Prevalence and predictors of subclinical atherosclerosis among asymptomatic “low risk” individuals in a multiethnic population

Background Current approaches to cardiovascular (CV) risk assessment have limitations. Subclinical atherosclerosis (SCA) as determined by carotid ultrasound is an independent predictor of myocardial infarction and stroke and can refine CV risk assessment. Objectives We aimed to determine the prevalence and predictors of SCA in a multiethnic population classified as low risk for coronary heart disease (CHD) events by the Framingham Risk Assessment Model. Methods We conducted a cross-sectional population study in 1015 Canadian adults of Caucasian European, South Asian, Chinese and Aboriginal ancestry. CHD risk was calculated by the 10-year Framingham Risk Score (FRS). Novel and conventional CHD risk factors were measured and high-resolution carotid ultrasound was performed. SCA was defined as carotid intima media thickness (IMT) ≥75th percentile adjusted for age, sex and ethnicity. Results Seven hundred and fifty two (74%) participants were classified as low risk by FRS. Of these, 175 (23%) had evidence of SCA. Independent predictors of SCA among low-risk subjects included female sex, systolic blood pressure, and apolipoprotein B. Conclusions Many individuals classified at low CHD risk by the FRS have SCA and are at increased long-term risk for vascular events. Carotid IMT can identify subjects with SCA, who may benefit from early intervention.