Background & Objectives: Puberty is the process of sexual maturation and rapid growth that separates childhood from adulthood. Menarche, as a milestone, is the most important characteristic of adolescent girls students associated with psychological and social changes. The age at menarche varies by race and country of living, but changes in lifestyle, nutrition, body mass index, level of physical activity, family structure, socioeconomic status, and improvement in general health affect its onset. Because of the changes in the age of menarche over time, it is important to study it at different time intervals. Also, it is not clear about the difference between the age of menarche, its presence, and extent in adolescent girls in Tehran City, Iran, and its relationship with socioeconomic status. The present study investigated the distribution of menarche age and its relationship with socioeconomic status among female students aged 10 to 16 years in Tehran.
Methods: The present study was cross–sectional and descriptive correlational. The statistical population of the research was made up of female students aged 10–16 years in Tehran in the academic year of 2019–2020. So, 2302 students were randomly selected from the educational districts of Tehran, and of them, 2152 students answered the questionnaire completely and met the inclusion criteria for the study. The inclusion criteria were physical and mental health, as stated by the participants. The information of the present study was collected by a self–designed structured questionnaire that includes personal information, socioeconomic status (parental education level, family income, and family socioeconomic level), sports history, menarche status, and the exact age that occurred. Linear regression analysis test was used to investigate the relationship between menarche age and socioeconomic status. To describe and explain the age of menarche based on the predictor variables of physical activity and socioeconomic status (including parental education level, family socioeconomic level and family income level) used from univariate linear regression to predict a dependent variable (menarche age) by an independent variable (one of the variables of physical activity and socioeconomic status) and from multiple linear regression to predict the dependent variable (menarche age) by several independent variables (physical activity and socioeconomic status). All information in the questionnaires was calculated and analyzed by Excel (2016) and SPSS (version 23) software. The significance level in all cases was considered less than 0.05.
Results: According to the findings of this study, among 2152 eligible females, 1446 (67.2%) had experienced menarche. The mean ± SD age at menarche was 12.09±1.07 years. Based on the results of the Spearman correlation coefficient, the mother's education level (p=0.041) and the father's education level (p=0.043) had a significant relationship with girls' menarche age. However, the age of menarche was not significantly related to the socioeconomic status of the family (p=0.333), family income (p=0.295), and physical activity (p=0.797). Among the variables related to the menarche age, the multiple regression model introduced only the father's education level variable as the most important predictor variable, which had the highest correlation with the menarche age, and 0.3% (R²=0.003) of the changes in the girls' menarche age to dedicated itself. The results of the standardized beta coefficient indicated that there was a negative and significant relationship between the two variables of menarche age and the father's education level (p=0.025, Beta= –0.065).
Conclusion: The results of the present study showed that the mean age of menarche in this study was lower than in the previous study in Tehran girls. Also, the parental education level, especially the father’s education level, can provide favorable living conditions at the age of 10 to 16 years. Therefore, it is important to pay special attention to girls whose fathers have a high level of education to prevent early menarche by adjusting the environmental factors associated with menarche age.