Approximately 1500 individuals who were examined in the BHS on at least three separate occasions over a period of up to 20 years, and who consented to participate in studies of genetic factors influencing CVD risk, will have genotypes measured at selected loci either known or strongly suspected to affect interindividual variation in CVD risk. Longitudinal multilevel regression will be used to measure the effects of variation at these loci on quantitative CVD risk factor profiles within individuals and to determine whether some gene effects on CVD risk variation are age-dependent.