Prenatal exposure to polybrominated diphenyl ethers and predisposition to frustration at 7 months : results from the MIREC Study

Résumé 0

Background: Prenatal exposure to polybrominated diphenyl ethers (PBDEs) has been associated with cognitivedeficits and behavioral problems in children. To date, no study has examined this exposure in association withneurobehavioral development in infants younger than 12 months assessed with observational tasks. Objectives: This study examined the relation between prenatal PBDE concentrations and predisposition tofrustration, assessed by the arm restraint task (ART), in Canadian infants. Methods: In a prospective longitudinal study conducted in Canada, exposure to nine PBDE congeners wasmeasured in maternal plasma during the first trimester of pregnancy. The ART was used to measure predis-position to frustration in infancy (N = 333; mean age = 6.9 months), as assessed by negative vocalizations(crying and screaming) and physical reactivity (discomfort movements). Results: Maternal plasma PBDE-47 concentrations collected during pregnancy were associated with negativevocalizations using the ART (adjusted Relative Risk [aRR] = 1.04, 95% CI: 1.00, 1.09). Prenatal PBDE-99concentrations during pregnancy were also related to a shift to the left in the tail of the distribution of onset ofnegative vocalizations as measured by a decrease of 38 s (95% CI: −78.1, 1.3) in the 75th quantile of thedistribution for infants whose mothers had detectable levels of PBDE-99 compared to infants of mothers withundetectable levels. Similarly, infants whose mothers had detectable levels of PBDE-100 showed an increase of24.1 s (95% CI: 4.1, 44.1) in the 75th quantile of the distribution of proportion of time in negative vocalizationscompared with infants of mothers with undetectable levels. Finally, the association between PBDE-47 and PBDE-153, and physical reactivity was significantly modified by sex (p < 0.1), with opposite patterns in girls andboys. Conclusions: Prenatal exposure to PBDEs was associated with increased incidence of crying and screaming withdelayed onset of discomfort movement, which may indicate a predisposition to frustration and lack of habi-tuation in infants younger than 12 months from the general population.