Secular Trends in the Median Age at Menarche and Spermarche Among Chinese Children From 2000 to 2019 and Analysis of Physical Examination Indicators Factor.

Abstract

This research aimed to understand the long-term trends in the age of menarche among girls and spermarche among boys, and to analyze the factors that may influence the onset of menarche and first spermarche. The study was based on data from 49 566 students in Henan Province collected from the Chinese National Surveys on Students' Constitution and Health (CNSSCH) conducted between 2000 and 2019. Median age at menarche and spermarche was estimated by probit analysis. t-Tests were used to analyze the influence of menarche and first spermarche on physical examination indexes of adolescent children, and the chi-squared test was used to compare whether the differences in physical activity were statistically significant. The age at menarche has decreased from 12.33 years in 2000 to 12.00 years in 2019, and the age at first spermarche has decreased from 14.01 years in 2000 to 13.99 years in 2019. The age at first spermarche in urban boys (13.61 years in 2000; 12.94 years in 2014) was consistently younger than that in rural boys (14.43 years in 2000; aged 13.08 in 2014), except in 2019. The age of menarche in urban girls (12.23 years in 2000; 11.89 years in 2019) was always earlier than that in rural girls (12.44 years in 2000; 12.05 years in 2019). The age at menarche and spermarche for children in Henan Province generally showed a decreasing trend from 2000 to 2019. The status of BMI is significantly associated with the early onset of puberty in children.