Association of dioxin exposure and reproductive hormone levels in men living near the Bien Hoa airbase, Vietnam Hoang Van Luong a , Pham The Tai a, ⁎, Muneko Nishijo b , Do Minh Trung a , Pham Ngoc Thao a,b , Pham Van Son a , Nguyen Van Long a , Nguyen Tung Linh a , Hisao Nishijo c a Biomedical and Pharmaceutical Research Center, Vietnam Military Medical University, 160-Phung Hung, Ha Dong, Ha Noi, Viet Nam b Department of Epidemiology and Public Health, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa 920-0293, Japan c System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan HIGHLIGHTS • We studied the effects of dioxin on re- productive hormone levels in Vietnamese men. • Dioxin and total testosterone levels were negatively correlated. • Dioxin and prolactin levels were posi- tively correlated. • Future studies should assess dioxins' ef- fects on the endocrine system as a whole. GRAPHICAL ABSTRACT abstract article info Article history: Received 18 December 2017 Received in revised form 8 February 2018 Accepted 8 February 2018 Available online xxxx Editor: Adrian Covaci Dioxins are endocrine-disrupting chemicals, and their effects on reproductive functions are well-documented. The aim of the present study was to measure the levels of reproductive hormones in 42 men residing near a dioxin-contaminated area in Vietnam. We measured levels of 17 2,3,7,8-substituted congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) and four non-ortho polychlorinated biphenyls (PCBs) in blood. Levels of follicle-stimulating hormone, luteinizing hormone, proges- terone, prolactin, estradiol, and total testosterone were measured in serum. Blood dioxin levels were elevated; the levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin was 7.3 pg/g fat. Seven of the men had testosterone levels below 250 ng/dL, and nine men had prolactin levels above 9.7 ng/mL. Four PCDD congeners, two PCDF congeners, one PCB congener, and the sum TEQ of PCDDs, PCDDs/Fs, and PCDDs/Fs/PCBs were positively and significantly correlated with prolactin levels. Two PCDD congeners, six PCDF congeners, two PCB congeners, and the TEQs of PCDFs and PCBs were negatively and significantly correlated with testosterone levels. There were no signifi- cant correlations between dioxin congeners and follicle-stimulating hormone, luteinizing hormone, or progester- one levels. © 2018 Elsevier B.V. All rights reserved. Keywords: Agent Orange Prolactin Testosterone Endocrine system Science of the Total Environment 628–629 (2018) 484–489 Abbreviations: 2,3,7,8-TetraCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin; PCDDs, polychlorinated dibenzo-p-dioxins; PCDFs, polychlorinated dibenzofurans; PCBs, polychlorinated biphe- nyls; TEQ, toxic equivalent; GM, geometric mean; GSD, geometric standard deviation; SD, standard deviation; FSH, follicle-stimulating hormone; LH, luteinizing hormone. ⁎ Corresponding author at: Pham The Tai, Biomedical and Pharmaceutical Research Center, Vietnam Military Medical University, 160-Phung Hung, Ha Dong, Ha Noi, Viet Nam. E-mail address: phamthetai@vmmu.edu.vn (P.T. Tai). https://doi.org/10.1016/j.scitotenv.2018.02.094 0048-9697/© 2018 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv