Association of Serum Lipids and Coronary Heart Disease in Contemporary Observational Studies

Background The use of statins increased among US adults with high coronary heart disease (CHD) risk after publication of the 2001 cholesterol treatment guidelines. Methods and Results We analyzed the association between lipids and CHD among 9578 REasons for Geographic And Racial Differences in Stroke (REGARDS) study participants and 346595 Kaiser Permanente Southern California (KPSC) members with baseline lipid measurements in 2003 to 2007. We performed the same analyses among 14590 Atherosclerosis Risk In Communities (ARIC) study participants with lipid measurements in 1987 to 1989. Analyses were restricted to blacks and whites 45 to 64 years of age without CHD who were not taking statins at baseline. Total cholesterol, high-density lipoprotein cholesterol, and triglycerides were measured at baseline. Low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and ratios of total to high-density lipoprotein cholesterol and triglycerides to high-density lipoprotein cholesterol were calculated. The prevalence of diabetes mellitus, history of stroke, and antihypertensive medication use increased at higher low-density lipoprotein cholesterol in ARIC but not in REGARDS or KPSC. Over 8.9 years of follow-up, 225 CHD events occurred in REGARDS, 6547 events in KPSC, and 583 events in ARIC. After multivariable adjustment, less favorable lipid levels were associated with higher hazard ratios for CHD in ARIC. These associations were attenuated in REGARDS and KPSC. For example, the hazard ratio associated with the highest versus lowest quartile of low-density lipoprotein cholesterol (146 versus 102 mg/dL) was 1.89 (95% confidence interval, 1.42-2.51) in ARIC, 1.25 (95% confidence interval, 0.81-1.92) in REGARDS, and 1.49 (95% confidence interval, 1.38-1.61) in KPSC. Conclusion The association between lipids and CHD in contemporary studies may be attenuated by the preferential use of statins by high-risk individuals.