Impacts of Perinatal Dioxin Exposure on Motor Coordination and Higher Cognitive Development in Vietnamese Preschool Children: A Five-Year Follow-Up

• Published in: PloS one Vol. 11; no. 1; p. e0147655
• Main Authors: Tran, Nghi Ngoc, Pham, Tai The, Ozawa, Kyoko, Nishijo, Muneko, Nguyen, Anh Thi Nguyet, Tran, Tuong Quy, Hoang, Luong Van, Tran, Anh Hai, Phan, Vu Huy Anh, Nakai, Akio, Nishino, Yoshikazu, Nishijo, Hisao
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 29.01.2016; Public Library of Science (PLoS)
• Subjects: Autism; Autistic Disorder - chemically induced; Autistic Disorder - diagnosis; Autistic Disorder - physiopathology; Biology and Life Sciences; Breast milk; Child, Preschool; Children; Cognition - drug effects; Cognitive ability; Coordination; Dioxin; Dioxins; Dioxins - toxicity; Environmental Pollutants - toxicity; Epidemiology; Exposure; Female; Fetus; Follow-Up Studies; Food contamination; Furans; Girls; Health risk assessment; Herbicides; Humans; Infant; Infant, Newborn; Intelligence Tests; Male; Manual dexterity; Maternal Exposure; Medicine and Health Sciences; Milk; Milk, Human - chemistry; Motor Activity - drug effects; Motor Skills Disorders - chemically induced; Motor Skills Disorders - diagnosis; Motor Skills Disorders - physiopathology; Neurodevelopmental disorders; Neuropsychological Tests; People and Places; Perinatal exposure; Pesticides; Physiological aspects; Polychlorinated dibenzodioxins; Polychlorinated Dibenzodioxins - toxicity; Pregnancy; Preschool children; Research and Analysis Methods; Risk factors; Sex Factors; Social Sciences; TCDD; Toxicity; Vietnam; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0147655

Dioxin concentrations remain elevated in the environment and in humans residing near former US Air Force bases in South Vietnam. Our previous epidemiological studies showed adverse effects of dioxin exposure on neurodevelopment for the first 3 years of life. Subsequently, we extended the follow-up period and investigated the influence of perinatal dioxin exposure on neurodevelopment, including motor coordination and higher cognitive ability, in preschool children. Presently, we investigated 176 children in a hot spot of dioxin contamination who were followed up from birth until 5 years old. Perinatal dioxin exposure levels were estimated by measuring dioxin levels in maternal breast milk. Dioxin toxicity was evaluated using two indices; toxic equivalent (TEQ)-polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs) and concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Coordinated movements, including manual dexterity, aiming and catching, and balance, were assessed using the Movement Assessment Battery for Children, Second Edition (Movement ABC-2). Cognitive ability was assessed using the nonverbal index (NVI) of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). In boys, total test and balance scores of Movement ABC-2 were significantly lower in the high TEQ- PCDDs/Fs group compared with the moderate and low exposure groups. NVI scores and the pattern reasoning subscale of the KABC-II indicating planning ability were also significantly lower in the high TCDD exposure group compared with the low exposure group of boys. However, in girls, no significant differences in Movement ABC-2 and KABC-II scores were found among the different TEQ-PCDDs/Fs and TCDD exposure groups. Furthermore, in high risk cases, five boys and one girl highly exposed to TEQ-PCDDs/Fs and TCDD had double the risk for difficulties in both neurodevelopmental skills. These results suggest differential impacts of TEQ-PCDDs/Fs and TCDD exposure on motor coordination and higher cognitive ability, respectively. Moreover, high TEQ-PCDDs/Fs exposure combined with high TCDD exposure may increase autistic traits combined with developmental coordination disorder.