Project Details

Pathways between maternal nutrition, toxicant exposure, home environment and child neurodevelopment

Elizabeth (Beth) Widen, PhD, RD

Summary

BACKGROUND: Maternal body mass index, pregnancy weight gain, prenatal toxicant exposures and the home environment are associated with child neurodevelopment. However, the pathways by which prenatal toxicant exposures interact with maternal body mass index and gestational weight gain to affect child neurodevelopment have not been identified, and no research findings demonstrating to what degree, if any, a nurturing home environment may mitigate these effects. GAP: We will evaluate the pathways between maternal body mass index, pregnancy weight gain, prenatal toxicant exposures, home environment and child neurodevelopment at age 3 and 7. HYPOTHESIS: We hypothesize that maternal obesity and greater pregnancy weight gain are associated with impaired child neurodevelopment at age 3 and 7. We hypothesize that effects of maternal obesity and greater pregnancy weight gain will be augmented by higher prenatal exposures to in-home pesticides and air pollution and diminished with high quality home environments. METHODS: The study is a prospective birth cohort (n=727) of American and Dominican women and their children from low-income neighborhoods in the Bronx and Northern Manhattan. The study collected information during pregnancy on maternal weight gain, environmental toxicant exposures, home environment, and socioeconomic status, and assessed child neurodevelopment at age 3 and 7 years. Sex-stratified linear regression models assessed associations between prepregnancy BMI and pregnancy weight gain z-scores with child psychomotor development index (PDI) and MDI (mental development index) scores at child age 3, and Wechsler Intelligence Scale for Children (WISC-IV) scores at approximately child age 7. RESULTS: Of 382 women with data at child age 3, 48.2% were normal weight before pregnancy, 24.1% overweight, 23.0% obese, and 4.7% underweight. At 3 years, mean scores on the PDI and MDI were higher among girls compared to boys (PDI: 102.3 vs. 97.2, P = 0.0002; MDI: 92.8 vs. 88.3, P = 0.0001). In covariate-adjusted models, maternal obesity was markedly associated with lower PDI scores in boys [β = −7.81, 95% CI: (−13.08, −2.55), P = 0.004], but not girls. Maternal BMI was not associated with MDI in girls or boys, and GWG was not associated with PDI or MDI among either sex. Of the 368 dyads with data at child age 7, prepregnancy overweight affected 23.9% of mothers and obesity affected 22.6%. At age 7, full-scale IQ was higher among girls (99.7 ± 11.6) compared to boys (96.9 ± 13.3). Among boys, but not girls, prepregnancy overweight and obesity were associated with lower full-scale IQ scores [overweight β = - 7.1, 95% CI: (- 12.1, - 2.0); obesity β = - 5.7, 95% CI: (- 10.7, - 0.7)]. GWG was not associated with full-scale IQ in either sex. After adjustment for the prenatal home environment, effects of obesity on IQ in boys were attenuated. CONCLUSIONS: We found that prepregnancy obesity was associated with lower PDI scores at 3 years, whereas maternal overweight and obesity were associated with lower IQ scores in boys, but not girls at child age 7. In contrast to our hypothesis, prenatal toxicant exposures and the postnatal home environment minimally impacted associations with child age 3 outcomes. At child age 7, prenatal toxicant exposures had no impact and a more nurturing home environment was found to lessen the negative effects of higher maternal prepregnancy BMIs at age 7 in boys. The mechanisms underlying this sex-specific association remain unclear, but due to elevated obesity exposure in urban populations, further investigation is warranted. IMPACT: This work will inform evidenced-based guidelines for women’s prepregnancy health and pregnancy weight gain that aim to optimize childhood health and neurodevelopment, and further, may aid in developing interventions and screening to identity children who need enhanced early intervention and support to enrich the home environment.

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