study
  Takeshi Yamaguchi; Hiroyoshi Iwata; Sachiko Itoh; Yu Ait Bamai; Atsuko Ikeda; Keitaro Makino; Mariko Itoh; Rahel Mesfin Ketema; Naomi Tamura; Rieko Yamamoto; Maki Tojo; Kensuke Oba; Shuntaro Morikawa; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  Environment International, 110353, 110353, Elsevier BV, 2026年06月
  研究論文（学術雑誌）
• Medium-term impact of hypertension in pregnancy on subsequent casual and home blood pressures and renal function
  Mami Ishikuro; Taku Obara; Hiroki Nobayashi; Noriyuki Iwama; Keiko Tanaka; Md. Shafiur Rahman; Tomoko Nishimura; Midori Yamamoto; Maki Tojo; Hiroyoshi Iwata; Fumihiro Sata; Atsushi Shimizu; Kazue Ishitsuka; Yoshihiro Miyake; Kenji J. Tsuchiya; Kenichi Sakurai; Chisato Mori; Reiko Kishi; Naho Morisaki; Shinichi Kuriyama; Hirohito Metoki
  Hypertension Research in Pregnancy, 14, 2, 12, 19, Japan Society for the Study of Hypertension in Pregnancy, 2026年05月29日
  研究論文（学術雑誌）
• Relationship between pre-pregnancy body mass index and postpartum depression, and the mediation effects of cesarean delivery, low birth weight, child anomaly, and breastfeeding: a prospective birth cohort in the Japan environment and children’s study
  Yasuaki Saijo; Yukihiro Sato; Hiroyuki Shiotsuki; Tomoki Ishikawa; Eiji Yoshioka; Kentaro Nakanishi; Yasuhito Kato; Ken Nagaya; Satoru Takahashi; Yoshiya Ito; Mariko Itoh; Hiroyoshi Iwata; Takeshi Yamaguchi; Reiko Kishi; Michihiro Kamijima; Shin Yamazaki; Maki Fukami; Chiharu Ota; Koichi Hashimoto; Kenichi Sakurai; Shuichi Ito; Ryoji Shinohara; Hidekuni Inadera; Takeo Nakayama; Ryo Kawasaki; Yasuhiro Takeshima; Hideki Nagashima; Narufumi Suganuma; Mayumi Tsuji; Kimitoshi Nakamura
  BMC Pregnancy and Childbirth, Springer Science and Business Media LLC, 2026年05月27日
  研究論文（学術雑誌）
• The impact of folic acid supplementation in early to mid-pregnancy on the risk of hypertensive disorders of pregnancy: the Japan environment and children’s study
  Akira Oku; Yoshihiro Saito; Hiroyoshi Iwata; Sachiko Itoh; Ami Hosokawa; Takeshi Yamaguchi; Mariko Itoh; Keitaro Makino; Maki Tojo; Hidemichi Watari; Yoshiya Ito; Yasuaki Saijo; Reiko Kishi; Michihiro Kamijima; Shin Yamazaki; Maki Fukami; Reiko Kishi; Chiharu Ota; Koichi Hashimoto; Kenichi Sakurai; Shuichi Ito; Ryoji Shinohara; Hidekuni Inadera; Takeo Nakayama; Ryo Kawasaki; Yasuhiro Takeshima; Hideki Nagashima; Narufumi Suganuma; Mayumi Tsuji; Kimitoshi Nakamura
  BMC Pregnancy and Childbirth, Springer Science and Business Media LLC, 2026年03月06日
  研究論文（学術雑誌）
• Associations of prenatal exposure to organophosphate pesticides with eczema and allergic rhinoconjunctivitis in 4-year-old children: The Japan Environment and Children's Study
  Megasari Marsela; Hiroyoshi Iwata; Yu Ait Bamai; Mariko Itoh; Rahel Mesfin Ketema; Takeshi Yamaguchi; Yasuaki Saijo; Yoshiya Ito; Sachiko Itoh; Keiko Yamazaki; Naomi Tamura; Keitaro Makino; Maki Tojo; Reiko Kishi; Atsuko Ikeda
  Environmental Research, 123839, 123839, Elsevier BV, 2026年02月
  研究論文（学術雑誌）
• Effects of maternal occupation on low birth weight and preterm birth: A prospective birth cohort study in the first trimester, the Japan environment and Children's study.
  Sumitaka Kobayashi; Hiroyoshi Iwata; Takeshi Yamaguchi; Naomi Tamura; Mariko Itoh; Maki Tojo; Keiko Yamazaki; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics, 172, 2, 991, 1008, 2026年02月, ［国際誌］
  英語, 研究論文（学術雑誌）, OBJECTIVE: Although there are some reports that maternal occupation during pregnancy decreases birth size, the results are inconsistent. Hence, we examined the association of maternal occupation during pregnancy with infant low birth weight (LBW) and preterm birth (PB). METHODS: We used data from 53 932 participants of the prospective birth cohort of the Japan Environment and Children's Study. During the first trimester, information on maternal occupational major and minor groups, type of employment, and average weekly working hours was obtained using a self-administered questionnaire. Information on LBW and PB was obtained from medical records transcribed by physicians, midwives/nurses, and/or research coordinators at birth. Associations between maternal occupation and birth outcomes were examined using logistic regression models adjusted for confounding factors. RESULTS: In the major occupational group, the odds ratio (95% confidence interval) of LBW in administrative and managerial workers (0.52; 0.32-0.84) was lower than that in professional and engineering workers. Among administrative and managerial workers, the percentages of LBW among management government officials (4.6%), officers of companies and organizations (4.0%), and management staff of companies and organizations (7.1%) were lower than the overall average of 8.2%. Similar results were found for LBW at full-term (Term-LBW; ≥37 weeks of gestational age). However, there were no associations between the maternal major occupational groups on PB. We observed the association of maternal occupation in the first trimester on infant LBW and Term-LBW. CONCLUSION: The results suggest that medical professionals need to advise considering maternal occupation when performing pregnancy checkups.
• Echinococcosis in Japan: Time to Reconsider a Neglected Endemic.
  Hiroyoshi Iwata; Takeshi Yamaguchi; Keitaro Makino; Reiko Kishi
  Internal medicine (Tokyo, Japan), 2025年12月25日, ［国内誌］
  英語, 研究論文（学術雑誌）
• Early Prediction Model for Antibiotic Treatment Failure in Bacteremia: Japan Bacteremia Inpatient Cohort Association
  Hiroyoshi Iwata; Makoto Kaneko; Keisuke Kamada; Koji Endo; Yuki Honda; Yoshito Homma; Takao Wakabayashi; Kenji Kanto; Yuki Nagai; Shuhei Hamada; Takashi Saito; Takuya Aoki
  Journal of Hospital Infection, Elsevier BV, 2025年12月
  研究論文（学術雑誌）
• Toxic metals and trace elements in maternal blood and urinary tract infection during the first 2 years of life: The Japan Environment and Children's Study.
  Keitaro Makino; Hiroyoshi Iwata; Takeshi Yamaguchi; Atsuko Ikeda; Yu Ait Bamai; Sachiko Itoh; Mariko Itoh; Maki Tojo; Naomi Tamura; Rieko Yamamoto; Rahel Mesfin Ketema; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  The Science of the total environment, 1006, 180895, 180895, Elsevier BV, 2025年12月01日, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Urinary tract infections (UTIs) are common bacterial infections in young children and can lead to long-term renal complications. While established risk factors exist, the effect of prenatal exposure to toxic metals and trace elements on UTI risk remains unclear. We examined the association between maternal blood levels of these elements and UTI risk in early childhood. METHODS: This study is based on a nationwide birth cohort, the Japan Environment and Children's Study (JECS), which obtained data from over 100,000 pregnancies through 15 Regional Centres across Japan. Maternal blood samples were collected during mid-late pregnancy and the concentrations of selenium, manganese, lead, cadmium, and mercury were measured. Child UTI diagnoses during the first 2 years of life were assessed by caregiver questionnaires. Multivariable logistic regression models examined associations between log2-transformed level of metals and trace elements and UTI. RESULTS: Overall, 79,161 mother-child pairs were analyzed. During the first 2 years, 877 (1.1 %) children were diagnosed with UTI. Higher maternal selenium levels were associated with increased UTI risk (Odds ratio for a twofold increase in selenium: 1.58, 95 % CI: 1.06-2.35) after adjusting for covariates. The adjusted odds ratios (95 % CI) of other elements were 0.97 (0.82-1.14) in manganese, 1.01 (0.88-1.15) in lead, 0.94 (0.84-1.05) in cadmium, and 1.02 (0.93-1.11) in mercury. CONCLUSIONS: Elevated maternal selenium levels may increase susceptibility to UTIs during the first 2 years of life. Further studies are needed to investigate long-term effects, including bladder and kidney dysfunction.
• Childhood obesity and DNA methylation in an epigenome-wide association study: findings from the Hokkaido Birth Cohort
  Hiroyoshi Iwata; Chihiro Miyashita; Takeshi Yamaguchi; Atsuko Ikeda; Ryu Miura; Machiko Minatoya; Naomi Tamura; Yu Ait Bamai; Sachiko Itoh; Keiko Yamazaki; Rahel Mesfin Ketema; Mariko Itoh; Maki Tojo; Rieko Yamamoto; Keitaro Makino; Reiko Kishi
  Clinical Epigenetics, Springer Science and Business Media LLC, 2025年12月01日
  研究論文（学術雑誌）
• Stability and variability of Edinburgh Postnatal Depression Scale networks among postpartum women: Insights from the Japan Environment and Children's Study
  Yasuhiko Ebina; Sachiko Ito; Takeshi Yamaguchi; Hiroyoshi Iwata; Reiko Kishi
  Journal of Affective Disorders, 391, 119992, 119992, Elsevier BV, 2025年12月
  研究論文（学術雑誌）
• The impact of pediatric constipation on appendicitis: a prospective birth cohort in the Japan Environment and Children's Study.
  Hiroyoshi Iwata; Takeshi Yamaguchi; Sachiko Itoh; Yu Ait Bamai; Atsuko Ikeda; Keitaro Makino; Mariko Itoh; Maki Tojo; Rieko Yamamoto; Naomi Tamura; Rahel Mesfin Ketema; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  BMC pediatrics, 25, 1, 962, 962, 2025年11月26日, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: This study aimed to examine the association between constipation and appendicitis in children using data from a nationwide birth cohort, the Japan Environment and Children's Study (JECS). METHODS: Data were obtained from 64,772 children and their mothers participating in JECS, which included over 100,000 pregnancies across 15 regional centres in Japan. Pediatric constipation was assessed at age three using the Rome III criteria, while appendicitis cases were identified between ages three to four. Logistic regression analyses, including univariable and multivariable models, were conducted to evaluate associations. Additional analyses were stratified by sex. RESULTS: Among the 64,772 children analyzed, 156 cases of appendicitis were identified between the ages of 3 and 4 years. Logistic regression suggested a possible association between constipation and an increased risk of appendicitis (univariable odds ratio [OR]: 1.38, 95% confidence interval [CI]: 0.87–2.10; multivariable OR: 1.36, 95% CI: 0.86–2.06). Although the associations did not reach statistical significance, the point estimates consistently indicated a trend toward increased risk. CONCLUSION: Although our analyses of children aged 3–4 years did not yield statistically significant associations, the observed trends may suggest a potential link between constipation and appendicitis. These findings should be interpreted only as exploratory, and further studies in different age groups, including older children and adults, are warranted to confirm or refute this possible association. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-025-06263-7.
• Cord Blood Mitochondrial DNA Copy Number and Physical Growth in Infancy and Toddlerhood: A Birth Cohort Analysis.
  Hisanori Fukunaga; Takeshi Yamaguchi; Hiroyoshi Iwata; Atsuko Ikeda
  Children (Basel, Switzerland), 12, 10, 1369, 1369, MDPI AG, 2025年10月10日, ［国際誌］
  英語, 研究論文（学術雑誌）, Background/Objectives: Cord blood mitochondrial DNA copy number (mtDNAcn) has been proposed as a biomarker reflecting environmental influences during fetal life, with reported associations with perinatal outcomes such as birth weight and length. Within the framework of the Developmental Origins of Health and Disease (DOHaD) theory, this study aimed to investigate whether cord blood mtDNAcn is related to postnatal physical growth in early childhood. Methods: We analyzed data from 150 newborns (68 females and 82 males) enrolled in the Tohoku Medical Megabank Birth and Three-Generation Cohort Study in Japan. Cord blood mtDNAcn was quantified using real-time PCR, and standard deviation scores for weight and height were assessed at 1, 2–3, 4–6, 18–24, and 36–48 months of age. Correlation analyses were conducted separately by sex. Results: Cord blood mtDNAcn showed no significant associations with body weight or height at any of the postnatal time points up to 48 months of age. Growth trajectories of infants with higher or lower mtDNAcn values at birth tended to converge toward the population mean during infancy and toddlerhood. Conclusions: Although no significant relationships were observed, this exploratory, hypothesis-generating study provides a foundation for future investigations. Larger cohorts with extended follow-up are needed to clarify the potential significance of cord blood mtDNAcn in early-life research on child growth and health.
• Small for gestational age as a predictor of developmental coordination disorders: Exploring early risk from Japan birth cohort consortium
  Hiroyoshi Iwata; Maki Tojo; Kenji J. Tsuchiya; Mami Ishikuro; Geng Chen; Satoshi Suyama; Akio Nakai; Naomi Tamura; Toshio Yoshikawa; Toyoki Yamagata; Tomoko Nishimura; Takeshi Yamaguchi; Keiko Yamazaki; Taku Obara; Kazue Ishitsuka; Naho Morisaki; Keitaro Makino; Shinichi Kuriyama; Reiko Kishi
  Brain and Development, 47, 5, 104435, 104435, Elsevier BV, 2025年10月
  研究論文（学術雑誌）
• Prediction of Kawasaki disease coronary artery lesions in the Japan Environment and Children’s Study
  Hiroyoshi Iwata; Takeshi Yamaguchi; Naomi Tamura; Yu Ait Bamai; Atsuko Ikeda; Mariko Itoh; Rieko Yamamoto; Maki Tojo; Rahel Mesfin Ketema; Keiko Yamazaki; Sachiko Itoh; Keitaro Makino; Satoru Shida; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  Annals of Pediatric Cardiology, 18, 5, 437, 446, Ovid Technologies (Wolters Kluwer Health), 2025年09月
  研究論文（学術雑誌）, Objective:
  
