Abstract
OBJECTIVES: The long-term effects of infant weight gain and motor development on adiposity and physical activity remain unclear. This study investigates how these factors predict objectively assessed adiposity and physical activity at early school age, and whether these associations persist into preadolescence. METHODS: This retrospective study with prospective follow-up included 223 first-grade children (aged 6-7) for initial assessments, including body fat percentage determined by dual-energy X-ray absorptiometry and moderate-to-vigorous physical activity (MVPA) assessed using an accelerometer. A four-year follow-up involved 216 fifth-grade children (aged 10-11). Data on weights measured at birth and at 1-, 3-4-, and 18-month checkups, along with ages at which six gross motor milestones were achieved, were extracted from the Maternal and Child Health Handbook. RESULTS: Multivariable regression analyses, adjusted for sex, gestational age, height, school location, maternal age, and pre-pregnancy body mass index showed that rapid weight gain from birth to 18 months (p = 0.01) and later age at standing with support (p < 0.001) were independently associated with higher body fat assessed in the first grade, with a significant negative interaction (p = 0.02). Later age at standing with support was also significantly associated with less MVPA time in the first grade (p = 0.02). Among these, only the association between age at standing with support and body fat remained significant in the fifth grade (p < 0.01). CONCLUSIONS: This study highlights the long-term implications of later achievement of motor milestones for future adiposity, persisting into preadolescence. Infant motor development can be an important determinant of future health.