[Epidemiologic study on current pubertal development in Chinese school-aged children]

Abstract

Objective: To survey the current status of pubertal development of Chinese children and to compare the precocious puberty prevalence of different regions.

Methods: A cross-sectional epidemiological study was conducted on 18 707 children and adolescents aged 6≊18 y with male/female ratio of 9 812/8 895 from 6 representative geographical areas in China, including Beijing, Tianjin, Hangzhou, Shanghai, Chongqing and Nanning. The height, weight, waist circumference (WC), hip circumference(HC) and sexual maturation states (Tanner stages: breast stages for girls and testicular volume for boys) of children and adolescents were measured. Probit analysis was used to calculate the median age and 95% confidence interval (CI) for onset of breast and testicular development. The prevalence of precocious puberty of different regions and BMI, waist circumference of different groups were compared.

Results: Breast development before 8 y was observed in 2.91% of girls, and testicular volume 4 ml or more before 9 y was observed in 1.74% of boys. The median age of onset of Tanner stages 2 for breast development in girls was 9.69 y (95% CI: 9.63≊ 9.75); the median age of onset of puberty as indicated by Tanner stages 2 for testicular development in boys was 11.25 y (95%CI:11.19≊ 11.30). The prevalence of precocious puberty (43 girls and 37 boys) was 0.43% (80/18 707). The prevalence of precocious puberty in northern region was higher than that in southwest region (0.736% compared with 0.282% P<0.05). There was no difference in onset age of precocious puberty in girls among three regions; but the onset age of precocious puberty in boys was earlier in east China [(7.4±0.28)y]. The SD values of BMI and waist-to-hip ratio (W/H) in precocious puberty children were higher than those in the peer normal children. There was no difference in BMI,waist circumference and waist-to-hip ratio in the precocious puberty children among different regions.

Conclusion: The current diagnostic criteria of precocious puberty are suitable for the children in the survey areas. The prevalence and the onset age of precocious puberty are various in different regions. A positive association between obesity and precocious puberty is found both in boys and girls.