  This study aimed to validate a composite of previously identified risk factors for predicting coronary artery lesions in Japanese children with Kawasaki Disease (KD).
  
  Materials and Methods:
  
  Children diagnosed with KD from the Japan Environment and Children’s Study (JECS) cohort were included. We assessed the discriminative ability of the model using the area under the curve (AUC) and evaluated its calibration using calibration plots. Based on clinical insights, we derived our original model, which consisted of variables established in previous score models or studies. Using the bootstrap method, internal validation was assessed with the AUC and calibration slope.
  
  Results:
  
  Our analysis included 959 children with KD, derived from 104,062 pediatric records contained in the JECS. Our model comprised the following variables: sex, hematocrit, platelet count, C-reactive protein, and serum sodium levels. The mean and 95% confidence intervals of the AUCs for the Harada, Egami, and Kobayashi models were 0.66 (0.59–0.72), 0.59 (0.52–0.66), and 0.64 (0.56–0.72), respectively. Our score model with bootstrap analyses produced an AUC of 0.80 (0.68–0.91) and a calibration slope of 1.01.
  
  Conclusions:
  
  We built and evaluated our score model using indicators that were easily accessible with a moderate-to-high AUC and stable calibration results, indicating the high reliability of the model for clinical application. Further studies are required to validate our model in other cohorts.
• Association between small for gestational age and neurodevelopmental disability at 5 years in the Hokkaido study
  Satoshi Suyama; Mariko Itoh; Naomi Tamura; Hiroyoshi Iwata; Takeshi Yamaguchi; Sumitaka Kobayashi; Chihiro Miyashita; Takuya Saito; Reiko Kishi
  Pediatrics International, 2025年08月
• Impact of prenatal exposure to per- and polyfluoroalkyl substances on developmental delays in 4-year-old children: The Japan Environment and Children’s study
  Mariko Itoh; Sumitaka Kobayashi; Hiroyoshi Iwata; Yu Ait Bamai; Rahel Mesfin Ketema; Takeshi Yamaguchi; Keiko Yamazaki; Naomi Tamura; Maki Tojo; Satoshi Suyama; Sachiko Itoh; Chihiro Miyashita; Yasuaki Saijo; Yoshiya Ito; Shoji F. Nakayama; Michihiro Kamijima; Reiko Kishi
  Environment International, 198, 109434, 109434, Elsevier BV, 2025年04月
  研究論文（学術雑誌）
• Mediation of prenatal cotinine and 8-hydroxy-2’-deoxyguanosine levels on infant birth size in the Japan Environment and Children’s Study (JECS)
  Sumitaka Kobayashi; Hiroyoshi Iwata; Takeshi Yamaguchi; Naomi Tamura; Mariko Itoh; Maki Tojo; Keiko Yamazaki; Sachiko Itoh; Chihiro Miyashita; Yu Ait Bamai; Yukihiro Sato; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  Reproductive Toxicology, 108905, 108905, Elsevier BV, 2025年04月
  研究論文（学術雑誌）
• Association between prenatal exposure to maternal metal and trace elements and Streptococcus infection: A prospective birth cohort in the Japan Environment and Children’s Study
  Hiroyoshi Iwata; Atsuko Ikeda; Mariko Itoh; Rahel Mesfin Ketema; Naomi Tamura; Takeshi Yamaguchi; Keiko Yamazaki; Rieko Yamamoto; Maki Tojo; Yu Ait Bamai; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  PLOS ONE, 20, 2, e0319356, e0319356, Public Library of Science (PLoS), 2025年02月27日
  研究論文（学術雑誌）, Background
  
  Streptococcus infection is a common and potentially severe bacterial infection which remains a global public health challenge, underscoring the necessity of investigating potential risk factors.
  
  Aims
  
  The present study aims to assess the association between metal and trace element exposure and Streptococcus infection using a prospective nationwide birth cohort, the Japan Environment and Children’s Study (JECS).
  
  Methods
  
  The JECS obtained data from over 100,000 pregnancies through 15 Regional Centres across Japan. We assessed toxic metal and trace element levels among pregnant mothers and Streptococcus infection among their children, born between 2011 and 2014, at age three to four. Analysis was performed using univariable and multivariable logistic regressions, as well as Quantile g-computation. We also conducted quartile regressions to assess the effects of higher serum selenium levels and potential interactions between selenium and mercury.
  
  Results
  
  Among 74,434 infants and their mothers, univariable and multivariable regression analyses found that selenium and mercury each had an inverse association with Streptococcus infection incidence. Quantile g-computation analysis yielded results consistent with the primary regression analyses. Quartile regression suggested that serum selenium levels above the third quartile were inversely associated with later Streptococcus infection incidence, but no interaction between selenium and mercury was found.
  
