Contribution of genes to the changes on body composition components: A two-year longitudinal study in a small cohort of twins

Context. High heritability of body composition variables is well-known, however, longitudinal effect of genes is still unclear. Objective. The aim of this study was to investigate the pattern of longitudinal changes in anthropometric variables in a small cohort of twins. Design. Longitudinal classical twin study, performed in 2009 and in 2011 on the same twin pairs. Subjects and Methods. Eighteen healthy adult Hungarian twin pairs (13 monozygotic [MZ], 5 dizygotic [DZ]; mean age 54.0 ± 15.2 years; average body mass index 24.4±5.4 kg/m² in 2009 and 25.1±4.7 kg/m² in 2011, respectively) recruited from the Hungarian Twin Registry underwent bioimpedance analysis (OMRON). Results. Significant, higher positive intrapair correlations were detected in the longitudinal change in weight (p<0.05), body fat mass (p<0.01), non-fat mass (p<0.01), and body mass index (p<0.01) in MZ compared to DZ twins, suggesting the possibility of longitudinal genetic determinants. Negative associations were observed with regard to the two-year change in waist and hip circumferences, suggesting the longitudinal role of environmental factors in these phenotypes. Conclusions. The findings of the present human twin study suggest that weight, body fat mass, non-fat mass, and body mass index are determined genetically and longer exposure to pathologic environmental factors is necessary to elicit alterations in the regulation of these parameters. Longer-term confirmation in a larger sample is required to confirm these results.