The relationship between menarche age and anthropometric indices of girls in Sabzevar, Iran

Objective: To determine the relationship between anthropometric indices and the age of menarche in female students of Sabzevar, Iran. Methods: The cross-sectional study was conducted in Sabzevar, Iran, from April to September 2010, and involved girls of 11-18 years of age. The required sample size for analysing the relationship between menarche age and Body Mass Index was estimated to be 110 by correlation coefficient and Cox survival regression model and by using the NCSS_PASS software. The study had 130 students who were selected by multi-stage probability sampling. Relevant data were collected through a questionnaire as well as by measuring the anthropometric indices such as height, weight etc. Analysis of data was done by independent t-test, Pearson's correlation coefficient, Chi-square, Kaplan-Meier and Cox survival regression model using SPSS 15. Results: The mean menarche age was 12.5 +/- 1.4 years. Mean body mass index, weight and height of the menstruated girls were higher and significant than the corresponding figures of the non-menstruated girls. The correlation coefficient showed a significantly negative relation between body mass index and menarche age (r=-0.221, p=0.025), but correlation between menarche age and height or weight was not significant. Menarche occurrence rate was significantly higher in overweight girls than girls with normal weight. Menarche occurrence rate in girls with low weight was lower than those of normal weight. Conclusion: The menarche age and body mass index are significantly related; the higher body mass index, the lower was the menarche age, resulting in a higher menarche occurrence rate.