Change in age distribution of menarche and first spermorrhea among students in Guangdong province

Objective To examine the distribution and change of median age at menarche(MAM) and median age at first spermorrhea(MAFS) among students in Guangdong province and to provide basis for health education polices and measures.Methods Based on the data collected from the Surveys on Guangdong Students' Constitution and Health carried out from 1991 to 2010,MAM and MAFS were caculated by probit regression method.Results In 2010,the urban students' MAM was generally earlier than rural students;in undeveloped regions,MAFS was earlier in urban than in rural areas;while in developed regions,MAFS was earlier in rural areas than in the urban.There was a delay of 0.25 year in MAM and 0.60 year in MAFS in 2000 compared to those in 1991.Compared with those in 2000,an advance of 0.85 year in MAM and 0.44 year in MAFS were found in 2010.In 2010,MAM decreased by 0.60 year while MAFS increased by 0.16 year compared to those in 1991.Conclusion In Guangdong province,the students' MAM and MAFS are different between urban and rural area.Within the 19 years,there is a decreasing trend in MAFS for male students and an increasing trend in MAM for female students in Guangdong province.