Combined hyperlipidemia in relation to race/ethnicity, obesity, and insulin resistance in the Multi-Ethnic Study of Atherosclerosis.

We have asked whether the prevalence of combined hyperlipidemia (CHL) differs by race/ethnicity, obesity, and insulin resistance in a contemporary, multiethnic, US cohort. We determined the prevalence and adjusted odds of CHL in a cohort of 5923 men and women free of clinically recognized cardiovascular disease and diabetes according to race/ethnicity (white, Chinese, African American, and Hispanic), obesity, and insulin resistance. Untreated lipid values were imputed for those on lipid-lowering therapy. Combined hyperlipidemia was defined using age- and sex-specific greater than or equal to 75th percentile cut points for low-density lipoprotein cholesterol and triglycerides obtained from a predominantly white North American population study. Compared with whites, adjusted odds ratios for CHL were 0.48 in African Americans (95% confidence interval [CI], 0.30-0.75), 1.33 in Hispanics (95% CI, 0.93-1.91), and 1.06 in Asians (95% CI, 0.62-1.82). Within the entire population, the adjusted odds of CHL were over 2-fold higher in overweight and obese participants compared with normal-weight participants and more than 4-fold higher in quartiles 2 through 4 of insulin resistance compared with quartile 1. African Americans had lower odds for CHL than whites despite higher body mass index and abdominal adiposity. Hispanics had a nonsignificantly higher trend, and Asians had no significantly different odds than whites. Modest increases in weight and insulin resistance were associated with significantly higher odds of CHL in a multiethnic US population. Further research is needed to determine the most efficacious diet, exercise, and drug management to decrease the risk of CHL and coronary heart disease among racial/ethnic groups in the United States.