Impact of optimal cholesterol levels on subclinical atherosclerosis in the absence of risk factors in young adults.

BACKGROUND AND AIMS: We aimed to assess the association of blood lipids with the prevalence, incidence, and progression of subclinical atherosclerosis among young individuals without dyslipidemia and other traditional cardiovascular risk factors (CVRFs).

METHODS: A total of 1270 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study aged 32-46 years free of cardiovascular disease, diabetes, hypertension, current smoking, and dyslipidemia (total cholesterol [TC] ≥ 240 mg/dL, triglycerides [TG] ≥ 150 mg/dL, low-density lipoprotein cholesterol [LDL-C] ≥ 160 mg/dL, high-density lipoprotein cholesterol [HDL-C] < 40 mg/dL, or taking lipid-lowering medications) were included. A subgroup with optimal lipids within the low-CVRF group was defined with TC < 200 mg/dL, LDL-C < 100 mg/dL, non-HDL-C < 130 mg/dL, and women with HDL-C ≥ 50 mg/dL.

RESULTS: 1-SD higher TC (25.9 mg/dL), LDL-C (24.7 mg/dL), and non-HDL-C (26.6 mg/dL) were associated with a greater risk of presence (hazard ratios: 1.30-1.36), incidence (1.30-1.32), and progression (1.31-1.35) of coronary artery calcium (CAC) and a 42-44% greater odds of composite mean carotid intima-media thickness (CIMT) ≥ 75th percentile [780 μm] (p < 0.05). Repeating the analyses in a subset of participants with a CAC score of zero did not alter the association of TC, LDL-C, and non-HDL-C with CIMT. In the subgroup with optimal lipids, these lipid indices remained associated with an increased risk of presence and incidence of CAC and greater CIMT measures.

CONCLUSIONS: Among adults aged 32-46 years, in the absence of traditional CVRFs, elevated cholesterol levels, even within what is considered optimal, are associated with atherosclerosis and arteriopathy.