A secular trend in age at menarche in Sendai city and its surroundings.
A secular trend in age at menarche was examined for 1,333 women living in Sendai city and its surroundings by applying the birth-year cohort analysis and the cross-sectional probit analysis. The trend toward younger menarcheal ages was consistently observed by both analyses, and it started off soon after the second World War. The speed was 0.11 year/year for the observation period of 1946 to 1966.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D005260:Female; D006801:Humans; D007564:Japan; D008572:Menarche; D008875:Middle Aged; D012959:Socioeconomic Factors