  Conclusions
  
  These findings imply that maternal selenium exposure may have protective effects on Streptococcus infection among children. Further studies should explore the role of pediatric selenium in immune responses to infectious diseases, especially Streptococcus infection.
• Family history and acquired risk factors for pelvic organ prolapse: a case–control study in Japan
  Asuka Ashikari; Katsumi Kadekawa; Akihiro Tokushige; Hiroyoshi Iwata; Satoko Nagamine; Noriko Machida; Yumi Ikehara; Keiko Mekaru; Junichi Inokuchi; Takeshi Kamiya; Kotaro Nishida; Koshi Nakamura; Shinichiro Ueda; Minoru Miyazato
  Scientific Reports, 15, 1, Springer Science and Business Media LLC, 2025年02月17日
  研究論文（学術雑誌）
• Japanese growth charts stratified by birth weight in 500-gram increments: findings from the Japan environment and children’s study
  Takeshi Yamaguchi; Naomi Tamura; Hiroyoshi Iwata; Sachiko Itoh; Mariko Itoh; Maki Tojo; Keitaro Makino; Yasuaki Saijo; Akie Nakamura; Yoshiya Ito; Kazutoshi Cho; Akinori Moriichi; Yumi Kono; Taro Yamauchi; Reiko Kishi
  Clinical Pediatric Endocrinology, Japanese Society for Pediatric Endocrinology, 2025年
  研究論文（学術雑誌）
• Sick building syndrome, multiple chemical sensitivity, and related factors: A cross-sectional analysis from the Japan Environment and Children's Study.
  Yasuaki Saijo; Eiji Yoshioka; Yukihiro Sato; Hiroyuki Shiotsuki; Kentaro Nakanishi; Yasuhito Kato; Ken Nagaya; Satoru Takahashi; Yoshsiya Ito; Atsuko Ikeda; Hiroyoshi Iwata; Takeshi Yamaguchi; Reiko Kishi
  PloS one, 20, 6, e0324562, 2025年, ［国際誌］
  英語, 研究論文（学術雑誌）, Sick building syndrome (SBS) is caused by having unhealthy indoor environments. Multiple chemical sensitivity (MCS) is a chronic condition that is potentially triggered by low-level chemical exposure. Demographic factors, lifestyle factors, and comorbidities have been reported as potential risk factors of both conditions; however, studies on these factors involving large populations in Japan are limited. The aim of this study was to investigate whether demographics, lifestyle, and comorbidities were associated with MCS and SBS in a large Japanese population, and whether autistic traits (Japanese version of the Autism-Spectrum Quotient Short Form, AQ-10-J), psychological distress (Japanese version of the Kessler 6-Item Psychological Distress Scale, K6), and serum total and allergen-specific immunoglobulin E (IgE) levels were related to the outcomes. The participants included 92,387 pregnant women and 48,451 partners. The outcomes were self-reported physician-diagnosed SBS, MCS, and SBS and/or MCS (combined outcome [CO]). Age-adjusted odds ratios (ORs) of total and antigen-specific IgE levels, demographic factors, and lifestyle factors were determined. The proportions of pregnant women with SBS, MCS, and CO were 307 (0.33%), 128 (0.14%), and 415 (0.45%), respectively, while those of their partners were 85 (0.18%), 30 (0.06%), and 112 (0.23%), respectively. Allergic diseases, psychiatric diseases, migraine, and higher psychological distress were associated with significantly higher ORs for SBS, MCS, and CO. Among pregnant women, autoimmune diseases, cancer, kidney diseases, higher physical activity, autistic traits, and total and specific IgE levels were associated with significantly higher ORs for SBS, MCS, and CO. Clinicians should consider common comorbid disorders when treating patients with SBS and MCS, and their protective and deteriorating lifestyles and demographic factors should be clarified.
• Effects of the maternal work environment on psychological distress during pregnancy: A cross-sectional research-The Japan Environment and Children’s Study
  Sumitaka Kobayashi; Yasuaki Saijo; Mariko Itoh; Naomi Tamura; Maki Tojo; Hiroyoshi Iwata; Takeshi Yamaguchi; Yoshiya Ito; Reiko Kishi
  Journal of Occupational & Environmental Medicine, Ovid Technologies (Wolters Kluwer Health), 2024年11月19日
  研究論文（学術雑誌）, Abstract
  
  Objectives
  
  As part of the “Japan Environment and Children’s Study (JECS),” a national prospective birth cohort study, we examined the association between the maternal work environment and psychological distress during pregnancy in Japan.
  
  Methods
  
  Employing a cross-sectional design, we analyzed data from 42,797 participants, originally collected between 2011 and 2014. Associations between the maternal work environment and psychological distress (Kessler 6) were examined using generalized estimation equation models adjusted for confounding factors.
  
  Results
  
  Pregnant women who worked ≥51 h/week had a 1.19-fold higher odds ratio (OR) of psychological distress than those who worked 36-40 h/week (95% confidence intervals [CI], 1.07-1.32). Pregnant women who worked ≥5 days/month of shift work had a 1.11-fold higher OR of psychological distress than those who worked 0 days/month (1.00-1.24).
  
  Conclusions
  
  We observed an association between the maternal work environment and psychological distress during pregnancy.
• Association between the occupation of pregnant women’s partners and risks of infant low birth weight and preterm birth in a prospective birth cohort: the Japan Environment and Children’s Study
  Sumitaka Kobayashi; Yasuaki Saijo; Hiroyoshi Iwata; Takeshi Yamaguchi; Naomi Tamura; Mariko Itoh; Maki Tojo; Yoshiya Ito; Reiko Kishi
  Journal of Occupational & Environmental Medicine, Ovid Technologies (Wolters Kluwer Health), 2024年11月19日
  研究論文（学術雑誌）, Abstract
  
  Objective
  
  We examined the association between the occupations of pregnant women’s partners and infant low birth weight (LBW) and preterm birth (PB).
  
  Methods
  
  Birth outcome data were collected from 46,540 participants enrolled in the Japan Environment and Children’s Study. Participants were recruited from January 2011 to March 2014. Associations between the occupations of pregnant women’s partners and birth outcomes were examined using logistic regression models adjusted for confounding factors.
  
  Results
  
  LBW and PB incidences were 7.5% and 4.1%, respectively. In the major occupational group, the odds ratios (95% confidence intervals) of LBW for clerical (1.19; 1.03-1.37) and service workers (1.21; 1.05-1.39) were higher than those for professional and engineering workers. However, no associations existed between the major occupational groups of the pregnant women’s partners and PB.
  
