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

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.