Relationships between maternal body mass index and child cognitive outcomes at 3 years of age are buffered by specific early environments in a prospective Canadian birth cohort
- DOI
- Language of the publication
- English
- Date
- 2022-04-28
- Type
- Article
- Author(s)
- West, Zoe
- Demchenko, Iryna
- Clark, Lee
- White, Marina
- MacFarlane, Amanda J.
- Fraser, William D.
- Arbuckle, Tye E.
- Connor, Kristin L.
- Publisher
- Cambridge University Press
Abstract
Fetal and child development are shaped by early life exposures, including maternal health states, nutrition and educational and home environments. We aimed to determine if suboptimal pre-pregnancy maternal body mass index (BMI; underweight, overweight, obese) would associate with poorer cognitive outcomes in children, and whether early life nutritional, educational and home environments modify these relationships. Self-reported data were obtained from mother-infant dyads from the pan-Canadian prospective Maternal-Infant Research on Environmental Chemicals cohort. Relationships between potential risk factors (pre-pregnancy maternal BMI, breastfeeding practices and Home Observation Measurement of the Environment [HOME] score) and child cognitive development at age three (Weschler’s Preschool and Primary Scale of Intelligence, Third Edition scale and its subcategories) were each evaluated using analysis of variance, multivariable regression models and moderating analyses. Amongst the 528 mother−child dyads, increasing maternal pre-pregnancy BMI was negatively associated with scores for child full-scale IQ (β [95% CI]; −2.01 [−3.43, −0.59], p = 0.006), verbal composite (−1.93 [−3.33, −0.53], p = 0.007), and information scale (−0.41 [−0.70, −0.14], p = 0.003) scores. Higher maternal education level or HOME score attenuated the negative association between maternal pre-pregnancy BMI and child cognitive outcome by 30%–41% and 7%–22%, respectively, and accounted for approximately 5%–10% greater variation in male children’s cognitive scores compared to females. Maternal education and higher quality home environment buffer the negative effect of elevated maternal pre-pregnancy BMI on child cognitive outcomes. Findings suggest that relationships between maternal, social and environmental factors must be considered to reveal pathways that shape risk for, and resiliency against, suboptimal cognitive outcomes in early life.
Plain language summary
Health Canada is responsible for helping Canadians maintain and improve their health. The aim of this study was to examine whether maternal body mass index (BMI) prior to pregnancy was associated with lower IQ scores in young children. Furthermore, the study looked to see if maternal education and home environment modified these associations. In this MIREC biobank project, researchers at Carleton University examined associations between child IQ at age 3 years and pre-pregnancy BMI, maternal education level, breastfeeding practices and the HOME score. The HOME score is a measure of the quality of a child's home environment such as emotional support provided by the family and activities providing general stimulation for thinking, concentration and memory. Amongst the 528 mother-child pairs examined, the researchers found that women with higher pre-pregnancy BMI tended to have children with about 2 points lower IQ scores, although this association was not statistically significant. The study also found that when the HOME score was higher and mothers had higher education, the negative association between maternal BMI and child’s IQ score was reduced. In summary, higher pre-pregnancy BMI was associated with slightly lower IQ scores in their child. However, higher maternal education and a better home environment were found to lessen this association. These findings suggest that relationships between maternal, social, and environmental factors are important factors associated with child IQ.
Subject
- Health,
- Health and safety