Familial aggregation of blood lipid response to exercise training in the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study

Background - Fasting levels of plasma lipids and lipoproteins are reported to improve with regular exercise training. However, little is known on whether the training responses are influenced by heritable factors. Methods and Results - The lipid profile was assessed in 115 black (224 individuals) and 99 white families (469 individuals), who participated in the HERITAGE Family Study, while in a sedentary state (baseline visit) and after exercise training for 20 weeks (post visit). Variables included total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (ApoB), high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I, and HDL-C subfractions 2 (HDL₂-C) and 3 (HDL₃-C). Familial correlations for the training responses (Δ=post-baseline) were significant for most variables, and the percent variance accounted for by familial factors (ie, maximal heritabilities) ranged from 25% to 38%. Exceptions were for higher heritabilities near 60% for ΔApoB in blacks and ΔHDL₂-C in whites and a lower estimate of zero for ΔLDL-C in blacks. Conclusions - Heritable factors in part determine lipid profile responses to regular exercise. Maximal heritabilities were similar across ethnic groups and variables, except for ΔLDL-C, ΔApoB, and ΔHDL₂-C. Molecular studies to identify the markers and genes associated with these influences are currently underway.