  Conclusion
  
  Partner’s employment in clerical and service work increases the risk for LBW.
• Association between small for gestational age and motor coordination difficulties in children aged 5-6 years: Insights from the Hokkaido Study on Environment and Children's Health.
  Maki Tojo; Hiroyoshi Iwata; Naomi Tamura; Takeshi Yamaguchi; Kenji J Tsuchiya; Satoshi Suyama; Taku Obara; Akio Nakai; Toshio Yoshikawa; Toyoki Yamagata; Mariko Itoh; Keiko Yamazaki; Sumitaka Kobayashi; Reiko Kishi
  Brain & development, 47, 1, 104296, 104296, 2024年11月14日, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Developmental coordination disorder (DCD) presents motor skill delays in early childhood and has been associated with later maladaptation, necessitating early intervention. However, research on the potential risk factors, particularly in preschool-aged children, remains scarce. AIMS: We aimed to explore the association between small for gestational age (SGA) and other factors and motor coordination problems in 5-6-year-olds from the Hokkaido Study on Environment and Children's Health Cohort. STUDY DESIGN: Prospective. SUBJECTS: We analyzed data from >3500 participants from the Hokkaido Study, a prospective birth cohort, and assessed children aged 5-6 years. OUTCOME MEASURES: Participants underwent assessment with the Developmental Coordination Disorder Questionnaire Japanese version (DCDQ-J). We conducted linear regression analyses adjusted for variables such as the child's sex, maternal age, and maternal smoking history during pregnancy, while also examining the independent associations of each risk factor. RESULTS: Among the 3883 children analyzed for SGA, children with SGA exhibited significantly lower DCDQ-J total scores than non-SGA children (mean difference: -2.25, 95 % confidence interval [-4.19, -0.30], p = 0.02). On the subscales, children with SGA demonstrated significantly lower "Control During Movement" scores than non-SGA children (mean difference: -0.96, 95 % confidence interval [-1.78, -0.13], p = 0.02). Furthermore, the child's sex, maternal smoking, maternal age, and preterm birth were independently associated with DCD. CONCLUSIONS: SGA was shown to be one of the risk factors for the manifestation of motor coordination difficulties in 5-6-years old children. In combination with other factors, screening for motor coordination difficulties in SGA children will be an important means of initiating appropriate interventions.
• Transforming Large Birth Cohorts and Graduate Education: Challenges and Strategies.
  Hiroyoshi Iwata; Takeshi Yamaguchi; Reiko Kishi
  Internal medicine (Tokyo, Japan), 2024年09月11日, ［国内誌］
  英語, 研究論文（学術雑誌）
• Reasons for encounters, diagnoses, and admission rate among emergency referrals at an urban primary care clinic in Japan: A retrospective cohort study.
  Yoshinao Satoi; Masato Matsushima; Hiroyoshi Iwata
  Journal of general and family medicine, 25, 5, 256, 266, 2024年09月, ［国内誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Comprehensive understanding of emergency referrals (EmR), encompassing reasons for encounters (RFEs) and diagnoses, is crucial for primary care physicians (PCPs). Comparing EmR rates and subsequent admission rates can potentially enhance the quality of primary care for EmR practice. However, no study has evaluated RFEs among patients with EmRs. This study aimed to identify RFE/diagnosis in relation to subsequent admission among patients receiving EmR. METHODS: We conducted a retrospective cohort study at an urban family physician teaching clinic in Kawasaki City, Japan. Our cohort recruited consecutive EmR episodes with their medical records and admissions confirmed through response letters from receiving hospitals. Using the 2nd edition of the International Classification of Primary Care, we explored the frequency of RFEs and diagnoses, calculating EmR rates and admission rates as primary outcomes. Bivariate analyses were employed to compare admission and non-admission cases. RESULTS: The present study encompassed 162 EmR episodes out of 47,901 visits, yielding an EmR rate of 3.38/1000 visits. Among 153 completely followed episodes, 99 patients were emergently admitted, resulting in a 64.7% admission rate. The admission group exhibited significantly higher age and a greater prevalence of dementia. Descriptive analysis revealed fever and pneumonia as the most frequent RFE and diagnosis, respectively, with significant differences between admission and non-admission groups. CONCLUSIONS: The present study reports EmR and admission rates following EmR, highlighting differences in patient characteristics, RFEs, and diagnoses. The findings offer insights to enhance PCPs' EmR practices and serve as a benchmark for the scope of EmR practice.
• Association between maternal multimorbidity and neurodevelopment of offspring: a prospective birth cohort study from the Japan Environment and Children's Study.
  Takanobu Akagi; Yasuaki Saijo; Eiji Yoshioka; Yukihiro Sato; Kentaro Nakanishi; Yasuhito Kato; Ken Nagaya; Satoru Takahashi; Yoshiya Ito; Hiroyoshi Iwata; Takeshi Yamaguchi; Chihiro Miyashita; Sachiko Ito; Reiko Kishi
  BMJ open, 14, 8, e082585, 2024年08月03日, ［国際誌］
  英語, 研究論文（学術雑誌）, OBJECTIVES: To investigate the association between multimorbidity during pregnancy and neurodevelopmental delay in offspring using data from a Japanese nationwide birth cohort study. DESIGN: This study was a prospective birth cohort study. SETTING: This study population included 104 059 fetal records who participated in The Japan Environment and Children's Study from 2011 to 2014. PARTICIPANTS: Pregnant women whose children had undergone developmental testing were included in this analysis. PRIMARY AND SECONDARY OUTCOME MEASURES: Neurodevelopment of offspring was assessed using the Japanese version of the Ages and Stages Questionnaire, third edition, comprising five developmental domains. The number of comorbidities among the pregnant women was categorised as zero, single disease or multimorbidity (two or more diseases). Maternal chronic conditions included in multimorbidity were defined as conditions with high prevalence among women of reproductive age. A multivariate logistic regression analysis was conducted to examine the association between multimorbidity in pregnant women and offspring development. RESULTS: Pregnant women with multimorbidity, single disease and no disease accounted for 3.6%, 30.6% and 65.8%, respectively. The ORs for neurodevelopmental impairment during the follow-up period were similar for infants of mothers with no disease comorbidity and those with a single disease comorbidity. However, the ORs for neurodevelopmental impairment were significantly higher for children born to mothers with multimorbidity compared with those born to healthy mothers. CONCLUSION: An association was observed between the number of comorbidities in pregnant women and developmental delay in offspring. Multimorbidity in pregnant women may be associated with neurodevelopmental delay in their offspring. Further research is required in this regard in many other regions of the world.
• Association between Relative Bradycardia and Adult-onset Still Disease.
  Takao Wakabayashi; Hiroyoshi Iwata
  JMA journal, 7, 3, 426, 430, 2024年07月16日, ［国内誌］
  英語, 研究論文（学術雑誌）
• Correction to: Prenatal metal concentrations and physical abnormalities in the Japan Environment and Children’s Study (Pediatric Research, (2023), 10.1038/s41390-023-02851-4)
  Yuichi Nakamura; Sumitaka Kobayashi; Kazutoshi Cho; Sachiko Itoh; Chihiro Miyashita; Takeshi Yamaguchi; Hiroyoshi Iwata; Naomi Tamura; Yasuaki Saijo; Yoshiya Ito; Yoshitaka Seto; Ryota Honjo; Akiko Ando; Yuta Furuse; Atsushi Manabe; Reiko Kishi; Michihiro Kamijima; Shin Yamazaki; Yukihiro Ohya; Reiko Kishi; Nobuo Yaegashi; Koichi Hashimoto; Chisato Mori; Shuichi Ito; Zentaro Yamagata; Hidekuni Inadera; Takeo Nakayama; Tomotaka Sobue; Masayuki Shima; Hiroshige Nakamura; Narufumi Suganuma; Koichi Kusuhara; Takahiko Katoh
  Pediatric Research, 95, 6, 1659, 1661, 2024年05月
  研究論文（学術雑誌）
• A comparison of opioid dose between home palliative care and hospital palliative care.
  Hiroyoshi Iwata; Shuhei Hamada; Hiroko Harada; Katsuhiro Kusaka
  BMC primary care, 25, 1, 33, 33, 2024年01月23日, ［国際誌］
  英語, 研究論文（学術雑誌）, OBJECTIVE: While opioids are a key part of palliative care, few studies have evaluated opioid demand in the home care context. This study aims to compare opioid usage in home care and hospital care settings. METHODS: This cross-sectional study retrospectively recruited patients receiving palliative care in home care and hospital settings, between November 2018 and October 2020. Opioid prescriptions were standardized to oral morphine equivalent (OME) doses at 7 and 14 days prior to death and analyzed. Additional analysis performed multivariable linear regression on the outcome of OME at 7 days, adjusting for medical setting and confounders in patients with opioid prescriptions. RESULTS: After 21 exclusions, 209 patients (48 home care and 161 hospital care) were eligible for analysis. The home care group had a higher mean age (74.8 years) and Palliative Prognosis Score (50), than the hospital group (70.1 and 40, respectively). Mean OME at 7 and 14 days before death was numerically higher in the home care group (72.8 mg/day and 53.0 mg/day, respectively) than the hospital care group (57.7 mg/day and 35.7 mg/day). Student's t-test produced p-values of 0.49 and 0.32, and the Wilcoxon rank sum test found p-values of 0.24 and 0.11 at 7 and 14 days, respectively. Multivariable regression analysis of the home care group found mean OME of 40.7 mg/day; 95% confidence interval [-0.62, 82.0 (mg/day)], p = 0.06. Additional analysis found a p-value of 0.06 for medical setting. CONCLUSIONS: We did not find a statistically significant difference in opioid use between home care and hospital care. However, the numerically higher rate of use in the home care group suggests that further research is warranted.
• Association between infertility treatment and hypertensive disorders of pregnancy in the Japan Birth Cohort Consortium: a meta-analysis.
  Mami Ishikuro; Tomoko Nishimura; Hiroyoshi Iwata; Hirohito Metoki; Taku Obara; Noriyuki Iwama; Keiko Murakami; Md Shafiur Rahman; Maki Tojo; Sumitaka Kobayashi; Chihiro Miyashita; Keiko Tanaka; Yoshihiro Miyake; Kazue Ishitsuka; Reiko Horikawa; Naho Morisaki; Midori Yamamoto; Kenichi Sakurai; Chisato Mori; Atsushi Shimizu; Fumihiro Sata; Kenji J Tsuchiya; Reiko Kishi; Shinichi Kuriyama
  Journal of human hypertension, 2024年01月10日, ［国際誌］
  英語
• The Population-Attributable Fractions of Small-for-Gestational-Age Births: Results from the Japan Birth Cohort Consortium.
  Kazue Ishitsuka; Aurélie Piedvache; Sumitaka Kobayashi; Noriyuki Iwama; Tomoko Nishimura; Masahiro Watanabe; Hirohito Metoki; Hiroyoshi Iwata; Chihiro Miyashita; Mami Ishikuro; Taku Obara; Kenichi Sakurai; Mohammad Shafiur Rahman; Keiko Tanaka; Yoshihiro Miyake; Reiko Horikawa; Reiko Kishi; Kenji J Tsuchiya; Chisato Mori; Shinichi Kuriyama; Naho Morisaki
  Nutrients, 16, 2, 2024年01月05日, ［国際誌］
  英語, 研究論文（学術雑誌）, A fetal growth restriction is related to adverse child outcomes. We investigated risk ratios and population-attributable fractions (PAF) of small-for-gestational-age (SGA) infants in the Japanese population. Among 28,838 infants from five ongoing prospective birth cohort studies under the Japan Birth Cohort Consortium, two-stage individual-participant data meta-analyses were conducted to calculate risk ratios and PAFs for SGA in advanced maternal age, pre-pregnancy underweight, and smoking and alcohol consumption during pregnancy. Risk ratio was calculated using modified Poisson analyses with robust variance and PAF was calculated in each cohort, following common analyses protocols. Then, results from each cohort study were combined by meta-analyses using random-effects models to obtain the overall estimate for the Japanese population. In this meta-analysis, an increased risk (risk ratio, [95% confidence interval of SGA]) was significantly associated with pre-pregnancy underweight (1.72 [1.42-2.09]), gestational weight gain (1.95 [1.61-2.38]), and continued smoking during pregnancy (1.59 [1.01-2.50]). PAF of underweight, inadequate gestational weight gain, and continued smoking during pregnancy was 10.0% [4.6-15.1%], 31.4% [22.1-39.6%], and 3.2% [-4.8-10.5%], respectively. In conclusion, maternal weight status was a major contributor to SGA births in Japan. Improving maternal weight status should be prioritized to prevent fetal growth restriction.
• Vitamin D concentration in maternal serum during pregnancy: Assessment in Hokkaido in adjunct study of the Japan Environment and Children's Study (JECS).
