The incidence of early and precocious puberty of children in two Chinese cities: a multi-center prospective cohort study.

BACKGROUND

There are no population-based school cohort studies reporting the incidence of early and precocious puberty in China. This study aims to determine the incidence of early and precocious puberty in China.

METHODS

This prospective cohort study involved 8,025 children (4,341 boys and 3,684 girls) in China. Precocious puberty was defined as breast development stage II before 8 years or menarche before 10 years in girls, and testicular volume (TV) ≥ 4 ml before 9 years in boys. Early puberty was defined as breast development stage III between 8 and 9.8 years or stage IV between 8 and 12.4 years in girls, and TV ≥ 4 ml between 9 and 9.7 years or TV ≥ 12 ml between 9 and 11.9 years in boys. Incidence was stratified by age, sex, BMI, and district.

RESULTS

The adjusted incidence of precocious puberty was 1.7% (girls:2.9%; boys: 1.1%). Early puberty incidence was 3.9% (girls: 3.2%; boys: 4.5%). Urban boys had a higher incidence of early puberty (5.7%) compared to suburban boys (0.7%). Girls with overweight and obesity had higher incidences of early puberty (6.9% and 11.8%, respectively), with girls with obesity also showing a higher incidence of precocious puberty (4.6%).

CONCLUSION

The incidence of early and precocious puberty among children in these two Chinese cities was relatively high, particularly among girls. CLINICAL TRIAL NUMBER: Not applicable.