NEW ORLEANS — Measuring non-HDL cholesterol level may be a better primary screen for risk of first nonfatal myocardial infarction in women than measuring the level of LDL cholesterol, reported Wildon R. Farwell, M.D.
LDL cholesterol has long been considered the most atherogenic lipoprotein, but recent studies have implicated other types of cholesterol, including triglyceride-rich very low-density-lipoprotein cholesterol and intermediate-density-lipoprotein cholesterol—both of which are included in the non-HDL measure, Dr. Farwell said at the annual meeting of the Society of General Internal Medicine.
He and his colleagues at Brigham and Women's Hospital, Boston, analyzed data from a cohort of nearly 19,000 women from the Women's Health Study who neither had a diagnosis of hyperlipidemia nor took cholesterol medication. They performed direct-measurement assays for lipid parameters and collected baseline self-reported risk factors at enrollment. They confirmed 118 self-reported cases of first nonfatal MI and used Cox proportional hazards models to compare the independent associations of non-HDL cholesterol and LDL cholesterol with MI risk, adjusting for cardiovascular risk factors.
The mean values of LDL and non-HDL cholesterol in the 118 MI patients were 116.3 mg/dL and 147.5 mg/dL, respectively. Non-HDL cholesterol level was a more significant predictor of risk than LDL cholesterol level. “The hazard ratio for the highest tertile [of non-HDL cholesterol] was 2.91, compared with 1.51 for LDL,” Dr. Farwell said. Similarly, the hazard ratios for the middle non-HDL and LDL tertiles were 1.81 and 0.92, he reported.
The non-HDL tertile measures were defined as less than 130.1 mg/dL, from 130.1 to 159.4 mg/dL, and greater than 159.4 mg/dL. For LDL cholesterol, the tertile measures were defined as less than 102.1 mg/dL, from 102.1 to 126.6 mg/dL, and greater than 126.6 mg/dL.
“While LDL cholesterol is important, non-HDL cholesterol may be the more important predictor, at least in some groups of people,” Dr. Farwell said.