[Relation between age at menarche and final height of women in the Pró-Saúde Study]

To evaluate the relation between age at menarche and final height.

Complete data were obtained for 1,940 participants of a cohort study (Pró-Saúde Study) of civil servants at a university in Rio de Janeiro. A self-administered questionnaire was used to obtain the date of birth, age of the first menstruation and parents' educational level. Height in centimeters was measured twice by trained anthropometrists. Data were analyzed using linear regression models with final height as the dependent variable.

After adjusting for parents' educational level, it was observed that for each additional year in the age at menarche there was an increase in the final height of 0.91 cm for women aged 22 to 30 years, 0.44 cm for women aged 31 to 40 years and 0.40 cm for those between 41 and 50 years of age. In contrast, for women of 51 to 60 years of age, each additional year in the age at menarche was associated with a decrease of 0.64 cm in the final height. Focusing only on women between 22 and 50 years of age, no significant interaction was identified between age and age at menarche, however a strong negative confounding effect exerted by participants' age and by their parents' educational level was identified.

Results of this study suggest that, for younger generations, a later age at menarche is directly associated with final height. Childhood socioeconomic conditions and generation effects can be important confounding factors and should be considered in analyses of this relationship.