Secular trend and social variation in age at menarche among Polish schoolgirls before and after the political transformation.

OBJECTIVES: To describe the biological results of the political and economic transformations that took place in Poland between 1966 and 2012, based on an analysis of age at menarche, and to determine changes across social groups.

METHODS: Data were collected in 1966, 1978, 1988, and 2012 in several districts of Poland. The study included 34,940 schoolgirls. Age at menarche was assessed with the use of status quo method. Definition of socioeconomic status was based on 4 factors: urbanization level, mother and father education, and family size.

RESULTS: When the political and economic situation in Poland improved, a decrease in age at menarche was observed, whereas in years of crisis it increased. The same social differentiation in menarcheal age observed before the political transformation continued to be present in 2012.

DISCUSSION: Socioeconomic changes were significantly associated with age at menarche. Social inequalities, reflected in menarcheal age, continue to be present in Poland.