  Ko Nakanishi; Mami Mutoh; Sachiko Itoh; Sumitaka Kobayashi; Takeshi Yamaguchi; Hiroyoshi Iwata; Naomi Tamura; Momoko Koishi; Machiko Kasai; Emi Kikuchi; Nanae Yasuura; Reiko Kishi; Yoshiaki Sato
  PloS one, 19, 11, e0312516, 2024年, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Vitamin D is an essential nutrient for maintaining blood calcium and phosphorus levels and controlling bone density. Deficiency in it leads to rickets, osteomalacia, osteoporosis, and various other diseases. Recently, it has gained attention for reportedly reducing the risk of COVID-19 severity. However, there are no reports evaluating pregnant women in the Hokkaido region of Japan. This study aims to elucidate the current status of vitamin D levels in pregnant women in the Hokkaido region. METHODS: This study measured the serum concentrations of Vitamin D2 and D3 in 206 pregnant women participating in the Japan Environment and Children's Study-Hokkaido sub-cohort at the Hokkaido Regional Center. It analyzed the relationship between these concentrations and the months, seasons, and sunshine hours. RESULTS: The mean maternal age was 31.7 ± 4.7 years, and the mean prepregnancy BMI was 21.0 ± 2.5 kg/m2. Only two women have given birth at least once. Regarding sunscreen use, 65 participants (31.6%) responded "often" or "sometimes." Five women used the supplement containing Vitamin D. The value of 25(OH)D2 was above 1 ng/ml in four of them. The average 25(OH)D3 level was 12.1 ng/ml, with a median of 11.0 ng/ml. Four participants (1.9%) had levels below 5 ng/ml. The highest median of 25(OH)D3 was in July, and the lowest was in April. The concentration of 25(OH)D3 was significantly higher in summer than in winter. A correlation was found between 25(OH)D3 and sunshine hours, with 25(OH)D3 concentrations gradually increasing as sunshine hours increase. CONCLUSION: It was found that almost all pregnant women in Hokkaido were deficient in vitamin D. It is necessary to implement measures to enhance vitamin D levels in pregnant women to safeguard the health of women and fetuses in Hokkaido.
• Heavy metals and trace elements in maternal blood and prevalence of congenital limb abnormalities among newborns: the Japan Environment and Children's Study.
  Atsuko Ikeda; Megasari Marsela; Chihiro Miyashita; Takeshi Yamaguchi; Yasuaki Saijo; Yoshiya Ito; Hiroyoshi Iwata; Sachiko Itoh; Mariko Itoh; Keiko Yamazaki; Naomi Tamura; Sumitaka Kobayashi; Reiko Kishi
  Environmental health and preventive medicine, 29, 36, 36, 2024年, ［国内誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Heavy metals such as lead (Pb) and cadmium (Cd) have been associated with adverse pregnancy and developmental outcomes, including congenital abnormalities. This study investigated the association between exposure to heavy metals and trace elements during fetal life and congenital limb abnormalities in infants. METHODS: This study is based on a prospective ongoing nationwide birth cohort from the Japan Environment and Children's Study (JECS). The concentrations of Cd, Pb, mercury (Hg), selenium (Se), and manganese (Mn) were measured in maternal blood collected during the mid-late trimesters. Inclusion criteria were available from questionnaires filled in during pregnancy, including information about congenital limb abnormalities at birth or at one month. To examine the associations with limb anomalies and individual chemicals, logistic regression models were applied following log-transformation or division into quartiles of Cd, Pb, Hg, Se, and Mn concentrations. To assess the associations with the heavy metals and trace elements mixture, quantile g-computation was employed. All models were adjusted for age, maternal smoking history, maternal alcohol intake, history of smoking, and infant sex. RESULTS: Data from 90,163 participants were included in the analysis, of whom 369 had congenital limb abnormalities in any of the collected information, and 89,794 had none. Among the 369 cases of congenital limb abnormalities, there were 185 and 142 cases of polydactyly and syndactyly, respectively. The median concentrations of Pb, Cd, Hg, Se, and Mn were 5.85, 0.66, 3.64, 168, and 15.3 ng/g, respectively. There were no associations between maternal blood concentrations of Pb [adjusted odd ratio = 0.83; 95% confidence interval = 0.61, 1.11], Cd [0.87; 0.68, 1.10], Hg [0.88; 0.73, 1.07], Se [1.07; 0.44, 2.59], and Mn [0.91; 0.64, 1.30] with congenital limb abnormalities. No significant association was observed between the mixture of heavy metals and trace elements [0.85; 0.72, 1.02] and any congenital limb abnormalities. Moreover, there was no association with all polydactylies and all syndactylies, or any type of abnormality as a subdivision. CONCLUSION: At the maternal exposure levels of Cd, Pb, Hg, Se, and Mn assessed in the present study, no association was identified with the risk of developing congenital limb abnormalities in children.
• The association between flooring materials and childhood asthma: A prospective birth cohort in the Japan Environment and Children's Study.
  Hiroyoshi Iwata; Atsuko Ikeda; Mariko Itoh; Sachiko Itoh; Rahel Mesfin Ketema; Naomi Tamura; Chihiro Miyashita; Takeshi Yamaguchi; Keiko Yamazaki; Rieko Yamamoto; Maki Tojo; Yasuaki Saijo; Yoshiya Ito; Reiko Kishi
  PloS one, 19, 7, e0305957, 2024年, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Childhood asthma is known to be affected by a range of factors, including conditions in the indoor environment. While flooring material influences indoor air conditions, the potential association between flooring materials and childhood asthma remains poorly understood in Japan. OBJECTIVE: The present study aims to assess the association between childhood asthma incidence and the primary flooring material with the ongoing prospective nationwide birth cohort data of the Japan Environment and Children's Study (JECS). METHODS: The JECS gathered data on mothers and children through 15 Regional Centres across Japan. The present study assessed flooring materials used in the home and asthma incidence at age four among children born between 2011 and 2014. We implemented logistic regressions, setting asthma incidence among the children as the outcome and home floor type as the exposure. Additional analyses were conducted, stratifying the home's age as a proxy for tatami age, to assess whether the potential effect of tatami flooring on asthma risk is influenced by its age. RESULTS: The present study included total of 75,629 infants. For tatami flooring, the main multivariable regression and additional sub-group regression for homes over ten years old produced odds ratios of 1.09; 95% Confidence Interval (CI) [1.01-1.17] and 1.10; 95% CI [1.00-1.21] compared with flooring, respectively. CONCLUSION: These results imply that exposure to tatami flooring, particularly in older homes, may be associated with childhood asthma incidence. Moreover, our study highlights the importance of evaluating the relationship between regional and cultural differences between asthma and flooring materials.
• Maternal pre-pregnancy body mass index and related factors: A cross-sectional analysis from the Japan Environment and Children's Study.
  Yasuaki Saijo; Eiji Yoshioka; Yukihiro Sato; Yuki Kunori; Tomoko Kanaya; Kentaro Nakanishi; Yasuhito Kato; Ken Nagaya; Satoru Takahashi; Yoshiya Ito; Hiroyoshi Iwata; Takeshi Yamaguchi; Chihiro Miyashita; Sachiko Itoh; Reiko Kishi
  PloS one, 19, 6, e0304844, 2024年, ［国際誌］
  英語, 研究論文（学術雑誌）, Socioeconomic status and smoking are reportedly associated with underweight and obesity; however, their associations among pregnant women are unknown. This study aimed to investigate whether socioeconomic factors, namely educational attainment, household income, marital status, and employment status, were associated with pre-pregnancy body mass index (BMI) categories, including severe-moderate underweight (BMI ≤ 16.9 kg/m2), mild underweight (BMI, 17.0-18.4 kg/m2), overweight (BMI, 25.0-29.9 kg/m2), and obese (BMI ≥ 30.0 kg/m2) among Japanese pregnant women using data from the Japan Environment and Children's Study (JECS). In total, pregnant women were included 96,751. Age- and parity-adjusted multivariable multinomial logistic regression analyses assessed socioeconomic factors and smoking associations with falling within abnormal BMI categories (normal BMI as the reference group). Lower education and lower household were associated with overweight and obesity, and, especially, lowest education and household income had relatively higher point estimate relative ratios (RRs) of 3.97 and 2.84, respectively. Regarding the risks for underweight, however, only junior high school education had a significantly higher RR for severely to moderately underweight. Regarding occupational status, homemakers or the unemployed had a higher RR for severe-moderate underweight, overweight, and obesity. Unmarried, divorced, or bereaved women had significantly higher RRs for mildly underweight status. Quitting smoking early in pregnancy/still smoking had higher RRs for all four not having normal BMI outcomes; however, quitting smoking before pregnancy had a higher RR only for obese individuals. Lower educational attainment and smoking are essential intervention targets for obesity and severe-moderate underweight prevention in younger women. Lower household income is also a necessary target for obesity.
• Hokkaido birth cohort study in Japan on the growth trajectory of children born with low birth weight until 7 years of age.
  Kritika Poudel; Sumitaka Kobayashi; Hiroyoshi Iwata; Maki Tojo; Takeshi Yamaguchi; Keiko Yamazaki; Naomi Tamura; Mariko Itoh; Taku Obara; Shinichi Kuriyama; Reiko Kishi
  Early human development, 189, 105925, 105925, 2023年12月26日, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Low birth weight (LBW) is a significant global health concern with potential health risks and developmental implications for infants. Catch-up growth, an accelerated growth following an inhibition period, may partially compensate for growth deficits in LBW children. AIMS: This study investigated the prevalence of LBW and catch-up growth in height, weight, and body mass index (BMI) among LBW children in Japan, identified factors associated with LBW, and explored the potential for catch-up growth at different ages up to seven years. STUDY DESIGN AND SUBJECTS: The Hokkaido birth cohort study included 20,926 pregnant Japanese women recruited during their first trimester from 37 hospitals and clinics. Follow-up assessments were conducted in children up to seven years of age, tracking LBW children's growth and development using the Maternal and Child Health Handbook, and providing valuable insights into catch-up growth patterns. OUTCOME MEASURES: LBW was defined as a neonatal birth weight of <2500 g. The primary outcomes were catch-up growth in height, weight, and BMI at different ages. Z-scores were calculated to assess growth parameters with catch-up growth, defined as a change in z-score (> 0.67) between two time points. RESULTS AND CONCLUSIONS: A LBW was prevalent in 7.6 % of the cohort, which was lower than that reported in other Japanese studies. Among LBW children, 19.3 % achieved catch-up growth in height by age seven, and 10.6 % in weight. Catch-up growth in LBW children could partially offset these deficits. Further research will help understand the long-term outcomes and inform interventions for healthy development.
• The association between prenatal per-and polyfluoroalkyl substance levels and Kawasaki disease among children of up to 4 years of age: A prospective birth cohort of the Japan Environment and Children's study.
  Hiroyoshi Iwata; Sumitaka Kobayashi; Mariko Itoh; Sachiko Itoh; Rahel Mesfin Ketema; Naomi Tamura; Chihiro Miyashita; Takeshi Yamaguchi; Keiko Yamazaki; Hideyuki Masuda; Yu Ait Bamai; Yasuaki Saijo; Yoshiya Ito; Shoji F Nakayama; Michihiro Kamijima; Reiko Kishi
  Environment international, 183, 108321, 108321, 2023年11月11日, ［国際誌］
