Association of prepubertal body composition in healthy girls and boys with the timing of early and late pubertal markers.

BACKGROUND: It is controversial whether prepubertal body composition is implicated in the timing of puberty onset.
OBJECTIVE: The objective was to investigate whether body composition in the 2 y preceding the start of the pubertal growth spurt -- a marker of puberty onset -- is associated with the attainment of early and late pubertal markers in healthy German boys and girls.
DESIGN: Multivariate-adjusted regression analyses were performed in 215 participants of the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study for whom body mass index (BMI) and its components fat mass/height(2) (FM/m(2)) and fat-free mass/height(2) (FFM/m(2)) 1 and 2 y before the onset of the pubertal growth spurt (age at takeoff; ATO) and information on early life exposures were available. In addition, age at peak height velocity (APHV) and menarche were examined.
RESULTS: Higher BMIs and FM/m(2) z scores 1 and 2 y before ATO showed modest associations with chronological age at ATO among girls only (girls: P for = trend 0.05-0.1, adjusted for early life factors; boys: P = 0.2-0.6). FFM/m(2) z scores were not related to age at ATO (P for trend = 0.5-0.8). Conversely, prepubertal BMI and FM/m(2) more clearly predicted APHV and puberty duration (APHV minus ATO) in both sexes and age at menarche in girls (girls: adjusted P for trend <0.0001-0.03; boys: P = 0.01-0.046).
CONCLUSION: This longitudinal study suggests that prepubertal body composition in healthy boys and girls may not be critical for the initiation of the pubertal growth spurt but instead affects the progression of pubertal development, which results in earlier attainment of later pubertal stages.