Early Life Surgency, but not Effortful Control or Negative Affectivity, Is a Mediating Variable Between Maternal Pre-Pregnancy Body Mass Index and Childhood Obesity Risk

Maternal gestational obesity is related to risk of obesity in the child. This risk may be in part mediated by altered child temperament, which can affect mother–child interactions, including feeding and soothing behaviors that affect obesity risk. Our objective was to examine the association between maternal pre-pregnancy BMI and child zBMI and determine if child temperament, specifically positive Affectivity/Surgency, mediates this association. Using conditional process modeling, we analyzed data from 408 mother–child dyads enrolled in the Alberta Pregnancy Outcomes and Nutrition (APrON) study. Child temperament was assessed at 3 years of age via a parent report measure, the Child Behavior Questionnaire (CBQ), and child zBMI was calculated from in-person measurements of child height and weight at 4–5 years of age. Bivariate correlations showed that there was a significant positive correlation between zBMI and Surgency (r = 0.11, p = 0.03), and zBMI was also correlated with maternal pre-pregnancy BMI (r = 0.12, p = 0.02). Multivariable regression revealed that maternal pre-pregnancy BMI (adjusted β = 0.15, 95% confidence interval [CI]; 0.00–0.05, p = 0.02) and Surgency scores (adjusted β = 0.14, 95% CI; 0.02–0.28, p = 0.03) were associated with higher child zBMI at 4–5 years of age. Mediation analysis showed that Surgency mediated the association between pre-pregnancy BMI and child zBMI. Our models controlled for maternal gestational weight gain, gestational diabetes, socioeconomic status, maternal anxiety and depression, and gestational age at birth. Overall, maternal pre-pregnancy BMI was positively associated with child zBMI, and this association was mediated by higher child Surgency scores.