Domain-specific effects of prenatal exposure to PCBs, mercury, and lead on infant cognition: results from the Environmental Contaminants and Child Development Study in Nunavik.

BACKGROUND: Polychlorinated biphenyls (PCBs), methylmercury (MeHg), and lead (Pb) are environmental contaminants known for their adverse effects on cognitive development. OBJECTIVES: In this study we examined the effects of prenatal exposure to PCBs, MeHg, and Pb on cognitive development in a sample of Inuit infants from Arctic Québec. METHODS: Mothers were recruited at local prenatal clinics. PCBs, mercury (Hg), Pb, and two seafood nutrients-docosahexaenoic acid (DHA) and selenium (Se)-were measured in umbilical cord blood. Infants (n = 94) were assessed at 6.5 and 11 months of age on the Fagan Test of Infant Intelligence (FTII), A-not-B test, and Bayley Scales of Infant Development-2nd Edition (BSID-II). RESULTS: Multiple regression analyses revealed that higher prenatal PCB exposure was associated with decreased FTII novelty preference, indicating impaired visual recognition memory. Prenatal Hg was associated with poorer performance on A-not-B, which depends on working memory and is believed to be a precursor of executive function. Prenatal Pb was related to longer FTII fixation durations, indicating slower speed of information processing. CONCLUSIONS: PCBs, MeHg, and Pb each showed specific and distinct patterns of adverse associations with the outcomes measured during infancy. By contrast, none of these exposures was associated with performance on the BSID-II, a global developmental measure. The more focused, narrow band measures of cognitive function that appeared to be sensitive to these exposures also provide early indications of long-term impairment in specific domains that would otherwise not likely be evident until school age. CITATION: Boucher O, Muckle G, Jacobson JL, Carter RC, Kaplan-Estrin M, Ayotte P, Dewailly É, Jacobson SW. 2014. Domain-specific effects of prenatal exposure to PCBs, mercury, and lead on infant cognition: results from the Environmental Contaminants and Child Development Study in Nunavik. Environ Health Perspect 122:310-316; http://dx.doi.org/10.1289/ehp.1206323.

Iron-deficiency anemia in infancy and mother-infant interaction during feeding.

OBJECTIVE: This study was conducted to compare quality of mother-infant interaction during feeding in infants with or without iron-deficiency anemia (IDA). METHOD: Infants and caregivers were screened at their 9- to 10-month-old health maintenance visits at an inner-city clinic in Detroit. Those who were full-term and healthy received a venipuncture blood sample to assess iron status. Of the 77 infants who met final iron status criteria, 68 infants and mothers were videotaped during feeding interaction at the Child Development Research Laboratory. The quality of mother-infant interaction during feeding was scored on the Nursing Child Assessment Feeding Scale. Twenty-five infants with IDA (hemoglobin [HB] <110 g/L and at least 2 abnormal iron measures) were compared to 43 nonanemic infants (HB > or = 110 g/L) using analysis of variance and general linear models with covariate control. RESULTS: Mothers of IDA infants responded with significantly less sensitivity to infant cues and less cognitive and social-emotional growth fostering behavior than mothers of nonanemic infants. The pattern of results was similar for scales of contingent behaviors. The magnitude of the differences in maternal ratings was large (0.8-1.0 SD after covariate adjustment). IDA infants were rated significantly lower on clarity of cues and overall (effect sizes 0.5 SD). CONCLUSION: IDA in infancy was associated with less optimal mother-infant interaction during feeding. Future interventions might target feeding interaction and consider effects on infant iron status and developmental/behavioral outcomes among IDA infants, as well as infant feeding practices per se.

Beneficial effects of a polyunsaturated fatty acid on infant development: evidence from the inuit of arctic Quebec.

OBJECTIVES: To examine the relation of cord plasma docosahexaenoic acid (DHA) concentration to gestation length, birth size, growth, and infant visual acuity, cognitive, and motor development and the effects on growth and development associated with DHA intake from breast-feeding. STUDY DESIGN: DHA, other polyunsaturated fatty acids, and 3 environmental contaminants (polychlorinated biphenyls, mercury, and lead) were assessed in cord plasma and maternal plasma and milk in 109 Inuit infants in Arctic Quebec. Multiple regression was used to examine the relation of cord DHA and DHA from breast-feeding on growth and development at 6 and 11 months, after controlling for contaminant exposure and other potential confounders. RESULTS: Higher cord DHA concentration was associated with longer gestation, better visual acuity and novelty preference on the Fagan Test at 6 months, and better Bayley Scale mental and psychomotor performance at 11 months. By contrast, DHA from breast-feeding was not related to any indicator of cognitive or motor development in this full-term sample. CONCLUSIONS: The association of higher cord DHA concentration with more optimal visual, cognitive, and motor development is consistent with the need for substantial increases in this critically important fatty acid during the third trimester spurt of synaptogenesis in brain and photoreceptor development.

Maternal resolution of child diagnosis: stability and relations with child attachment across the toddler to preschooler transition.

In this longitudinal study, the authors investigated individual differences in how families adapt to a child's congenital disorder. Family impact, maternal grief resolution, and child attachment were assessed among 74 mothers and their toddlers with a neurological disorder or disfigurement. Fifty dyads were reevaluated 16 months later. For children with neurological compared with disfigurement diagnoses, there was a greater likelihood of negative impact on family, unresolved maternal grief, and insecure attachment at Time 1. Children classified as secure were significantly more likely to have mothers classified as resolved regarding their reactions to their children's diagnosis. Maternal grief resolution was significantly stable (77%) over time and mediated the relation between type of diagnosis and child security. With time, negative impact of child condition on the family decreased and percentage of children classified as secure increased, suggesting that on average families improved. Results suggest that helping parents come to terms emotionally and cognitively with their child's condition may be a useful focus for intervention.