  英語, 研究論文（学術雑誌）, Kawasaki disease (KD) is common among pediatric patients and is associated with an increased risk of later cardiovascular complications, though the precise pathophysiology of KD remains unknown. Per- and polyfluoroalkyl substances (PFAS) have gathered notoriety as the causal pathogens of numerous diseases as well as for their immunosuppressive effects. The present epidemiological study aims to assess whether PFAS may affect KD risk. We evaluated research participants included in the ongoing prospective nationwide birth cohort of the Japan Environment and Children's Study (JECS). Among the over 100,000 pregnant women enrolled in the JECS study, 28 types of PFAS were measured in pregnancy in a subset of participants (N = 25,040). The JECS followed their children born between 2011 and 2014 (n total infants = 25,256; n Kawasaki disease infants = 271), up to age four. Among the 28 types of PFAS, those which were detected in >60 % of participants at levels above the method reporting limit (MRL) were eligible for analyses. Multivariable logistic regressions were implemented on the seven eligible PFAS, adjusting for multiple comparison effects. Finally, we conducted Weighted Quantile Sum (WQS) and Bayesian kernel machine regression (BKMR) to assess the effects of the PFAS mixture on KD. Therefore, we ran the BKMR model using kernel mechanical regression equations to examine PFAS exposure and the outcomes of KD. Upon analysis, the adjusted multivariable regression results did not reach statistical significance for the seven eligible substances on KD, while odds ratios were all under 1.0. WQS regression was used to estimate the mixture effect of the seven eligible PFAS, revealing a negative correlation with KD incidence; similarly, BKMR implied an inverse association between the PFAS mixture effect and KD incidence. In conclusion, PFAS exposure was not associated with increased KD incidence.
• Prenatal metal concentrations and physical abnormalities in the Japan Environment and Children's Study.
  Yuichi Nakamura; Sumitaka Kobayashi; Kazutoshi Cho; Sachiko Itoh; Chihiro Miyashita; Takeshi Yamaguchi; Hiroyoshi Iwata; Naomi Tamura; Yasuaki Saijo; Yoshiya Ito; Yoshitaka Seto; Ryota Honjo; Akiko Ando; Yuta Furuse; Atsushi Manabe; Reiko Kishi
  Pediatric research, 2023年10月19日, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: The association between prenatal metal exposure and congenital anomalies is unclear. We aimed to examine the association between exposure to cadmium, lead, mercury, selenium, and manganese and physical abnormalities. METHODS: Data from 89,887 pregnant women with singleton pregnancies who participated in the Japan Environment and Children's Study (JECS) were used. The correlation between maternal blood metal concentrations and physical abnormalities during the second or third trimester was investigated using logistic regression models. Physical anomalies included those observed at birth or at 1 month, primarily from ICD-10 Chapter 17, particularly congenital anomalies associated with environmental factors (e.g., hypospadias, cryptorchidism, cleft lip and palate, digestive tract atresia, congenital heart disease, and chromosomal abnormalities) and minor abnormalities. RESULTS: After adjusting for covariates, the OR (95% CIs) of physical abnormalities for a one-unit rise in Mn concentrations in all individuals were 1.26 (1.08, 1.48). The OR (95% CIs) of physical abnormalities in the 4th quartile (≥18.7 ng/g) were 1.06 (1.01, 1.13) (p-value for the trend = 0.034) compared with those in the 1st quartile (≤12.5 ng/g). CONCLUSION: In Japan, maternal blood Mn concentrations above threshold during pregnancy may slightly increase the incidence of physical abnormalities. IMPACT: Physical abnormalities (including minor anomalies and congenital anomalies) are associated with prenatal manganese concentrations. They are not associated with cadmium, lead, mercury, and selenium concentrations.
• Iliac vein compression syndrome induced by giant left common iliac artery aneurysm
  Takao Wakabayashi; Hiroyoshi Iwata
  JOURNAL OF HOSPITAL GENERAL MEDICINE, 5, 5, 2023年09月, ［査読有り］
• Essential components of a definition for early antibiotic treatment failure: A scoping review.
  Hiroyoshi Iwata; Makoto Kaneko; Takuya Aoki; Koji Endo; Yuki Nagai; Kenji Kanto; Masahiro Yao; Shuhei Hamada
  PloS one, 18, 6, e0283417, 2023年, ［査読有り］, ［筆頭著者, 責任著者］, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Despite the broad global use of antibiotics, there is no established definition of early antibiotic treatment failure (EATF) to aid clinical evaluation of treatment, which leads to inconsistent assessments of drug effectiveness. AIM: This scoping review aims to identify common components of EATF definitions by synthesizing studies mentioning EATF and its relevant thesaurus matches. DESIGN: Scoping review. METHODS: This scoping review was conducted following the PRISMA Scoping review guidelines. A systematic literature search was conducted using MEDLINE (PubMed), CENTRAL, CINAHL, and Web of Science, as well as a manual Google search. Search terms were EATF and its thesaurus matches. After removing duplications, candidate studies were screened by title and abstract prior to full text searches, and quality analysis was performed on eligible studies using the Critical Appraisal Skills Programme. From each eligible study, the timing of evaluation, basic components, and detailed information for each definition of EATF were collected. The components of each definition for EATF were then summarized and counted, and finally the most common essential components were identified. RESULTS: Our systematic literature search found 2,472 candidate studies. After title and abstract screening, full text search and quality assessment, 61 studies, including 56 original studies and five reviews, were eligible for our analysis. Of these 56 original studies, 43 mentioned the timing of EATF evaluation 72 hours after the start of treatment with antibiotics. From these 43 studies, the most common indicators of EATF were extracted, among which a set of essential components for a definition of EATF were identified: mortality, vital signs, fever, symptoms, and additional treatment. CONCLUSIONS: Our scoping review uncovered five essential factors for EATF. Further study is needed to evaluate the validity of our findings.
• The dawn of directed acyclic graphs in primary care research and education
  Hiroyoshi Iwata; Takao Wakabayashi; Rika Kato
  Journal of General and Family Medicine, 2023年, ［査読有り］
• The Clinical Utility of Relative Bradycardia for Identifying Cases of Coronavirus Disease 2019 Pneumonia: A Retrospective Pneumonia Cohort Study
  Takao Wakabayashi; Hiroyoshi Iwata
  Internal Medicine, Japanese Society of Internal Medicine, 2023年, ［査読有り］, ［最終著者］
  研究論文（学術雑誌）
• Effect of voluntary human mobility restrictions on vector-borne diseases during the COVID-19 pandemic in Japan: A descriptive epidemiological study using a national database (2016 to 2021).
  Kenji Hibiya; Akira Shinzato; Hiroyoshi Iwata; Takeshi Kinjo; Masao Tateyama; Kazuko Yamamoto; Jiro Fujita
  PloS one, 18, 5, e0285107, 2023年, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, The coronavirus disease 2019 (COVID-19) pandemic not only encouraged people to practice good hygiene but also caused behavioral inhibitions and resulted reduction in both endemic and imported infectious diseases. However, the changing patterns of vector-borne diseases under human mobility restrictions remain unclear. Hence, we aimed to investigate the impact of transborder and local mobility restrictions on vector-borne diseases through a descriptive epidemiological study. The analysis was conducted using data from the National Epidemiological Surveillance of Infectious Diseases system in Japan. We defined the pre-pandemic period as the period between the 1st week of 2016 to the 52nd week of 2019 and defined the pandemic period as from the 1st week of 2020 to the 52nd week of 2021, with the assumption that human mobility was limited throughout the pandemic period. This study addressed 24 diseases among notifiable vector borne diseases. Datasets were obtained from weekly reports from the National Epidemiological Surveillance of Infectious Diseases, and the incidence of each vector-borne disease was examined. Interrupted time series analysis was conducted on the epidemic curves for the two periods. Between the pre- and post-pandemic periods, the incidence of dengue fever and malaria significantly decreased, which may be related to limited human transboundary mobility (p = 0.003/0.002). The incidence of severe fever with thrombocytopenia syndrome, scrub typhus, and Japanese spotted fever did not show changes between the two periods or no association with human mobility. This study suggests that behavioral control may reduce the incidence of new mosquito-borne diseases from endemic areas but may not affect tick-borne disease epidemics within an endemic area.
• Embedding Research Culture in Community Hospitals.
  Hiroyoshi Iwata; Makoto Kaneko; Takao Wakabayashi; Shinichiro Ueda
  Internal medicine (Tokyo, Japan), 61, 20, 3155, 3155, 2022年10月15日, ［査読有り］, ［筆頭著者, 責任著者］, ［国内誌］
  英語, 研究論文（学術雑誌）
• Effect of favorite music on heart rate variability regardless of aging
  Sumiko Satake; Yoshifumi Sugiyama; Rieko Mutai; Hiroyoshi Iwata; Masato Matsushima; Naofumi Kimura
  69, 3, 43, 54, 2022年09月, ［査読有り］
• Duration of the untreated period affects bone mineral density in psychiatric patients requiring long‐term hospitalization: A cross‐sectional study
  Itsuka Kaga; Hiroyoshi Iwata; Akihiro Tokushige; Takushiro Akata; Shinichiro Ueda
  Psychiatry and Clinical Neurosciences Reports, 1, 3, Wiley, 2022年09月, ［査読有り］
  研究論文（学術雑誌）
• The Clinical Significance of Otolaryngology Manifestations in COVID-19 Pneumonia: A Single-center Retrospective Cohort Study.
  Hiroyoshi Iwata; Takao Wakabayashi; Natsuko Inazawa
  Internal medicine (Tokyo, Japan), 2022年08月30日, ［査読有り］, ［筆頭著者, 責任著者］, ［国内誌］
  英語, 研究論文（学術雑誌）, Objective Although the absence of a runny nose and sore throat, both ear-nose-throat (ENT) symptoms, suggests community-acquired pneumonia (CAP), the association between ENT symptoms and coronavirus disease 2019 (COVID-19) pneumonia remains unclear. We therefore investigated the association between ENT symptoms and COVID-19 pneumonia. Methods We retrospectively recruited consecutive confirmed COVID-19 inpatients with and without pneumonia admitted to a single institution from April 1, 2020, to July 31, 2021. After a descriptive analysis, we implemented univariable and multivariable regression analyses to assess the association between ENT symptoms and COVID-19 pneumonia. Results The present study included 385 patients. Pneumonia patients exhibited lower rates of positive runny nose and sore throat than non-pneumonia patients. Univariable analyses found mean odds ratios of 0.59 and 0.61 and 95% confidence intervals (CIs) of 0.30-1.16 and 0.32-1.17 for runny nose and sore throat, respectively, and multivariable analyses found mean odds ratios of 0.73 and 0.70 and 95% CIs of 0.34-1.56 and 0.34-1.46, respectively. Conclusions Our study found no statistically significant association between ENT symptoms and COVID-19 pneumonia. Clinicians should be aware that, unlike CAP, there is no correlation between ENT symptoms and pneumonia among patients with COVID-19, so it is necessary to consider the possibility of pneumonia even in the presence of ENT symptoms.
• The clinical value of hepatojugular reflux on congestive heart failure: A meta‐analysis
  Hiroyoshi Iwata; Yoshikazu Miwa; Yumi Ikehara; Toshifumi Yodoshi; Shinichiro Ueda
  Journal of General and Family Medicine, 23, 6, 393, 400, Wiley, 2022年08月19日, ［査読有り］, ［筆頭著者, 責任著者］, ［国内誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Hepatojugular reflux is a cardiac physical examination with a long history of use in heart failure diagnosis across many clinical settings. However, the development of new diagnostic methods has thrown the clinical role of hepatojugular reflux into question. Our meta-analysis aimed to determine the diagnostic accuracy of hepatojugular reflux and assess its usefulness in diagnosing congestive heart failure among at-risk patients. METHODS: This meta-analysis of studies reporting diagnostic hepatojugular reflux values of patients at risk for congestive heart failure followed PRISMA guidelines. We searched MEDLINE, EMBASE, Web of Science, CENTRAL, and Google Scholar for eligible studies from inception through February 1, 2021. After QUADAS-2 quality assessment, we conducted data synthesis using the random effects model and a hierarchical summary receiver operating characteristic model. As an additional analysis, we sorted the studies by clinical setting and performed synthesis again. We submitted our protocol to PROSPERO (International Prospective Register of Systematic Reviews; ID No. CRD42020215004). RESULTS: The literature search provided 4121 studies for evaluation. Seven studies and their 5195 participants were deemed eligible for synthesis. Clinical diagnosis was the most frequent reference standard. Bivariate random-effects analysis found hepatojugular reflux sensitivity of 0.12, 95% confidence interval (CI) [0.07-0.19], and specificity of 0.96, 95% CI [0.95-0.97]. The DOR was 29.7, 95% CI [18.4-45.3]. The additional analysis of the emergency settings provided a sensitivity of 0.14, 95% CI [0.12-0.17] and specificity of 0.95, 95% CI [0.93-0.96]. CONCLUSIONS: Our meta-analysis suggests that hepatojugular reflux has practical value for diagnosis of congestive heart failure with high specificity.
