Familial aggregation of aerobic power: the influence of age, physical activity, and body mass index

Whereas modest familial aggregation of VO2max has been documented after controlling for variables such as physical activity habits, the effect of adjustment for moderating variables has not been directly tested. This issue was addressed in 95 Anglo and 111 Mexican-American families who underwent submaximal cycle ergometer testing. Zero-order correlations of predicted VO2max between pairs of family members were generally weak for both Anglo families (r = 0.04 to 0.35) and Mexican-American families (r = 0.03 to 0.50). Five of 12 correlations were significant. Similar results were found for combined ethnic groups. Adjustment for age, physical activity, and body mass index by partial correlation had few significant effects on aggregation of predicted VO2max. Adjustment for body mass index produced significant decreases in the correlation for Anglo spouses and mother-older child and sibling pairs in the combined group. Although influential moderating variables were not identified, body mass index was found to be a significant, though inconsistent, mediator of aggregation of VO2max. Genetic factors were not strongly supported because of generally weak aggregation in the two ethnic groups.