Endometrial cancer risk in relation to serum lipids and lipoprotein levels.

Blood lipids are useful biochemical indicators for assessing the risk of a number of chronic diseases, particularly those associated with obesity. In a multicenter case-control study that included 256 cases and 185 controls less than 75 years old, we studied the risk of endometrial cancer in relation to serum cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and triglycerides. Contrary to expectation, blood lipids were, in general, lower among cases compared with controls. The effects of low blood lipids, specifically cholesterol and low density lipoprotein cholesterol, were limited to older women (> or = 55 years). Risk of the disease in this subgroup of 177 cases and 110 controls was increased 3-4-fold among those with the lowest cholesterol or low density lipoprotein cholesterol values. For example, after adjustment for age, education, smoking status, obesity, and body fat distribution, the relative risks of endometrial cancer across decreasing quartiles of serum cholesterol were 1.0, 2.5, 2.4, and 4.2 (P for trend < 0.01). We examined blood lipid levels by disease stage. The low lipid values of older cases did not appear to be a consequence of the disease. While we cannot rule out the possibility that hypocholesterolemia is a predisposing factor for endometrial cancer, there is no obvious biological explanation for the inverse association.