1. Perinatal dioxin exposure and infants’ neurodevelopment-A follow up study in Da Nang, Vietnam Pham The Tai, M.D., Ph.D. Biomedical and pharmaceutical research center-Vietnam Military Medical University

2. The development during the fetal and infant periods is highly sensitive to environmental toxicants In a Dutch study, a significantly negative association between prenatal dioxin exposure and psychomotor development at 7 months of age was reported (Koopman-Esseboom et al. 1996) In Japanese study, some chlorinated dibenzo-p-dioxins (PCDD)/dibenzofurans (PCDF) congeners exhibited significantly negative associations with both the psychomotor and mental development of 6- month-old infants (Nakajima et al. 2006). Dioxins and infant development Worldwide studies

3. An epidemiological study about effects of dioxin on infant health in Vietnam

4. Dioxin contamination in Vietnam From 1961 to 1971, over 71 million liters of herbicides were sprayed over approximately 10  of South Vietnam, below the former demilitarized zone at the 17 th parallel. Agent Orange was the most abundantly sprayed, approximately two-thirds of the total sprayed herbicides. Agent Orange was contaminated with the most toxic dioxin congener 2,3,7,8- tetrachlorodibenzo- p -dioxin (2,3,7,8- TetraCDD). Former US airbases (Bien Hoa, Phu Cat and Da Nang), which were used to store and transfer herbicides became “hot spot” of dioxin contamination.

5. 17 th parallelLocations Son Tra Thanh Khe Airbase Thanh Khe district in Da Nang city locating within 3km from Da Nang airbase – a hot spot of dioxin Son Tra district was about 7km from Da Nang airbase and separated by a river

6. Recruitment of Subjects 4 months 12 months 3 years 1 month At birth In 2008 and 2009: 158 in Thanh Khe and 80 mother- infant pairs in Son Tra were recruited. Birth sizes of infants: Weight, Length, Head and Abdominal circumference were measured

7. Cause and effects Body growth Neurodevelopment Confounding factors Dioxin in breast milk Daily Dioxin Intake (DDI)

8. Equipment: Estimate Cause 10 g breast milk was used to extract fat content. A series of purification operations consisting of alkali digestion, hexan extraction and chromatography were performed. The final extract were concentrated to 20 µl and analyzed by gas chromatography coupled with high-resolution mass spectrometry (HRMS, HR-GC/MS, MA Station-JMS, JEOL, Japan) Seventeen 2,3,7,8-substitued congeners of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) was quantified and fat-base calculated DDI = (volume of milk per day in ml) × (  fat content of milk/100) × (PCDDs/PCDFs TEQ in breast milk in pg/g lipid)/ (infant weight in kg).

9. Neurodevelopment Bayley-III Cognitive Language Motor Body sizes Weight Length Head and abdominal circumference Equipment : Estimate Effects

10. Survey at 1 month of age 4 months 12 months 3 years At birth 1 month 20 ml of breast milk from each mother was collected Measure baby sizes: Weight, Length, Head and Abdominal circumference

11. Survey at 4 months of age 4 months 12 months 3 years At birth 1 month Assess Neurodevelopment by Bayley test Measure body sizes: Weight, Length, Head and Abdominal circumference Questionnaire : Basic information of mother-infant

12. Survey at 12 months of age 4 months 12 months 3 years At birth 1 month Assess Neurodevelopment by Bayley test Social emotional and Adaptive Behavior Questionnaire. Measure body sizes: Weight, Length, Head and Abdominal circumference Questionnaire : Mothers’ daily meal

13. Survey at 3 years of age 4 months 12 months 3 years At birth 1 month Assess Neurodevelopment by Bayley test Social emotional and Adaptive Behavior Questionnaire. Measure body sizes: Weight, Length, Head and Abdominal circumference ASRS Questionnaire for Autism Rating Food Questionnaire for Infants Urine Collection Basic information of Parents

14. Results  Dioxin concentrations in breast milk of mothers and DDI of infants living around Da Nang airbase.  Perinatal dioxin exposure and body growth of infants  Perinatal dioxin exposure and neurodevelopment of infants

15. Figure 1. Daily dioxin intake of nursing infants United State : Daily dioxin intake in during the first year of life ( Source: Intake of dioxins and related compounds from food in US population. Schecter. A et al. J toxicol Environ Health A.2001 May 11; 63 (1):1-18) Japan: Daily dioxin intake in nursing infants ( Source: Report on Tolerable Daily Intake (TDI) of Dioxins and Related Compounds. Environment Agency &Ministry of Health and Welfare 1999) DDI = (volume of milk per day in ml) × (  fat content of milk/100) × (PCDDs/PCDFs TEQ in breast milk in pg/g lipid)/ (infant weight in kg).

17. Gender Differences in Dioxin Effects on Infant Growth Maternal dioxin exposure affected infant weight and BMI in boys at 4 months after birth, because significantly low measurements were observed in boys exposed to higher levels of dioxins

18. Impact of perinatal dioxin exposure on infant growth: A cross- sectional and longitudinal studies in dioxin-contaminated areas in Vietnam Muneko Nishijo1, Pham The Tai1,2, Hideaki Nakagawa1, Shoko Maruzeni1, Nguyen Thi Nguyet Anh1, Hoang Van Luong2, Tran Hai Anh2, Ryumon Honda3, Yuko Morikawa3,Teruhiko Kido4, Hisao Nishijo5 Abstract Dioxin exposure levels remain elevated in residents living around former US Air Force bases in Vietnam, indicating potential adverse impacts on infant growth. In this study, 210 mother–infant pairs in dioxin-contaminated areas in Vietnam were recruited at the infants’ birth and followed up for 4 months. Perinatal dioxin exposure levels were estimated by measurement of polychlorinated dibenzo-p-dioxins/furans toxic equivalent (PCDDs/Fs-TEQ) in breast milk. The infants’ size was measured at birth and 1 and 4 months after birth, and neurodevelopment was evaluated using the Bayley Scales III at 4 months of age. Among 4 dioxin groups (<25, 25–50, 50-75,  75 percentile of PCDDs/Fs-TEQ), cross-sectional comparisons of body size and neurodevelopment scales and comparisons of longitudinally assessed body size were performed respectively. At birth, head circumference of girls in the ≥75 percentile group was significantly larger than those in the <25 and 50–75 percentile groups. At 4 months of age, the weight and body mass index (BMI) of boys in the ≥75 percentile group were significantly lower than those in the other groups. Increase in weight was significantly lower in the ≥75 percentile group in both sexes from birth to 1 month but only in boys at 1–4 months of age. Estimated marginal mean values in a mixed model of weight and BMI during the first 4 months of life were significantly lower in the ≥75 percentile group in boys. In girls, marginal mean values for head circumference were increased with increase in dioxin levels. Only in boys, cognitive, language, and fine motor scores in the ≥75 percentile group were significantly lower than those in the other groups. These results suggested a considerable impact of perinatal dioxin exposure on infant growth, particularly in boys exposed to PCDDs/Fs-TEQ levels higher than the threshold value. Key words: dioxins; breast milk; infant growth; neurodevelopment; Vietnam

19. Figure 2. Dioxin exposure and neurodevelopmental scores

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22. Ha Noi, 2013