Androgen disruption by dioxin exposure in 5-year-old Vietnamese chil- dren: Decrease in serum testosterone level Nguyen Thi Phuong Oanh a , Teruhiko Kido b, ⁎, Seijiro Honma b , Yuko Oyama a , Le Thai Anh a , Hoang Duc Phuc c , Nguyen Hoang Viet d , Ho Dung Manh e , Rie Okamoto b , Hideaki Nakagawa f , Shoji F. Nakayama g , Dang Duc Nhu h , Dao Van Tung i , Vo Van Chi j , Nguyen Hung Minh k , Ngo Van Toan l a Division of Health Science, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Japan b Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Japan c Hanoi Preventive Medicine Centre, No. 70 Nguyen Chi Thanh, Dong Da, Hanoi, Viet Nam d Faculty of Medical Technology, Ha Noi Medical University, No. 1 Ton That Tung, Dong Da, Hanoi, Viet Nam e Faculty of Pharmacy, Lac Hong University, No. 10 Huynh Van Nghe, Buu Long, Bien Hoa, Dong Nai, Viet Nam f Department of Epidemiology and Public Health, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Japan g Centre for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Japan h Ministry of Health, No 138A Giang Vo, Ba Dinh, Hanoi, Viet Nam i Viettiep Hospital, No.1 Nha Thuong, Le Chan, Hai Phong, Viet Nam j Phu Cat Health Centre, No.12, 2/3 St., Ngo May, Phu Cat, Binh Dinh, Viet Nam k Dioxin Laboratory, Centre for Environment Monitoring, Vietnam Environment Administration, No. 556 Nguyen Van Cu, Long Bien, Hanoi, Viet Nam l Ha Noi Medical University, No. 1 Ton That Tung, Dong Da, Hanoi, Viet Nam HIGHLIGHTS • The cohort study has been conducted in one of three dioxin hotspot areas in Vietnam. • Seven serum steroid hormones were analysed from 5-year-old children in the hotspot. • DHEA and T levels were significantly lower in the hotspot. • The A-dione level was significantly higher in the hotspot. • DHEA, A-dione, and T significantly cor- related with dioxin levels in breast milk. GRAPHICAL ABSTRACT abstract article info Article history: Received 15 February 2018 Received in revised form 27 April 2018 Accepted 21 May 2018 Available online xxxx Editor: Adrian Covaci Dioxins have been suspected to be potential substances causing endocrine disruptions in humans. We are conducting the research in one of three dioxin exposure areas (hotspots) in Vietnam. We previously reported that the salivary dehydroepiandrosterone (DHEA) level decreased in 3-year-old Vietnamese children and that it was significantly inversely correlated with polychlorinated dibenzodioxin/dibenzofuran levels in their mother's breast milk. In this study, we investigated the influence of exposure to dioxin on steroid hormone bio- synthesis in the same children when they reached 5 years of age, focusing on androgens. Thirty-five and 50 mother–child pairs from dioxin hotspot and non-sprayed areas, respectively, participated in this study. Maternal Science of the Total Environment 640–641 (2018) 466–474 ⁎ Corresponding author at: Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920- 0942, Japan. E-mail address: kido@mhs.mp.kanazawa-u.ac.jp (T. Kido). https://doi.org/10.1016/j.scitotenv.2018.05.257 0048-9697/© 2018 Published by Elsevier B.V. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv