Background: It is commonly recognized that physical activity has familial aggregation; however, the genetic\r\ninfluences on physical activity phenotypes are not well characterized. This study aimed to (1) estimate the\r\nheritability of physical activity traits in Brazilian families; and (2) investigate whether genetic and environmental\r\nvariance components contribute differently to the expression of these phenotypes in males and females.\r\nMethods: The sample that constitutes the Baependi Heart Study is comprised of 1,693 individuals in 95 Brazilian\r\nfamilies. The phenotypes were self-reported in a questionnaire based on the WHO-MONICA instrument. Variance\r\ncomponent approaches, implemented in the SOLAR (Sequential Oligogenic Linkage Analysis Routines) computer\r\npackage, were applied to estimate the heritability and to evaluate the heterogeneity of variance components by\r\ngender on the studied phenotypes.\r\nResults: The heritability estimates were intermediate (35%) for weekly physical activity among non-sedentary\r\nsubjects (weekly PA_NS), and low (9-14%) for sedentarism, weekly physical activity (weekly PA), and level of daily\r\nphysical activity (daily PA). Significant evidence for heterogeneity in variance components by gender was observed\r\nfor the sedentarism and weekly PA phenotypes. No significant gender differences in genetic or environmental\r\nvariance components were observed for the weekly PA_NS trait. The daily PA phenotype was predominantly\r\ninfluenced by environmental factors, with larger effects in males than in females.\r\nConclusions: Heritability estimates for physical activity phenotypes in this sample of the Brazilian population were\r\nsignificant in both males and females, and varied from low to intermediate magnitude. Significant evidence for\r\nheterogeneity in variance components by gender was observed. These data add to the knowledge of the physical\r\nactivity traits in the Brazilian study population, and are concordant with the notion of significant biological\r\ndetermination in active behavior.
Loading....