Age at menarche and indigenous ancestry. A population study in Chile Edad de menarquia y ascendencia indígena. Un estudio poblacional en Chile

Abstract

Background: The age at menarche may influence decisively health and disease in women. It also indicates the beginning of the reproductive period and, as a consequence, the possibility of biological continuity for the human species. Genetic and environmental determinants define the age of menarche and can explain differences found among different populations. Aim: To determine the age at menarche among adolescents with different levels of indigenous descent (parental indigenous surnames), considering the effect of socioeconomic and demographic factors. Material and Methods: An observational study of historic cohorts of 8.624 girls from the Araucanía Region (central-southern Chile) was carried out. Data were collected by health professionals using a previously validated questionnaire. Occurrence of menarche was estimated through survival analysis and compared between groups (according to indigenous parental surnames) adjusted for parents' income and educational level and provenance (rura