Relationship of lipoprotein(a) with intimal medial thickness of the carotid artery in type 2 diabetic patients in south India

Abstract

Objective: The objective of this study was to investigate the association of lipoprotein(a) [Lp(a)] levels with intimal medial thickness (IMT) in Type 2 diabetic patients in south India. Study design: We studied 587 consecutive Type 2 diabetic patients at the M.V. Diabetes Specialities Centre, Chennai. The mean age of the study group was 55 ± 10 years and 71.2% were males. IMT of the right common carotid artery was determined using high-resolution B mode ultrasonography. Lp(a) levels were measured using ELISA. Since the frequency distribution of Lp(a) was skewed, Lp(a) values were log transformed and the geometric mean was used for statistical analysis. The tertiles of IMT were determined to analyse the association of Lp(a) and other factors with IMT. Result: The mean Lp(a) level in the study patients was 18.9 ± 3.1 mg/dl (geometric mean ± sd) and the mean IMT of the study subjects was 0.93 ± 0.19 mm (mean ± sd). The prevalence of carotid atherosclerosis (defined as IMT > 1.1 mm) among subjects with elevated Lp(a) levels > 20 mg/dl was significantly higher compared with those with Lp(a) levels = 20 mg/dl (26.9% vs. 16.3%, P = 0.003). Lp(a) levels increased with increase in tertiles of IMT (anova, P < 0.05). Pearson correlation analysis of carotid IMT with other cardiovascular risk factors revealed strong correlation of IMT with age (P < 0.0001), duration of diabetes (P < 0.0001), systolic blood pressure (P < 0.0001), diastolic blood pressure (P = 0.006), LDL-cholesterol (P = 0.023), HbA_1c (P = 0.017) and Lp(a) (P < 0.0001). Multiple logistic regression analysis showed age (P = 0.010), LDL-cholesterol (P = 0.032) and Lp(a) (P = 0.021) to be associated with carotid atherosclerosis. Conclusion: The results suggest that Lp(a) has a strong association with IMT of carotid arteries in Type 2 diabetic subjects in south India.