Explain Conventional Factors ?
Smoking, Hypertension, diabetes mellitus, obesity, hypercholesterolemia, and reduced physical activity are considered as conventional risk factors h CAD. In a prospective case-control study along patients with a first acute myocardial infarction (AMI) conducted in Bangalore, the adjusted odds ratios for smoking (either cigarettes or beads), Hypertension and fasting blood glucose (FBG) level >I40 mg/dl as 1.is1c factors for AM1 were 3.7, 3.0 and 2.8, respectively. Pais et al., from the same group confirmed these findings reiterating the importance of smoking as a risk factor in the Indian context and also showed an increasing risk of AM1 with increasing FBG even in the euglycemic range, irrespective of the presence of insulin resistance. Although this study did not show any differences in lipid levels between cases and controls, the high-density lipoprotein (HDL) levels were low and triglyceride (TG) levels were high in the population studied.
In the Chennai Urban Population Study 5 (CUPS-5), serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, TG and the total cholesterol to 1-IDL cholesterol ratio were linked to the presence of CAD in the Indians. The study also documented the predisposition of people with diabetes and impaired glucose tolerance (IGT) to develop CAD, and also showed significant association of systolic and diastolic blood pressure and body mass index (BMI) with the presence of CAD.
In a study by in North India, high prevalence of smoking, elevated serum total cholesterol levels, low I-IDL levels, Hypertension and diabetes was documented in both the urban and rural populations. Further the total cholesterol to I-IDL cholesterol ratio was found to be abnormal even in those subjects whose plasma cholesterol was in the normal range.
The role of leisure-time and work-related physical activity in determining risk of CAD in native Indian patients has not been studied in a structured way. However in a study of an urban community in Rajasthan, it was found that more than 70 per cent of the subjects were having a sedentary lifestyle. The adjusted odds ratios for a sedentary lifestyle as a risk factor for CAD were 1.7 in males and 4.5 in females. In a study on the prevalence of Cnrdio-vascular risk factors in India patients undergoing coronary artery bypass surgery, have shown high prevalence of most of the conventional Cardio-vascular risk factors especially diabetes, Hypertension, dyslipidaemia, smoking and obesity in the study population. About 96 per cent of the patients had at least one of the five major Cardio-vascular risk factors.
Dyslipidemia, family history of premature CAD and smoking were common in younger patients less than 45 years of age. In contrast, diabetes and Hypertension were more prevalent in the older individuals. Several other studies have also documented the association of conventional risk factors with CAD in the Indian population.
In summary, although conventional risk factors might not be sufficient to explain the increased prevalence of CAD among Indians, they are very important the context of disease prevalent and control because they can be easily identified and measured and because adequate steps including drugs are available to eliminate or control them.