Prevalence and risk factors of carotid intima-media thickness in asymptomatic individual subjects in a tertiary care center in India

BACKGROUND: Carotid intima-media thickness (IMT) is increasingly identified as a marker of atherosclerosis and increased risk of cerebrovascular disease. AIM: We aimed to investigate the prevalence of carotid IMT in asymptomatic Indian individuals, more than 40 years of age, and correlate it with other risk factors for cerebrovascular ischemia. MATERIALS AND METHODS: Individuals attending outpatient services of Nizam's Institute of Medical Sciences, who were asymptomatic for cerebrovascular ischemia underwent detailed history and carotid Doppler examination. IMT on mid common carotid artery (CCA) was measured. All subjects’ blood was taken for biochemical estimation of fasting blood sugar and total cholesterol levels. RESULTS: Out of 1,392 subjects, 571 (41%) had abnormal IMT and 821 (59%) had normal IMT. On comparison of the two groups, the factors significantly associated with abnormal IMT were mean older age (59 vs 50.7 years; P < 0.0001) and higher prevalence of hypertension (257 (45%) vs 236 (28.7%); P < 0.0001), diabetes (159 (27.8%) vs 139 (16.9%); P < 0.0001), and hypercholesterolemia (124 (21.7%) vs113 (13.7%); P = 0.0001). After adjustment with multiple logistic regression, significant predictors were age (odds 3.2; 95% confidence interval (CI) 2.5-4.1), male gender (odds 1.5; 95% CI 1.1-1.9), hypercholesterolemia (odds 1.5; 95% CI 1.1-2.0), hypertension (odds 1.4; 95% CI 1.1-1.8), and diabetes (odds 1.3; 95% CI 1.0-1.7). CONCLUSION: We found age, sex, hypertension, diabetes, and hypercholesterolemia to be independent risk factor for abnormal IMT in asymptomatic subjects over 40 years of age.