Adverse effects of dioxins on cognitive ability and motor performance of 5-year-old children residing in a hotspot of dioxin contamination originating from Agent Orange in Vietnam: A prospective cohort study

• Published in: The Science of the total environment 2022-08, Vol.833, p.155138-155138, Article 155138
• Main Authors: Trang, Thieu Ban, Tai, Pham The, Nishijo, Muneko, Anh, Tran Ngoc, Thao, Pham Ngoc, Hoa, Vu Thi, Nghi, Tran Ngoc, Van Luong, Hoang, Nishijo, Hisao
• Format: Article
• Language: English
• Subjects: Agent Orange; Child; Cognitive ability; Dioxin; Motor coordination
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.155138

Bien Hoa airbase is the most dioxin-polluted hotspot in Vietnam. In 2012, a birth cohort living around Bien Hoa airbase was recruited for assessment of physical and neurological development. In the present study, neurodevelopment scores at 5 years of age were assessed by the Kaufman Assessment Battery for Children, Second Edition and the Movement Assessment Battery for Children, Second Edition for 185 children in Bien Hoa and 104 children in Ha Dong (unexposed control group) to clarify the effects of dioxin. 2,3,7,8-tetrachlorodibenzo-p-dioxin concentrations in breast milk of women in Bien Hoa were approximately three times higher than those of women in Ha Dong (2.33 vs. 0.69 pg/g fat, p < 0.001). In general, neurodevelopment scores were lower in Bien Hoa children than in Ha Dong children. In boys, scores differed for number recall (12.6 vs. 14.0, p = 0.036), triangles (10.7 vs. 12.4, p = 0.005), manual dexterity (8.3 vs. 9.7, p = 0.037), balance (7.4 vs. 10.3, p < 0.001), and total movement scores (8.0 vs. 10.1, p = 0.003). After adjusting for covariates, linear regression analysis indicated that the scores of the triangles, balance, and total movement tests were inversely associated with levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin and of toxic equivalency of polychlorinated dibenzodioxins and polychlorinated dibenzofurans. In girls, scores differed for the triangles test (11.0 vs. 12.6, p = 0.005), hand movement test (9.6 vs. 11.3, p = 0.003), and balance test (9.1 vs. 10.7, p = 0.050); toxic equivalency of polychlorinated dibenzofurans was inversely associated with hand movement and balance scores. Overall, perinatal dioxin exposure appears to have a long-term impact on neurodevelopment. [Display omitted] •Dioxin levels in breast milk were three times higher in the sprayed area.•Child cognitive and motor scores were significantly lower in the sprayed area.•Cognitive and motor scores were inversely associated with dioxin exposure.•Perinatal dioxin exposure has a long-term impact on child neurodevelopment.