• Diagnostic accuracy of pelvic examination in pelvic inflammatory disease: A meta‐analysis
  Hiroyoshi Iwata; Yoshifumi Sugiyama; Yoshinao Satoi; Naoko Sasamoto; Takuya Aoki; Masato Matsushima
  Journal of General and Family Medicine, 23, 6, 384, 392, Wiley, 2022年08月03日, ［査読有り］, ［筆頭著者, 責任著者］
  研究論文（学術雑誌）
• Evaluation of the Influence of a History of Childhood Nocturnal Enuresis on Nighttime Urinary Frequency and the Causes of Nocturia in Adults.
  Minoru Miyazato; Munehisa Gakiya; Asuka Ashikari; Tadanobu Chuyo Kamijo; Haruo Kagawa; Tomohiro Matsuo; Yasuyoshi Miyata; Yoshinori Oshiro; Koji Arai; Noriko Machida; Hiroshi Shinzato; Yoshiaki Chinen; Hiroyoshi Iwata; Shinichiro Ueda; Seiichi Saito
  Urology, 164, 106, 111, 2022年06月, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, OBJECTIVE: To examine whether a history of nocturnal enuresis affects nighttime urinary frequency and to evaluate nocturia etiologies in adults. MATERIALS AND METHODS: A total of 143 participants with at least one episode of nocturia per night were included in this study. The self-reported questionnaire collected data on demographic characteristics, medical history, history of nocturnal enuresis in elementary school, lower urinary tract symptoms, and frequency-volume charts. RESULTS: A history of nocturnal enuresis was observed in 52.4% of participants. However, night-time urinary frequency was significantly lower in participants with a history of nocturnal enuresis in elementary school than in those without such history. On multivariate analysis, a history of nocturnal enuresis was also negatively associated with nighttime urinary frequency (P <.01). There was a collinearity effect between age and nighttime urinary frequency. A history of nocturnal enuresis did not affect the presence of nocturnal polyuria or overactive bladder in participants. However, sleep disturbances were fewer in participants with a history of nocturnal enuresis (odds ratio 0.404). CONCLUSION: A history of nocturnal enuresis might be negatively associated with nighttime urinary frequency due to fewer sleep disturbances. Further, progression of nocturia may depend on conditions, such as age and acquired diseases.
• Incidence of common infectious diseases in Japan during the COVID-19 pandemic.
  Kenji Hibiya; Hiroyoshi Iwata; Takeshi Kinjo; Akira Shinzato; Masao Tateyama; Shinichiro Ueda; Jiro Fujita
  PloS one, 17, 1, e0261332, 2022年, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, Recent reports indicate that respiratory infectious diseases were suppressed during the novel coronavirus disease-2019 (COVID-19) pandemic. COVID-19 led to behavioral changes aimed to control droplet transmission or contact transmission. In this study, we examined the incidence of common infectious diseases in Japan during the COVID-19 pandemic. COVID-19 data were extracted from the national data based on the National Epidemiological Surveillance of Infectious Diseases (NESID). Common infectious diseases were selected from notifiable infectious diseases under the NESID. The epidemic activity of the diseases during 2015-2020 was evaluated based on the Infectious Disease Weekly Reports published by the National Institute of Infectious Diseases. Each disease was then categorized according to the route of transmission. Many Japanese people had adopted hygienic activities, such as wearing masks and hand washing, even before the COVID-19 pandemic. We examined the correlation between the time-series of disease counts of common infectious diseases and COVID-19 over time using cross-correlation analysis. The weekly number of cases of measles, rotavirus, and several infections transmitted by droplet spread, was negatively correlated with the weekly number of cases of COVID-19 for up to 20 weeks in the past. According to the difference-in-differences analysis, the activity of influenza and rubella was significantly lower starting from the second week in 2020 than that in 2015-2019. Only legionellosis was more frequent throughout the year than in 2015-2019. Lower activity was also observed in some contact transmitted, airborne-transmitted, and fecal-oral transmitted diseases. However, carbapenem-resistant Enterobacteriaceae, exanthema subitum, showed the same trend as that over the previous 5 years. In conclusion, our study shows that public health interventions for the COVID-19 pandemic may have effectively prevented the transmission of most droplet-transmitted diseases and those transmitted through other routes.
• Development of the Adapted Physician Centrality Scale: a cross-sectional study in Japan (Original)
  Ryoko Horiguchi, Rieko Mutai, Miharu Gomi, Yoshifumi Sugiyama, Hiroyoshi Iwata, Sumiko Satake, Yoshinao Satoi, Keisuke Iwabuchi, Daichi Hayashi, Tadashi Nakano, Masato Matsushima
  68, 4, 89, 98, 2021年12月10日, ［査読有り］
  英語, 研究論文（学術雑誌）
• Outcome, diagnosis, and microbiological profile comparison of community- and hospital-acquired bacteremia: A retrospective cohort study.
  Takao Wakabayashi; Hiroyoshi Iwata
  Journal of general and family medicine, 22, 6, 327, 333, 2021年11月, ［査読有り］, ［最終著者］, ［国内誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Although bacteremia is one of the most pressing situation in the field of hospital medicine, little is known about the differences between community- and hospital-acquired bacteremia (CAB and HAB, respectively). METHODS: Objective is to know the epidemiologic characteristics of CAB and HAB. Study design is a single-center retrospective cohort study. Participants were all patients over the age of 16 years who were blood cultures positive at single acute care hospital from April 2013 to March 2018. HAB was defined as positive culture acquired at least 48 h after admission or blood culture-positive patients transferred from other hospital. The primary outcome was 30 day mortality, and the secondary outcome was 1 year mortality. We compared the primary and secondary outcomes between HAB and CAB using logistic regression analyses. RESULTS: There were 325 participants in this study. The number of patients with CAB was 189 (58.1%). HAB was associated with a higher 30 day mortality rate than CAB (n = 31, 22.8% vs. n = 9, 4.8%, adjusted odds ratio (AOR) 2.60; 95% confidence interval (CI) 1.04-6.53, p < 0.05). In the secondary outcome, HAB was also associated with a higher 1 year mortality rate (n = 61/110, 55.5% vs. n = 32/143, 22.4%, AOR 2.27; 95% CI: 1.12-4.58). CONCLUSIONS: Our study showed that HAB was associated with higher mortality than CAB in 30 day mortality and in 1 yr mortality. Thus, we confirmed that HAB is distinct from CAB concerning the differences of outcomes.
• Skin pigmentation with pellagra.
  Wakabayashi T; Iwata H; Tsuji Y.
  J Hosp Gen Med., 3, 5, 179, 180, 2021年09月
  英語, 研究論文（学術雑誌）
• The need for home care physicians in Japan - 2020 to 2060.
  Hiroyoshi Iwata; Masato Matsushima; Takamasa Watanabe; Yoshifumi Sugiyama; Kenichi Yokobayashi; Daisuke Son; Yoshinao Satoi; Eriko Yoshida; Sumiko Satake; Yuki Hinata; Yasuki Fujinuma
  BMC health services research, 20, 1, 752, 752, 2020年08月15日, ［査読有り］, ［筆頭著者, 責任著者］, ［国際誌］
  英語, 研究論文（学術雑誌）, BACKGROUND: Japan faces the most elderly society in the world, and the Japanese government has launched an unprecedented health plan to reinforce home care medicine and increase the number of home care physicians, which means that an understanding of future needs for geriatric home care is vital. However, little is known about the future need for home care physicians. We attempted to estimate the basic need for home care physicians from 2020 to 2060. METHODS: Our estimation is based on modification of major health work force analysis methods using previously reported official data. Two models were developed to estimate the necessary number of full-time equivalent (FTE) home care physicians: one based on home care patient mortality, the other using physician-to-patient ratio, working with estimated numbers of home and nursing home deaths from 2020 to 2060. Moreover, the final process considered and adjusted for future changes in the proportion of patients dying at home. Lastly, we converted estimated FTE physicians to an estimated head count. RESULTS: Results were concordant between our two models. In every instance, there was overlap of high- and low-estimations between the mortality method and the physician-to-patient method, and the estimates show highly similar patterns. Furthermore, our estimation is supported by the current number of physicians, which was calculated using a different method. Approximately 1.7 times (1.6 by head count) the current number of FTE home care physicians will be needed in Japan in the late 2030's, peaking at 33,500 FTE (71,500 head count). However, the need for home care physicians is anticipated to begin decreasing by 2040. CONCLUSION: The results indicate that the importance of home care physicians will rise with the growing elderly population, and that improvements in home care could partially suppress future need for physicians. After the late 2030's, the supply can be reduced gradually, accounting for the decreasing total number of deaths after 2040. In order to provide sufficient home care and terminal care at home, increasing the number of home care physicians is indispensable. However, the unregulated supply of home care physicians will require careful attention in the future.
• D-dimer level and outcome of minor ischemic stroke with large vessel occlusion.
  Takeo Sato; Shoichiro Sato; Hiroshi Yamagami; Teppei Komatsu; Tadataka Mizoguchi; Takeshi Yoshimoto; Masahito Takagi; Masafumi Ihara; Masatoshi Koga; Hiroyoshi Iwata; Masato Matsushima; Kazunori Toyoda; Yasuyuki Iguchi
  Journal of the neurological sciences, 413, 116814, 116814, 2020年06月15日, ［査読有り］, ［国際誌］
  英語, 研究論文（学術雑誌）, OBJECTIVE: To determine the predictors of unfavorable outcomes in acute minor ischemic stroke patients with large vessel occlusion. METHODS: The derivation cohort included ischemic stroke patients admitted to a comprehensive stroke center within 7 days after onset with large vessel occlusion and an initial National Institutes of Health Stroke Scale score of 5 or less. An unfavorable outcome was defined as dependency (modified Rankin Scale score of 3 to 6) at 3 months from the onset. The predictive values of factors related to an unfavorable outcome were evaluated. External validation was performed from a stroke registry of a tertiary medical center. RESULTS: In the derivation cohort, 3839 consecutive patients were screened; a total of 130 patients were included. Twenty-four (18%) patients had unfavorable outcomes. In multivariate analysis, D-dimer ≥1900 μg/l (odds ratio (OR) 3.31, 95% confidence interval (CI) 1.14-9.61, p = .028) and age (OR 2.01, 95% CI 1.05-3.86, p = .035) were independently associated with an unfavorable outcome. No significant differences were observed regarding occluded vessel sites. In the validation cohort, 850 consecutive patients were screened; a total of 74 patients were included. D-dimer ≥1900 μg/l (OR 8.78, 95% CI 1.41-54.61, p = .020) was the only factor independently associated with an unfavorable outcome, as in the derivation cohort. CONCLUSIONS: A high D-dimer level on admission could help predict unfavorable outcomes in patients with a minor ischemic stroke with large vessel occlusion.
• Excessive dynamic airway collapse
  Hiroyoshi iwata; Katsuhiro Kusaka; Sugihiro Hamaguchi
  BMJ, 356:j601, 2017年02月23日, ［査読有り］, ［筆頭著者, 責任著者］
  英語, 研究論文（学術雑誌）
• An unusual cause of spontaneous bacterial peritonitis due to Campylobacter fetus with alcoholic liver cirrhosis
  Y. Hadano; H. Iwata
  Case Reports, 2013, feb14 1, bcr2012008406, bcr2012008406, BMJ, 2013年02月14日, ［査読有り］, ［最終著者］
  研究論文（学術雑誌）
• Septic thrombophlebitis of the superior mesenteric vein with bacteraemia caused by Bacteroides fragilis and Streptococcus intermedius as a complication of diverculitis
  Y. Hadano; H. Iwata
  Case Reports, 2013, feb05 1, bcr2013008661, bcr2013008661, BMJ, 2013年02月05日, ［査読有り］, ［最終著者］
  研究論文（学術雑誌）
• 総合医が病棟で経験したリチウム中毒の1例
  若林 崇雄; 宮田 靖志; 阿部 昌彦; 濱田 修平; 岩田 啓芳; 山本 和利
  家庭医療, 15, 1, 26, 30, (NPO)日本家庭医療学会, 2009年06月
  日本語, 87歳女。80歳過ぎより認知症、双極性障害と診断され精神科に通院し、炭酸リチウムの処方を受けていた。また、循環器科よりアムロジピン、ロサルタン、トリクロルメチアジドの処方を受けていた。食欲不振が進行、この頃より手の震えを自覚したため、食欲不振の精査目的に入院した。診察所見や検査所見より肺癌の悪化により悪液質が進展し摂食障害が生じたと考えられた。嚥下訓練などによる対応を行ったが食事摂取できなかったため、脱水の改善を目的に補液を行った。しかし、徐脈や神経症状といった身体所見が改善しなかったため、炭酸リチウムによる薬剤性の洞不全症候群を考え、炭酸リチウムを中止した。また、脱水と電解質異常を考慮しトリクロルメチアジドを中止した。炭酸リチウムの血中濃度は中毒域であった。心電図上の補充調律は薬剤中止後改善し洞調律に回復した。また、心電図変化が改善するにつれて振戦ミオクローヌスも改善し、食欲も回復した。

