Dependence between age at menarche, body composition and selected somatic indices

The aim of this paper is to analyse age at menarche in Tanzanian girls for associations with body composition and selected somatic indices. The study included 97 girls (71 post-menarche and 26 pre-menarche). Measurements were taken of: body height, body weight, waist and hip circumferences. Body composition was measured: percentages of H2O, fat, and muscle mass in the body. The girls’ nutritional status and body fat distribution were assessed according to the following somatic indices: BMI, WHR (Waist-to-Hip Ratio) and WHtR (Waist–to–Height Ratio). For the post-menarcheal group n=71, backward stepwise multiple regression analysis was performed. Age at menarche calculated using the recall method n=71 amounted to X=14.29 years, calendar age X=15.92 years. More than half (57.69%) of the girls before menarche had not reached the body weight of >48kg, whereas in the post-menarche group they accounted for 32.39%. As many as 97.18% of the post-menarche girls had body fat content of >22% , compared to 88.46% among the pre-menarche group. According to BMI, 74.65% of post-menarche girls had healthy weight, and 73.08% in the pre-menarche group. There were no significant differences in WHR or WHtR. It may indicate similar fat distribution in girls prior to menarche, as well as those who already menstruate. The analysis shows that the onset of menstruation is not strictly dependent on reaching a critical point in body weight or body composition.