Dioxin exposure in breast milk and infant neurodevelopment in Vietnam

• Published in: Occupational and environmental medicine (London, England) Vol. 70; no. 9; pp. 656 - 662
• Main Authors: Tai, Pham The, Nishijo, Muneko, Anh, Nguyen Thi Nguyet, Maruzeni, Shoko, Nakagawa, Hideaki, Luong, Hoang Van, Anh, Tran Hai, Honda, Ryumon, Kido, Teruhiko, Nishijo, Hisao
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.09.2013; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adult; Air. Soil. Water. Waste. Feeding; Babies; Biological and medical sciences; Breast feeding; Breast Feeding - adverse effects; Breast milk; Breastfeeding; Breastfeeding & lactation; Chemical hazards; Cohort Studies; Congeners; Developmental Disabilities - epidemiology; Developmental Disabilities - etiology; Developmental Disabilities - physiopathology; Dioxins; Dioxins - adverse effects; Environment; Environment. Living conditions; Environmental Exposure - adverse effects; Environmental Monitoring - methods; Environmental Pollutants - adverse effects; Exposure; Female; Food contamination & poisoning; Furans; Herbicides; Humans; Incidence; Infant; Infant, Newborn; Infants; Lipids; Maternal Exposure - adverse effects; Maternal Exposure - statistics & numerical data; Maternal-Fetal Exchange - physiology; Maximum Allowable Concentration; Medical sciences; Milk, Human - chemistry; Mothers; Motor ability; PCB; Pesticides; Polychlorinated biphenyls; Pregnancy; Public health. Hygiene; Public health. Hygiene-occupational medicine; Recruitment; Risk Assessment; Vietnam; Young Adult; Asia; Vietnam; Netherlands; United States > US; Japan; Human; Chemical warfare agent; Dioxin derivatives; Health and environment; Toxicity; Infant; Nervous system; Exposure; Public health; Breast milk
• ISSN: 1351-0711; 1470-7926; 1470-7926
• DOI: 10.1136/oemed-2012-101021

Objectives Dioxin levels in the breast milk of mothers residing near hot spots of dioxin contamination areas in South Vietnam remain much higher than in unsprayed areas, suggesting that fetuses and breast-fed infants may be exposed to high levels of dioxins. The present study investigated the association of infant neurodevelopment in early infancy and dioxin exposure during the perinatal period. Methods The study involved 216 mother-infant pairs living near the Da Nang airbase, a dioxin contaminated area in Vietnam. Mothers and infants were followed from birth until infants were 4 months old. Dioxin levels in breast milk were measured to estimate the perinatal dioxin exposure, including the infant daily dioxin intake (DDI) via breastfeeding. Infant neurodevelopmental parameters, including cognitive, language and motor domains were assessed at approximately 4 months using the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III). Results The level of 2,3,7,8-tetrachlorodibenzo-p-dioxin and polychlorinated dibenzo-p-dioxins/furans-toxic equivalents in breast milk and the infant DDI showed significant inverse correlations with neurodevelopmental scores. When the subjects were divided into four groups according to dioxin levels in breast milk, the moderate and high DDI groups had significantly lower cognitive, composite motor and fine motor scores, and the high polychlorinated dibenzo-p-dioxins/furans-toxic equivalents group had significantly lower fine motor score than the low exposure group. For all domains, neurodevelopmental scores were decreased with increase in the level of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Conclusion The present study demonstrates a considerable impact of perinatal dioxin exposure on neurodevelopment in 4-month-old infants living in contaminated areas in Vietnam.