Coronary Heart Disease in Indians

A report of WHO says that by the end of this century, India would account for more than half of the total heart patients in the world.

Incidence of  CAD in US is 1 %, whereas it was as high as 3 % among Indians and about 7 % among north Indians.

Higher Rate –   2-4 fold higher prevalence of CAD and mortality. Higher rates of clinical events – double than the Whites, 4 fold higher than Chinese.

Greater pre maturity – 5-10 yrs. earlier onset of first myocardial infarction. 5–10 fold higher risk of myocardial infarction and death in the younger age < 40 yrs.

Greater severity – Three vessel disease common even in younger pre menopausal women. Large infarction and greater muscle damage in younger age. 

Lower prevalence of conventional risk factors like hypertension, obesity, cigarette smoking. Cholesterol levels similar to Whites but higher than other Asians.

Higher prevalence of thrombogenic risk factors like – high levels of lipoprotein (a), homocysteine, ApoB, high levels of Triglycerides, fibrinogen, plasminogen activator inhibitor – 1, low levels of HDL.   

The increased incidence of the CAD in the Indians is due to a combination of Nature (genetic predisposition) and Nurture (environmental factors). Because of the genetic predisposition the harmful effects of environmental factors are greatly magnified. Adverse life style factors include those associated with affluence, urbanization and mechanization. When people move from the rural to the urban environment they tend to become sedentary.

Decreased physical activity and increases consumption of calories and saturated fatty acids, insulin resistance and athrogenic dyslipidaemia all add and have synergistic effect on the development of CAD.

Because Indians have higher prevalence of thrombotic risk factors the conventional risk factors become doubly dangerous. 

Lipoprotein(a) elevated levels render many Indians genetically susceptible to CAD as early as childhood. It has been seen that Lp(a) level > 30 mg % is associated with increases

High rate of CAD in Indians are in sharp contrast to  very low rates in other Asians. Despite high rates of smoking and hypertension, CAD rates among both Chinese and Japanese are about 4 fold lower than in US.

The low rate of CAD in Chinese despite high rates of other risk factors is attributed to their highly Anti-Atherogenic Lipid Profile. 

In a study the typical levels in rural China were:

•  Cholesterol: 127 mg /dl
• LDL: 63 mg /dl
• Triglycerides: 100 mg /dl
• HDL: 44 mg /dl
• TC/HDL ratio : 2.9

Others have reported cholesterol levels as low as 80 mg /dl in some Chinese communities, where CAD is virtually non existent.

Following are some observations of a Berkeley study: –