Difference In Mean BMI Research Articles

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

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.

Meta-analysis of the association of the Trp64Arg polymorphism in the beta3 adrenergic receptor with body mass index.

As a result of efforts to isolate obesity-promoting genes, the Trp64Arg polymorphism in the beta3 adrenergic receptor locus, has been studied by many investigators. Results of the studies have varied in statistical significance and magnitude of the association of the polymorphism with body mass index (BMI: kg/m2). This has led to controversy about whether this polymorphism is associated with meaningful changes in BMI. To clarify the possible association, we conducted a meta-analysis. Meta-analytic study. For each genotype of the beta3 adrenergic receptor (Trp/Trp; Trp/Arg; Arg/Arg), we extracted the number of subjects, mean and standard deviation of BMI from 23 studies, including 36 different subgroups with a total of 7399 subjects. Other indices and obesity-related variables were not considered. No significant association of the Trp64Arg polymorphism with BMI was found. The weighted mean BMI difference between Trp/Trp homozygotes and Trp/Arg heterozygotes was 0.19 (s.e. = 0.11; P = 0.07). In addition, the distribution of effect sizes was not significantly heterogeneous (chi2=38.68; df 35; P = 0.31) suggesting that the variation of the effect sizes across the subgroups is not significant. A further weighted regression analysis, utilizing all three genotypes and adjusting for the random subgroup effect, also showed the effect of the polymorphism on BMI is not significant (F = 1.72, df = (2,54), P = 0.19). Based on existing data, the Trp64Arg polymorphism does not appear to be significantly associated with BMI. Moreover, we found no evidence for effect heterogeneity, suggesting that the effect of the polymorphism is not moderated by ethnicity or diabetic status.