Diet quality in childhood is prospectively associated with the timing of puberty but not with body composition at puberty onset.

We examined whether the diet quality of healthy children prior to the pubertal growth spurt was associated with age and body composition at puberty onset. Multivariate regression analyses were performed using data from 222 Dortmund Nutritional and Anthropometric Longitudinally Designed Study participants (mean age +/- SD at baseline: 7.4 +/- 1.3 y) with 3-d weighed dietary records and anthropometric data at baseline, i.e. the visits 2 and 3 y before the onset of pubertal growth spurt [defined as age at take-off (ATO)]. Diet quality at baseline was determined using the nutrient density-based Nutritional Quality Index (NQI) and the food group and nutrient-based Revised Children's Diet Quality Index (RC-DQI). Based on their distribution, 3 NQI or RC-DQI categories were created to indicate lower, moderate, and higher diet quality. Parameters describing body composition at ATO were age- and gender-specific Z-scores of BMI, fat mass/height(2), and fat-free mass/height(2). Children with lower diet quality indicated by lower NQI scores entered puberty approximately 0.4 y earlier than children with higher NQI scores {ATO in lower and higher NQI categories were [mean (95% CI)] 9.2 y (9.0-9.4), and 9.6 y (9.4-9.9), adjusted for sex, maternal overweight, baseline energy intake, and baseline BMI Z-score} (P-value = 0.02). A similar association of the RC-DQI with ATO was largely explained by baseline energy intakes. Our data suggest that diet quality was not independently associated with body composition at ATO. Children with lower diet quality according to a nutrient density-based index appear to enter puberty at an earlier age, independently of prepubertal body composition.