Investigating Puberty Onset and Its Relationship with Body Mass Index in Boys from Sabzevar, Iran

Background and Evaluation of puberty stages is important to assess adolescent health. This study has been done with the aim of determination of the average age of onset of puberty and its relationship with Body Mass Index (BMI) in male students of Sabzevar city in the North East of Iran in 1390. Methods and Materials: This cross - sectional study was conducted on 252 male students of secondary schools and high schools of Sabzevar, Iran, with the age of 11-18 years who were selected by probability and multistage sampling. Data were collected through a Tanner standardized questionnaire; afterwards, measuring of height and weight and BMI calculation were performed. Data were analyzed in SPSS 15 using chi-square test, t-test, ANOVA and Bonfronie post hoc test, analysis of covariance, Spearman correlation coefficient and Kappa agreement coefficient; significance level was considered as 0.05. To conduct this study, we selected a group of researchers who were trained for the initiation of project for assessing puberty in male schools in order to increase the accuracy of determining the Tanner stages. Students were examined for their height and weight, size of penis and testicles, and the manner of pubic and axillary hair growth as well as also voice changes. Mean final growth stage of testicles and scrotum (G5 stage), pubic hair (P5 stage), were measured to be 16.40 ± 1.65 and 16.79 ± 1.19 years respectively, and their mean BMI at P2 and G2 were 20.96±4.1 and 19.49±3.66 kg /m2 respectively. Regarding to the declining age of puberty and its relationship with BMI, health systems should focus on training programs and encouraging teenagers to begin changing their lifestyle. Age of puberty onset in male students is similar to many other countries but determining the precise status of puberty in Iranian children requires further studies in different provinces, rural and urban areas as well as longitudinal studies.