Dyslipidemia and metabolic factors in the genesis of heart attack and stroke

Abstract

The relationship of dyslipidemia, particularly hypercholesterolemia to coronary heart disease is now well established. Although ischemic heart disease and stroke share many of the same risk factors, the relationship of cholesterol to stroke remains controversial. The 6-year and 12-year follow-up of the MRFIT study showed that elevated cholesterol significantly increased the risk for fatal nonhemorrhagic stroke. Atkins found no evidence that lowering plasma cholesterol influenced the incidence of fatal or nonfatal stroke and regression analysis showed no statistical association between the magnitude of cholesterol reduction and the risk for fatal stroke. We cannot preclude the possibility that more effective cholesterol lowering over a longer period of time might be effective. Hypertension is the most powerful risk factor for stroke. The San Antonio Heart Study reported a clustering of cardiovascular risk factors in individuals who developed hypertension during an eight-year follow-up period (higher levels of BP, fasting TC and LDLC, TG, glucose and insulin, and BMI, less favourable fat deposition, and lower HDL). Insulin resistance may be the unifying factor that results in those phenomena, the so-called syndrome X. The important factor underlying syndrome X may be central or visceral obesity, suggesting that maintenance or attainment of ideal weight would be a powerful preventive factor against both CHD and nonhemorrhagic stroke. There is evidence from the Treatment of Mild Hypertension Study that nutritional/hygienic measures can reduce the syndrome X risk factors and hence the risk of coronary heart disease and stroke.