Obesity accelerates secondary sexual maturity in girls

Background Worldwide incidence of obesity in children is increasing. Obesity may have many health effects including advancement of sexual maturity. Objective The aim of this study was to assess the timing of secondary sexual maturation in obese vs. non-obese girls. Methods Subjects were 105 obese and 105 non-obese girls, aged 7 to 8 years who had not entered puberty. Breast and pubic hair growth, secondary sexual characteristics, were assessed at baseline and every 4 months for two years. Onset of puberty was defined as Tanner stage for secondary sexual maturation of breast Tanner stage II (B2) and/or >= pubic hair Tanner stage II (P2). Survival analyses were used to estimate time to puberty in both groups. Cox regressions were used to analyze possible factors affecting secondary sexual maturation. Results Mean onset of breast budding (B2) was 7.8 (95% CI 7.7 to 7.8) years in obese girls vs. 8.6 (95% CI 8.5 to 8.6) years in non-obese girls (P<0.001). Mean onset of pubarche (P2) was 8.7 (95% CI 8.6 to 8.8) years in obese girls vs. 9.0 (95% CI 8.9 to 9.0) years in non-obese girls (P<0.001). Hazard ratios of obese girls to experience an earlier secondary sexual maturation at maturity level B2, B3 and P2 were 1,34 (95% CI 1.19 to 1,52), 6.91 (95% CI 3.90 to 12.24) and 3.78 (95% CI 2.42 to 5.89), respectively. Conclusions Obesity was associated with earlier Onset of puberty in girls. Obese girls entered puberty approximately 3 to 9 months earlier than their non-obese peers.