The pubertal transition in 179 healthy Danish children: associations between pubarche, adrenarche, gonadarche, and body composition.

BACKGROUND: Pubertal onset is usually defined by breast development in girls and testicular growth in boys. Pubarche is defined as the attainment of pubic hair and is considered as a sign of pubertal transition. Pubarche is preceded by a gradual increase in production of adrenal androgens, DHEA and Δ4-androstenedione (Adione), a process termed adrenarche.
OBJECTIVE: To study the natural course of pubertal transition and the associations with adrenarche, body fat, and linear growth. DESIGN AND METHODS: A longitudinal study of 179 healthy children (89 girls) with higher socioeconomic background examined every 6 months for 5 years. Pubic hair stage, breast stage, genital stage, testicular volume (TV), height, weight, and four skinfolds were measured.
RESULTS: In girls, median age (25th and 75th percentiles) at thelarche (B2+) was 10.1 years (9.3-10.9). In boys, median age at attaining a TV >3 ml was 11.5 years (10.9-12.0). Median age at pubarche (PH2+) was 10.9 years (10.3-11.4) in girls and 11.6 years (10.8-12.4) in boys. Only 6.8% (4/59) of the girls and 24.6% (15/61) of the boys developed pubic hair as the first isolated sign of puberty. Serum DHEAS and Adione increased with age, although the increase in Adione was most pronounced in girls. No associations between early age at thelarche/testicular growth and increased body fat (BMI and sum of four skinfolds) were observed.
CONCLUSION: Danish children rarely experience pubarche as the first sign of puberty. No associations between age at pubertal onset and body composition were found. Circulating levels of Adione, but not DHEAS, increased with the onset of puberty, although with large interindividual variability.