Secular trend in age at menarche in China: A case study of two rural counties in Anhui Province

There is increasing evidence that age at menarche has decreased in Europe a nd the United States during the last century and in Japan over the last sev eral decades. Data from a community-based survey conducted in two rural cou nties of Anhui Province in China indicate a similar, downward secular trend in age at menarche for Chinese women. The present study shows the mean age at menarche decreased by 2.8 years, from 16.5 to 13.7, over an approximate 40-year time interval. This rapid decrease in age at menarche may partly b e due to better nutrition and living standards reflected by the improved so cioeconomic standards experienced in China over the past few decades. To te st this hypothesis, a number of determinants of age at menarche were assess ed; year of birth, literacy status, county of residence, amount of physical labour, general health status, pesticide exposure before age at menarche, and drinking water source were all found to be associated with age at menar che.