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Your Environment. Your Health.

Hokkaido Birth Cohort Study on Environment and Children’s Health (Large-scale Hokkaido Cohort)

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Centre Hokkaido University
Reiko Kishi, M.D., Ph.D.
Professor and Deputy Director
Hokkaido University Center for Environmental and Health Sciences
Description of cohort This large-scale Hokkaido cohort (n=20,940) recruited Japanese women at 13 weeks of pregnancy from 37 hospitals. Children of the mothers were followed until puberty. This is part of an ongoing cohort study to examine the potential negative effects of perinatal environmental chemical exposures on birth outcomes, neurodevelopment, and allergy, and to identify individuals genetically susceptible to environmental chemicals.
Website Link
Location of cohort Hokkaido, Japan
Chemicals/Exposures studied Chlorinated compounds (PCB, dioxins, PCDD, PCDF ), perfluorinated compounds (PFOS, PFOA and other PFAAs), phthalate metabolites, chlorinated pesticides, BPA, cotinine, folic acid
Health or social effects studied Congenital malformations, reduced birth size, growth, neurodevelopment, IQ, allergy, infectious diseases, imbalance of thyroid hormones and reproductive hormones
Samples collected Maternal and cord blood, child urine
Questionnaires Yes; baseline questionnaire during pregnancy, medical birth record, children's follow-up questionnaires
Key Findings

The prevalence of folate deficiency (<6.8 nmol/L) among Japanese pregnant women was 0.3%. Maternal 5,10-MTHFR C677T polymorphism, but not the 5,10-MTHFR A1298C variant, is independently associated with improvement in infant birth weight, especially among nonsmokers.

In addition, our group reported exposure levels of 11 types of PFAAs among pregnant women between 2003 and 2011. Whereas PFOS and PFOA concentrations declined, PFNA and PFDA levels increased. Also, higher maternal perfluorotridecanoic acid (PFTrDA) levels showed immunosuppressive effects on eczema and allergic diseases among female infants at 24 months of age.

Kishi R, Sasaki S, Yoshioka E, Yuasa M, Sata F, Saijo Y, Kurahashi N, Tamaki J, Endo T, Sengoku K, Nonomura K, Minakami H: Cohort Profile: The Hokkaido Study on Environment and Children’s Health in Japan. Int J Epidemiol 2011, 40:611-618. [Abstract]

Kishi R, Kobayashi S, Ikeno T, Araki A, Miyashita C, Itoh S, Sasaki S, Okada E, Kobayashi S, Kashino I, Itoh K, Nakajima S, The members of the Hokkaido Study on Environment Children’s H: Ten years of progress in the Hokkaido birth cohort study on environment and children’s health: cohort profile-updated 2013. Environ Health Prev Med 2013, 18:429-450. [Abstract]
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