• 菌血症における比較的徐脈の記述及び臨床的意義の検討 多施設後方視的コホート研究
  若林崇雄; 岩田啓芳; 金子惇; 遠藤功二; 本田優希; 本間義人; 鎌田啓佑; 濱田修平; 青木拓也, 日本内科学会雑誌, 114, 2025年

• 妊婦における社会経済要因・喫煙と妊娠前の低体重・肥満との関連(エコチル調査)
  西條 泰明; 吉岡 英治; 佐藤 遊洋; 九里 優輝; 金谷 智子; 中西 研太郎; 加藤 育民; 長屋 健; 高橋 悟; 伊藤 善也; 岩田 啓芳; 山口 健史; 宮下 ちひろ; 伊藤 佐智子; 岸 玲子
  日本衛生学雑誌, 2025年03月, (一社)日本衛生学会, 日本語
  2025年03月 - 2025年03月

• 大学院共通授業科目（教育プログラム）：社会と健康, 2024年, 修士課程, 大学院共通科目
• 大学院共通授業科目（教育プログラム）：社会と健康, 2024年, 修士課程, 大学院共通科目
• 一般臨床医学, 2024年, 学士課程, 医学部

• PLOS One, Editorial Board
  2025年06月
  PLOS One
• BMC Public Health, Editorial Board Member
  2025年04月
  BMC Public Health