Secular Trends and Socioeconomic Differentials in Menarcheal Age for South Korean Women

In this study, we assessed the secular trends and socioeconomic differentials in menarcheal age among women aged 25-64 year.
Using the 5th Korea National Health and Nutrition Examination Survey (KNHANES, 2010-2012), bivariate analysis and one-way analysis of variance were used to test the statistical differences between age groups.
The mean age at menarche was 14.3 yr with a steep decrease in the younger cohort: from 15.9 yr in 1951-1955 to 13.1 yr in 1986-1990. Height as a proxy marker for early nutrition showed an inverse relationship with menarcheal age. The earlier menarcheal age patterns in women of higher socioeconomic position were observed according to one's education, monthly family income, occupation, region (urban vs. rural), and parental education.
This result suggests a fast and ongoing trend in age at menarche and the socioeconomic discrepancy among Korean women in the last four decades.