Offspring sex modifies the association between early-pregnancy adiposity and 2-year-old physical activity-The Glowing...

Rodent models suggest that in utero exposure to under and overnutrition programs offspring physical activity (PA) behaviors. Such nexus has not been established in humans. This study evaluated the association of early pregnancy maternal adiposity with offspring PA at age 2 years (2-yo-PA) taking into consideration prenatal and postnatal factors.

Women (n = 153) were enrolled early in pregnancy (<10 weeks). At enrollment, maternal adiposity [air displacement plethysmography, fat mass index (FMI, kg/m²)] and PA (accelerometers, activity counts) were measured, and age, race, and education self-reported. Gestational weight gain was measured at the research facility. Offspring birthweight and sex were self-reported. At age 2 years, parental feeding practices (child feeding questionnaire) were assessed, whereas anthropometrics (length and weight) and physical activity (accelerometers) were objectively measured. Offspring body mass index z-scores were calculated. Generalized linear regression analysis modeled the association of maternal FMI and 2-yo-PA [average activity counts (AC)⁴/day].

In bivariate associations, 2-yo-PA did not associate with maternal FMI (β = -0.22, CI = -0.73 to 0.29, p = 0.398). However, maternal FMI interacted with offspring sex in association with 2-yo-PA. Specifically, 2-yo-PA was lower in girls (β = -1.14, CI = -2.1 to -0.18, p = 0.02) compared to boys when maternal FMI was ≥7 kg/m². When stratified by sex, 2-yo-PA of girls negatively associated with maternal FMI (β = -0.82, CI = -1.43 to 0.29, p = 0.009) while no association was found between maternal FMI and boy's PA (β = 0.32, CI = -0.38 to 1.01, p = 0.376).

The association of 2-yo-PA and early pregnancy maternal adiposity was modified by offspring sex. Offspring's physical activity decreased with increasing early pregnancy adiposity maternal in girls but not boys in second parity dyads.