Differences in body composition between pre-menarcheal and menarcheal Bengalee Hindu girls of Madhyamgram, West Bengal, India

Abstract

A study on 111 pre-menarcheal (PMG) and 123 menarcheal (MG) Bengalee Hindu girls was undertaken to compare differences in their anthropometric and body composition characteristics. The mean ages of the PMG (12.5 years, SD = 1.2) and MG (12.6, SD = 1.1) subjects were similar. Anthropometric measurements included height, weight, triceps, and calf skinfolds. Two derived indices (body mass index [BMI] and sum of skinfolds) and four body composition measures, percent body fat (PBF), fat mass (FM), fat free mass (FFM), and fat mass index (FMI) were also studied. The mean, 25th, 50th, and 70th percentile values of age at menarche were 12.0, 11.1, 12.0 and 12.9 years, respectively. Results showed that MG had significantly (P < 0.001) higher mean values for all anthropometric and body composition variables. The difference in mean height, weight, and BMI were 10.5 cm, 11.0 kg, and 3.0 kg/m2, respectively. The differences between the two groups in mean PBF, FM, FFM, and FMI were 7.7%, 5.1 kg, 5.9 kg, and 2.0 kg/m2, respectively. The percent difference (after attainment of menarche) in mean FM and mean FFM were 50.5% and 19.9%, respectively. Multivariate regression analyses revealed that attainment of menarcheal status had significant impact on all four measures of body composition (PBF: P < 0.0001; FM: P < 0.0001; FFM: P < 0.0001; FMI: P < 0.001) independent of BMI. Using BMI as a covariate, results of ANOVA revealed that the mean values of PBF, FM, FFM, and FMI were significantly higher among MG compared with the PMG subjects, even after adjustment for BMI. In conclusion, this study clearly indicated that there existed significant differences in body composition, irrespective of BMI, between MG and PMG Bengalee Hindus. It also demonstrated that relative difference in mean FM was significantly greater, compared to the relative difference in mean FFM, after the attainment of menarche.