Carotid Intima-media Thickness and Risk of Cardiovascular Disease among Healthy Adult Volunteers in North Eastern Nigeria

Background: Assessment of carotid intima media thickness (CIMT) have evolved over the years to assume a key role in assessment of cardiovascular risk. However, there is paucity of data on CIMT among Nigerian. We assessed CIMT and its association with cardiovascular risk factors among apparently healthy individuals.

Methods: Apparently healthy adults were consecutively recruited from July 2013 through March 2014 at the Federal Medical Centre Nguru. Anthropometric variables were measured and blood samples collected. CIMT was determined at the common carotid, carotid bifurcation, and proximal internal carotid artery levels using a high-resolution 2-D USS scanner, and values above 0.9mm considered abnormal. Means of continuous variables were compared using Student t-test or Mann-Whitney U test, while between groups mean was compared using one-way ANOVA. Association of CIMT other continuous variable was assessed using bivariate correlation and multivariable linear regression models. A p value of <0.05 was considered significant for all statistical analysis.

Results: Ninety nine apparently healthy consenting adults comprising 63(63.6%) males and 36(36.4%) females were consecutively recruited. Their median (interquartile range) age was 34(27) years. Mean left CIMT at common carotid, carotid bifurcation and internal carotid artery levels were 0.82(0.22), 0.91(0.23) and 0.85(0.21) respectively (F=3.57, p=0.029). There was no difference in CIMT between the left and the right sides. Thirty one (31.3%) had CIMT above 0.9mm. Significant correlation was found between CIMT and age (r2=0.33, p<0.001), body mass index (BMI) (r2=0.06, p<0.001), systolic blood pressure (r2=0.11, p=0.001), glycated haemoglobin (r2=0.34, p<0.001), total cholesterol (r2=0.42, p<0.001), LDL-c (r2=0.47, p<0.001) and HDL-c (r2=-0.14, p<0.001). Age, BMI, blood pressures, total cholesterol, LDL-c and HDL-c independently predicted CIMT.

Conclusion: The prevalence of increased CIMT is high among healthy adults, and CIMT correlated positively with other cardiovascular risk factors. Routine assessment of CIMT may identify individuals with increased risk for cardiovascular diseases and result in more targeted preventive measures.