53 The association between maternal preconception BMI and child zBMI growth rates

Abstract

Abstract Background Elevated body mass index (BMI) and rapid growth in early childhood are important predictors of obesity risk. While studies have identified an association between maternal preconception BMI and child BMI z-scores (zBMI), the association with zBMI growth rates during distinct growth periods is unclear. Objectives To assess the association between maternal preconception BMI and child zBMI growth rates and BMI z-scores, in children aged 0 to 10 years old. Additionally, to examine whether child sex and gestational weight gain (GWG) modify these associations. Design/Methods This longitudinal study consisted of healthy children (0 to 10 years) enrolled in a primary care practice-based research cohort. The exposure was maternal BMI measured during the preconception period, defined as the 2 years prior to pregnancy. The primary outcome was child zBMI growth, modeled with piecewise linear splines for age. The secondary outcome was repeated measures of child BMI z-scores. Piecewise linear mixed models were used to determine the association with growth, while linear mixed models were used for zBMI. Effect modification by child sex and GWG was explored. Results 499 children were included. Maternal preconception BMI had a small, but statistically significant association with child zBMI growth rates during some growth periods, with the strongest association from 0 to 4 months (0.007; p=0.004). Maternal preconception BMI was also associated with child zBMI; 1kg/m2 increase was associated with 0.03 zBMI increase (p=0.001). Child sex and maternal GWG did not modify these associations. Conclusion There is evidence to suggest an association between maternal preconception BMI and child zBMI growth and scores. In addition to maternal and pregnancy benefits, preconception interventions may have longer-term benefits for child growth.