Age at Menarche and Its Related Factors Among Students of Qaen, Eastern Iran: A School-Based Cross-Sectional Study

Age at menarche is the key indicator of puberty in females and the reflector of populations’ health that different hereditary and environmental factors can affect it. This study was conducted to determine the age at menarche and its relationship with body mass index (BMI) and demographic factors among students of Qaen, Eastern Iran. This cross-sectional study was conducted on 400, 10 - 16-year-old students of Qaen located at the East of Iran, in 2016. The participants were selected by the random multistage sampling of students in elementary and secondary schools that were eligible to participate in the study. Data collection was carried out through interviews and a checklist including demographic and menarche information as well as height and weight measurements in schools. The data were analyzed using SPSS V. 18 by Pearson’s correlation, t-test, and multiple linear regression. The mean age of students was 13.86 ± 1.10 years, mean BMI was 20.38 ± 2.72 kg/m2 and the mean age at menarche was 12.78 ± 1.23 (95% CI: 12.66 - 12.90) years. There was an inverse correlation between the age at menarche and BMI (r = -0.123, P = 0.014) while the height (r = 0.195, P = 0.0001), maternal age (r = 0.223, P = 0.0001), and sleep duration (r = 0.156, P = 0.002) were directly related to age at menarche. No significant relationship existed between age at menarche and weight of students (P = 0.86). The mean age at menarche of students was as average as Iranian studies. Lower age at menarche was significantly correlated with higher BMI.