Jan 10 (HeartCenterOnline) - A unique population study has found that non-HDL cholesterol can predict heart disease in individuals with type 2 diabetes. The results are published in the January 2003 issue of Diabetes Care.

Non-HDL cholesterol is defined as the total cholesterol level minus the level of high density lipoproteins (HDLs, the so- called "good" cholesterol). Non-HDL cholesterol refers, then, to those types of lipoproteins contributing to the process of atherosclerosis.

Lipoproteins are proteins that wrap around both cholesterol and other fatty materials and transport them through the bloodstream. HDLs move easily through the blood and are actually beneficial to the body. They are stable and do not stick to artery walls. They help to prevent heart disease by carrying cholesterol away from the arteries and back to the liver, where the process of their removal from the body begins. "Bad" cholesterol, LDLs, contain more fat and less protein than HDLs. LDLs are unstable; they tend to fall apart. Rather than being removed from the body by the liver, they stick to artery walls and contribute to plaque build-up. This can eventually lead to hardened arteries (atherosclerosis) or coronary artery disease. Therefore, high levels of LDLs are strongly associated with increased risk for heart disease.

Smaller amounts of cholesterol may travel in very low- density lipoproteins or another type of lipoprotein called chylomicrons (which are rich in triglycerides). Many people with high levels of "bad" cholesterol also have high triglyceride levels because both types of fats have similar risk factors (e.g., obesity and diabetes).

Earlier studies have shown that total non-HDL cholesterol provided an advantage over LDLs alone in predicting coronary artery disease (CAD). Moreover, the National Cholesterol Education Program recommended non-HDL measurements to predict CAD risk in diabetes. The current study's researchers, however, noted that no studies of populations had been done to confirm this recommendation. Named The Strong Heart Study, the researchers investigated the predictive value of non-HDLs by studying individuals among 13 American Indian communities. The participants consisted of 4,549 men and women 45 to 74 years of age; 2,108 had diabetes. None had heart disease at the beginning of the study, which was conducted from 1989 to 1998.

There is a high prevalence of diabetes in American Indians, who have - in fact - a higher rate of diabetes than any other ethnic group in the United States. Since diabetes is a risk factor for heart disease, the researchers felt that this population warranted study. Data from the participants were compiled from physical examinations, lab tests and personal interviews.

Results showed that heart disease developed in 521 of the 2,108 diabetic individuals, and in 145 of the 2,060 non- diabetics. The effect of non-HDL cholesterol on heart disease risk was deemed "continuous," "significant" and a "strong predictor." The researchers recognize, however, that the results reflect a discrete population. Since lifestyle and ethnicity can impact on risk factors for heart disease, the researchers encourage further non-HDL studies in other populations.

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