Familial Resemblance in Physical Activity

Abstract

Scientific evidence demonstrates that regular physical activity reduces the risk of morbidity and mortality from a number of chronic diseases. In order to implement appropriate strategies for the promotion of physical activity, it is important to understand the factors explaining the wide variation of physical activity levels in the population. In addition to social and physical environment, demographic and psychological factors, familial factors, both genetic and environmental, may also play a role. PURPOSE: To investigate familial resemblance in physical activity and to determine if this could be best explained by genetic and/or environmental factors. METHODS: 292 Flemish families (271 fathers, mean age 45 yrs; 243 mothers, mean age 42 yrs; 238 sons, mean age 15 yrs; 195 daughters, mean age 14 yrs) participated in the Flemish Longitudinal Offspring Study (FLOS) conducted within the framework of the Policy Research Centre Sport, Physical Activity and Health. Physical activity was assessed using the Flemish Physical Activity Computerized Questionnaire (FPACQ). Pearson correlations were used to investigate resemblance between family members. To further explore these familial correlations underlying variance components models were tested using model fitting techniques. RESULTS: Several significant and moderate correlations were found between parents (0.16–0.30), parent-offspring (0.14–0.36) and siblings (0.16–0.52). Generally, significant similarities between parents (0.16–0.30) and between siblings (0.24–0.52) were higher than between parent-offspring (0.15–0.36). For almost all variables, a model including common environmental (Vc) and unique environmental (Ve) factors explained most of the observed variability in physical activity. Only for time per week spent on vigorous sports and on moderate activities, an additional genetic factor (Vg) further improved the model fit. Maximal transmissibility (Ve + Vg) ranged from 7% for frequency per week of moderate activities to 23% for time spent watching TV. This could be completely explained by Vc, except for time per week spent on vigorous sports and on moderate activities where also a Vg of respectively 4% and 11 % was estimated. CONCLUSIONS: The RESULTS of this study suggest familial resemblance in several dimensions of physical activity. For most physical activity variables the maximal transmissibility could be completely explained by common environmental factors. This is an important finding in the light of the development of effective strategies for the prevention of inactivity.