Factors Influencing Menarcheal Age: Results From the Cohort of Tehran Lipid and Glucose Study

BACKGROUND Menarche is considered as a milestone in the women's reproductive life. Most existing studies on factors influencing menarcheal age had cross-sectional designs and their finding were controversial. OBJECTIVES We aimed to determine some factors affecting the age at menarche in a cohort study with an average of ten-year follow-up; the study was conducted within the framework of Tehran Lipid and Glucose Study (TLGS). MATERIALS AND METHODS For the purpose of the present study, we recruited all the females aged 12 to 18 years participated in TLGS whose menarche had not begun at the initiation of the study, but occurred during their follow-up. The effect of premenarcheal status of various factors including socioeconomic and anthropometric parameters, physical activity, energy expenditure, and exposure to tobacco smoke on menarcheal age was explored. RESULTS The mean of age at menarche was 13.06 ± 1.24 years. There were significant statistical associations between age of the participants' mothers at menarche (r = 0.66, P < 0.001), maternal education (r = -0.04, P = 0.002), and body mass index (BMI) before menarcheal (r = 0.25, P = 0.027) with age at menarche. There was no significant correlation between age at menarche, with either of maternal employment, premenarcheal physical activity, energy expenditure, and passive smoking. CONCLUSIONS Among various factor influencing menarcheal age, premenarcheal BMI is modifiable, and considering its significance, could prevent early or late menarches.