Little information is available on the association between cholesterol levels and cardiovascular disease (CVD) and coronary heart disease (CHD) mortality in people with a low 10-year risk of atherosclerotic CVD, as determined by risk assessment equations. Statin therapy for this population is not currently recommended, unless low-density lipoprotein (LDL) cholesterol levels are 190 mg/dL or higher.

Researchers evaluated the associations of LDL cholesterol and non-high-density lipoprotein (non-HDL) cholesterol levels with CVD and CHD mortality in patients who have a low 10-year risk of atherosclerotic CVD. Participants were deemed to be low risk if they had an estimated 10-year atherosclerotic CVD risk of < 7.5%; exclusion criteria included having a history of CVD, diabetes, or triglyceride levels = 450 mg/dL. Of the 36,375 participants, 72% were men. The median age of participants was 42, and the median 10-year estimated atherosclerotic CVD risk was 1.3%. Median follow-up was almost 27 years. Anyone who died within one year of the first lipid measurement was not included in the data analysis.

After adjusting for age, increasing LDL cholesterol levels were significantly associated with increased risk of CVD and CHD mortality. In unadjusted analyses, LDL cholesterol levels >= 100 mg/dL were associated with a >= 30% increase in relative risk of CVD death compared with LDL cholesterol levels < 100 mg/dL, and LDL cholesterol categories >= 130 mg/dL were associated with a >= 50% increase in relative risk of CHD death. In multivariable analyses, significant associations with CVD and CHD death persisted for LDL cholesterol >= 160 mg/dL.

The researchers note several limitations of the study. It's not known whether participants were taking lipid-lowering drugs at the start of the study or whether they began drug treatment during the study. Also, the study group was of higher socioeconomic status than the general U.S. population. Finally, the study was not designed to provide direct evidence that lower LDL cholesterol levels improve outcomes in this population.

Further study is needed to determine whether low-risk individuals with elevated LDL cholesterol and non-HDL cholesterol would benefit from lipid-lowering lifestyle modifications and drug therapy, the authors conclude.

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