ABSTRACT
BACKGROUND: Socioeconomic differences have been shown to be linked with the prevalence of coronary artery disease (CAD) and its risk factors such as dyslipidaemia based on urban-rural comparisons. However, very little data are available on the prevalence of dyslipidaemia within an urban environment. The aim of this study was to assess the pattern of dyslipidaemia in two different socioeconomic groups within an urban South Indian population. METHODS: The Chennai Urban Population Study is an epidemiological study involving two residential areas in Chennai, South India representing different socioeconomic strata. Of the 1399 eligible subjects (age > or = 20 years), 1262 (90.2%) participated in the study (Tirumangalam: middle income group, 479 subjects, response rate 91.4%; and T. Nagar: low income group, 783 subjects, response rate 89.4%). A detailed questionnaire on the socioeconomic and clinical background of the subjects was collected. Biochemical investigations included lipid profile and oral glucose tolerance tests. The classification of lipid abnormalities was done according to the National Cholesterol Education Programme-Adult Treatment Panel III [NCEP (ATP III)] guidelines. RESULTS: The Tirumangalam group (mean monthly income of Rs 8075) represents the middle income group, while the T. Nagar group (mean monthly income of Rs 1399) represents the low income group. The prevalence rates of lipid abnormalities were higher among the middle income group compared to the low income group. The prevalence of high risk cholesterol levels in men was 10.6% (middle income group) v. 2.7% (low income group; p<0.001) and among women 19.1 v. 4.7% (p<0.001). Similarly, the prevalence of high risk triglyceride levels in men was 15.7% v. 9.3% (p=0.02) and among women 10.3% v. 7.5% (p<0.05); high risk low density lipoprotein (LDL) levels among men was 7.8% v. 3.0% (p=0.01), and among women 11.2% v. 4.5% (p<0.001). High density lipoprotein (HDL) cholesterol levels were lower in the low income group but the total cholesterol/HDL cholesterol ratio was higher among men in the middle income group (p<0.001) but not among women. Logistic regression analysis revealed that socioeconomic status had a strong association with hypercholesterolaemia and high LDL levels, even after adjusting for age and body mass index. CONCLUSION: Socioeconomic factors influence the pattern of dyslipidaemia in this urban South Indian population, with dyslipidaemia being more common and severe in the middle income group.