Association between infant breastfeeding practices and timing of peak height velocity: A nationwide longitudinal survey in Japan.

Abstract

Several studies have discovered an association between infant feeding practices and puberty timing; however, most have involved female cohorts. We investigated the association between infant feeding practices and the timing of peak height velocity in boys and girls. Data on infant feeding methods and anthropometric measurements were collected from a nationwide Japanese birth cohort study. The age at peak height velocity (APV, years) was estimated and compared. Subsequently, the effects of breastfeeding duration were analyzed. Of the 13,074 eligible participants, 650, 9455, and 2969 were formula-, mixed-, and exclusively breastfed, respectively. Among girls, the mean APV was significantly later in the mixed-fed (standardized regression coefficient (β): 0.094, 95% confidence interval (CI): 0.004-0.180) and exclusively breastfed (β: 0.150, 95% CI: 0.056-0.250) groups than in the formula-fed group. Among boys, the mean APV was not significantly different among the three groups; however, a sensitivity analysis that excluded preterm birth revealed more significantly delayed APV in the breastfed-only group compared to the formula-fed group. Furthermore, a multiple linear regression model revealed that a longer breastfeeding period was associated with later APV. Infant breastfeeding practices can affect the timing of peak height velocity in both boys and girls. Several studies have discovered an association between infant feeding practices and puberty timing; however, most have involved female cohorts. Age at peak height velocity, derived from longitudinal height measurements, is a useful marker of secondary sexual maturity milestones in boys and girls. A Japanese birth cohort study revealed that breastfed children had a later age at peak height velocity than their formula-fed counterparts; this was more prominent among girls than boys. Furthermore, a duration-effect relationship was observed, where longer breastfeeding duration was associated with a later age at peak height velocity.