Effects of Environmental Exposure to Polychlorinated Biphenyls and Dioxins on Birth Size and Growth in Dutch Children

Abstract

Lower birth weight and growth retardation has been found in studies with laboratory animals, in children born of mothers exposed to accidental high levels of polychlorinated biphenyls (PCBs) and related compounds, and in children born of mothers who consumed PCB-contaminated fish. The effect of background exposure to PCBs and dioxins on birth size and growth in human newborns, however, is still unknown. This study examined birth size and postnatal growth of term newborns in relation to their background PCB and dioxin exposure. Birth weight and weight, length, and head circumference were measured at 10 d and 3, 7, 18, and 42 mo of age in 207 children, of whom 105 were breast-fed and 102 were formula-fed during infancy. The effect of in utero exposure to PCBs on birth size, assessed by cord and maternal plasma PCB levels, was investigated in the whole group. The effect of prenatal PCB exposure on postnatal growth was studied in the formula-fed group, whereas the effect of prenatal as well as lactational exposure to PCBs and dioxins on postnatal growth was studied in the breast-fed group. After adjustment for covariates, cord and maternal plasma PCB levels where both negatively associated with birth weight. Infants with high cord plasma PCB levels (P90 = 0.80 microL) weighed 165 g less compared with infants with low cord plasma PCB levels (P10 = 0.20 microg/L). Cord and maternal plasma PCB levels where both significantly associated with lower growth rate, defined as change in SD score (SDS) of weight, length, and head circumference from birth to 3 mo in the formula-fed group (all p values <0.05). No negative effects of prenatal PCB exposure on growth rate were found from 3 to 42 months of age. Postnatal PCB and dioxin exposure was not negatively associated with growth rate in the breast-fed group. In utero exposure to environmental levels of PCBs is negatively associated with birth weight and postnatal growth until 3 mo of age. Although this growth delay was described in healthy term born infants, intrauterine and postnatal growth retardation are potentially harmful to the developing human and should be avoided by reducing maternal PCB and dioxin body burden, and consequently fetal exposure to these pollutants.

Maternal contamination with PCBs and reproductive outcomes in an Australian population

“…In human studies, maternal contamination with PCBs has been reported to be associated with low birth weight (Fein et al, 1984;Patandin et al, 1998;Rylander et al, 1998), smaller head circumference (Fein et al, 1984), shorter height in males (Dewailly et al, 1993) and shorter gestational length (Fein et al, 1984;Taylor et al, 1989), although results have not been consistent. Our aim was to investigate a range of adverse reproductive outcomes in women, using breast milk PCB concentration as a measure of body burden.…”

“…Polychlorinated Biphenyls (PCBs) a group of polycyclic chlorinated hydrocarbons, are widespread environmental contaminants (Fein et al, 1984;Patandin et al, 1998), likely to possess oncogenic and teratogenic properties (Lackmann et al, 1996). PCBs consist of mixtures of 210 different isomers with various degrees of chlorination.…”

“…Their importation into Australia was prohibited in 1976 but their industrial use continued after this date (Sim, 1993) and human exposure to PCBs is still continuing mainly through the food chain (Fein et al, 1984;Patandin et al, 1998). PCBs are lipophilic and resistant to either chemical or biological degradation and accumulate in the fat tissue of animals and humans (Patandin et al, 1998).…”

“…The human fetus can be exposed to PCBs through placental transport and later during breast-feeding (Rogan et al, 1988;Lackmann et al, 1996). Prenatal exposure to PCBs has caused developmental toxic effects in the litter of experimental animals, such as reduced birth weight, abortion or neonatal mortality in monkeys, rats and sea lions (DeLong et al, 1973;Fein et al, 1984;Patandin et al, 1998).…”

2,3,7,8-Tetrachlorodibenzo-p-dioxin in maternal breast milk and newborn head circumference

“…However, the relationships between individual biological measurements of exposure and birth weight were not clarified, and head circumference was not used as an index of fetal growth in these surveys. In a Dutch population-based study with the background level of exposure, Patandin et al (1998) showed inverse association of cord/maternal plasma PCBs with birth weight and growth rate, including head circumference, from 0 to 3 months of age, but they did not investigate the relationship between maternal TCDDs/TCDFs levels and newborn size. At that time, dioxins in breast milk were quantified as the dioxin toxic equivalent (TEQ), which was then multiplied by the duration, in weeks, of breast feeding to obtain an index of postnatal exposure.…”