Background and Objective: Obesity is known to affect pubertal timing. However, existing data are still controversial, observing either delayed or accelerated pubertal onset, especially among boys. Herein, we evaluated pubertal milestones and underlying hormonal changes between lean and obese children.
Material and Methods: We examined 13,484 events from 4,855 lean (BMI SDS <1.28) and 1,983 obese (BMI SDS > 1.88) children aged 5 to 20 years. The onset of pubertal milestones (breast stage (B)≥2, pubic hair stage (PH)≥2, testicular volume≥4ml, age of menarche) was analyzed by both survival analysis (encompassing interval-censored, right- and left-censored data), as well as direct comparison of prepubertal vs. pubertal events within a one-year-resolution. Observations were compared with dynamics of puberty-related hormone levels.
Results: Among girls with obesity, the estimated median onset of thelarche was 9.86 years, compared with 10.18 years in lean girls. Furthermore, 13.9% of obese girls exhibited already breast development (B≥2) at the age of 7 years, compared with only 1.2% of lean girls. In addition, obesity reduced the average age of menarche about 6 months (12.22 (±1.30) vs. 12.76 (±1.18) years). Surprisingly, those differences were not paralleled by altered estrogen or gonadotropin levels. However, earlier development of pubic hair among obese vs. lean girls (15.3% vs. 0% had PH≥2 at the age of 7 years) was associated with higher testosterone and DHEA-S levels within the same age group.
Regarding boys, no clear association between BMI and the onset of testicular growth could be observed. On the other hand, development of pubic hair started earlier comparing obese boys with lean peers (6.4% vs 2.7% with PH≥2 at 8 years of age) and was associated with increased DHEA-S levels but no difference in testosterone levels.
Conclusion: Pubertal milestones were accelerated among girls with obesity when compared with lean peers. No clear association of BMI and pubertal onset (gonadarche) could be detected for boys. Pubarche occurred earlier among both obese girls and boys and was associated with higher DHEA-S levels. Those findings should be kept in mind, when distinguishing between physiological and pathological patterns of pubertal development among children with obesity.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology