Prevalence of precocious puberty among Chinese children: a school population-based study.

Purpose: To investigate the prevalence of precocious puberty in school-based population in Zhongshan, Guangdong, China.
Methods: We recruited a total of 4058 students in grades 1-3 using a multistage stratified cluster random sampling method in a population-based cross-sectional study. We evaluated height, weight, and development of breast and pubic hair in girls, breast development was evaluated by inspection and palpation combined with ultrasound detection for overweight and obese girls, and testicular volume and development of pubic hair in boys. We estimated overall, sex-, age, and district-specific prevalence of precocious puberty and examined the association between prevalence of precocious puberty and body mass index (BMI).
Results: The unadjusted and adjusted prevalence of precocious puberty by Tanner stage was 4.74% (girls:8.78%, boys:2.58%) and 6.19% (girls:11.47%, boys:3.26%), respectively. In both urban and suburban areas, the prevalence of precocious puberty was higher in the overweight and obese group than in the normal-weight group (p < 0.05). The prevalence of precocious puberty among overweight (27.94%) and obese (48.00%) girls was higher than that of normal-weight girls (8.73%) (p value for trend < 0.05). In boys, the prevalence of precocious puberty in the obese (6.78%) group was higher than that in the normal-weight (2.86%) group (p < 0.05).
Conclusions: The prevalence of precocious puberty was high in China. Overweight and obesity was related to precocious puberty, but this correlation had gender differences and may be affected by other environmental factors.