Mercedes López-Blanco

Pubertal development in Caracas upper-middle-class boys and girls in a longitudinal context.

Changes between pubertal stages (PS) are best analyzed in a longitudinal context. A sample of 67 boys and 48 girls from the Caracas Longitudinal Study who presented data for the full range of pubertal development: genitalia (G2–G5), breast (B2–B5), pubic hair (PH2–PH5), axillary hair (AH2–AH3), and age at menarche (AM) during follow‐up, were assessed at clinical examination. Medians and standard errors for ages at each stage were estimated with the logit method. For length of intervals between stages of genitalia, breast, pubic hair and axillary hair, intervals B2–M and PH2–M, survival analysis was used according to life tables and Cox regression analysis. In boys, G2 occurred at 11.61 years; in girls, B2 occurred at 10.35 years and AM at 12.55 years of age. In both sexes, length of the intervals PS 2–3 and 3–4 were approximately 1 year, while PS 4–5 was 1.5 years. Duration of puberty reached 3.7 years in boys (G2–G5) and 3.3 years in girls (B2–B5); corresponding intervals for PH2–PH5 were 3.1 and 3.0 years in boys and girls, respectively. B2–AM was 1.8 years (with a range of 0.3–3.6 years) and PH2–AM was 1.5 years (with a range 0.3–3.5 years). These results are useful for screening and monitoring: identifying abnormal pubertal patterns in subjects who are advanced or delayed with respect to their peers, together with other pubertal events such as age at peak height and weight velocity and skeletal age. Am. J. Hum. Biol. 12:88–96, 2000.

Growth in stature in early, average, and late maturing children of the Caracas mixed‐longitudinal study

A sample of 113 boys and 101 girls of the Caracas Mixed‐Longitudinal Study was grouped into early, average, and late maturers according to selected cut‐off points of the 10th and 90th centiles for age at peak height velocity (APHV). Individual curves were fitted with the cubic spline function, in which height velocity corresponds to the first derivative. Age at menarche (AM) was estimated by recall in a longitudinal context. Differences between groups were assessed with F and t‐tests. Girls were approximately 2 years earlier than boys in APHV and thus significantly shorter; their estimated PHV was also significantly lower. APHV in boys and girls occurred 0.4–0.6 years earlier than in European children, which is consistent with a faster tempo of growth of Venezuelan youth. The three maturity groups differed significantly in timing, stature, and AM. Early maturers were taller than average maturers, and the latter were taller than late maturers with maximal differences between the extreme groups at ages 13–14 in boys and 11–12 in girls. Early maturers grew at a faster rate than average maturers, and the latter grew at a faster rate than late maturers up to 13 years in boys and 10–11 years in girls. Despite difficulties encountered in the analysis of mixed‐linked longitudinal data, meaningful growth differences were found between maturity groups of urban Venezuelan children.