Factors of non-responsive or lost-to-follow-up Japanese mothers during the first year post partum following the Japan Environment and Children’s Study: a longitudinal cohort study
Zentaro Yamagata,
Hiroyasu Iso,
Takeo Nakayama,
Reiko Kishi,
Nobuo Yaegashi,
Koichi Kusuhara,
Mika Kigawa,
Akiko Tsuchida,
Mika Ito,
Tomomi Tanaka,
Kei Hamazaki,
Yuichi Adachi,
Shigeru Saito,
Hideki Origasa,
Hidekuni Inadera,
Michihiro Kamijima,
Kenta Matsumura,
Ayako Takamori,
Toshihiro Kawamoto,
Yukihiro Ohya,
Koichi Hashimoto,
Chisato Mori,
Shuich Ito,
Masayuki Shima,
Yasuaki Hirooka,
Narufumi Suganuma,
Takahiko Katoh
Affiliations
Zentaro Yamagata
Centre for Birth Cohort Studies, University of Yamanashi - Graduate School of Medical Science Campus, Chuo, Japan
Hiroyasu Iso
3 Osaka Regional Center for Japan Environment and Children’s Study (JECS), Osaka University, Suita, Osaka, Japan
Takeo Nakayama
Department of Health Informatics, Kyoto University School of Public Health, Kyoto, Japan
Reiko Kishi
Center for Environmental and Health Sciences, Hokkaido University, Sapporo, Japan
Nobuo Yaegashi
Koichi Kusuhara
1 Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan
Mika Kigawa
1 Department of Liberal Arts and Human Development, Kanagawa University of Human Services, Yokosuka, Japan
Akiko Tsuchida
Department of Public Health, University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, Toyama, Japan
Mika Ito
5 Department of Obstetrics and Gynecology, Faculty of Medicine, University of Toyama, Graduate School of Medicine and Pharmaceutical Science for Education, Toyama, Japan
Tomomi Tanaka
Department of Pediatrics, University of Toyama Faculty of Medicine Graduate School of Medicine and Pharmaceutical Science for Education, Toyama, Japan
Kei Hamazaki
Department of Public Health, University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, Toyama, Japan
Yuichi Adachi
Toyama Regional Center for JECS, University of Toyama, Toyama, Japan
Shigeru Saito
Department of Cardiology, Shonan Kamakura General Hospital, Kamakura, Japan
Hideki Origasa
7 Division of Biostatistics and Clinical Epidemiology, Faculty of Medicine, University of Toyama, Graduate School of Medicine and Pharmaceutical Sciences, Toyama, Japan
Hidekuni Inadera
3 Toyama Regional Centre for Japan Environment and Children’s Study, University of Toyama, Toyama, Japan
Michihiro Kamijima
Department of Occupational and Environmental Health, Nagoya City University Graduate School of Medical Sciences and Medical School, Nagoya, Aichi, Japan
Kenta Matsumura
Department of Public Health, University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, Toyama, Japan
Ayako Takamori
Clinical Research Center, Saga University Hospital, Saga, Japan
Toshihiro Kawamoto
Yukihiro Ohya
Koichi Hashimoto
Fukushima Regional Center for the Japan Environment and Children’s Study, Fukushima, Japan
Objectives We examined the factors related to lost-to-follow-up of a birth cohort study during the first year after delivery.Design Longitudinal cohort study.Setting Questionnaires were provided by mail. Mothers answered the questionnaires about the children twice: at 6 months and 1 year.Participants Of 103 062 pregnancies who consented to participate in the Japan Environment and Children’s Study (JECS), 93 417 mothers were included in the study after excluding those with multiple births, miscarriages or stillbirths and those who withdrew from the study within 1 year after providing informed consent.Primary and secondary outcome measures Participants’ socioeconomic status, medical history, health status, health-related behaviours, their children’s health conditions and living situations were collected by self-administered questionnaires during pregnancy or 1 month after delivery as the baseline survey. In addition, two self-administered questionnaires were distributed 6 months and 1 year after delivery. Using the response status of the two questionnaires after delivery, participants’ follow-up status was divided into four groups. The related factors were examined using logistic regression analysis.Results Factors positively correlated with lost-to-follow-up to the questionnaires were postpartum physical conditions, psychological distress during pregnancy, the child’s health status at birth, the child’s primary caregiver and the number of siblings of the child. Partners’ active participation in JECS was associated with a lower lost-to-follow-up rate to the two questionnaires, whereas inactive participation was positively associated with a higher lost-to-follow-up rate.Conclusion The response rate to the questionnaires seems to be related to the interest and understanding of participants’ partners. In addition, the response rates are related to participants’ physical conditions and living conditions. To decrease lost-to-follow-up rates in consecutive questionnaire surveys within a cohort study, it may be important for investigators to recognise that participants and their motivation in research can be influenced by perceptions they may have regarding the objectives of the research.
