Obesity and Dyslipidemia.

Abstract

Abnormalities in lipid metabolism are very commonly observed in patients who are obese. Approximately 60-70% of patients with obesity are dyslipidemic. The lipid abnormalities in patients who are obese include elevated serum TG, VLDL, apolipoprotein B, and non-HDL-C levels. The increase in serum TG is due to increased hepatic production of VLDL particles and a decrease in the clearance of TG rich lipoproteins. HDL-C levels are typically low and are associated with the increase in serum TG. LDL-C levels are frequently in the normal range or only slightly elevated but there is an increase in small dense LDL. Patients who are obese are at an increased risk of developing cardiovascular disease and therefore treatment of their dyslipidemia is often indicated. Life style induced weight loss will decrease serum TG and LDL-C levels and increase HDL-C levels. In most patients the changes in lipid levels with life style induced weight loss are not very robust and are proportional to the change in weight. Dietary constituents of a weight loss diet have a small but significant impact on the changes in lipid levels. Low carbohydrate diets decrease TG levels to a greater extent than high carbohydrate diets. High fat diets blunt the decrease in LDL-C that occurs with weight loss. The increase in HDL-C with weight loss is greatest with a high fat diet but the significance of this increase on cardiovascular disease risk is uncertain. Weight loss medications will also improve dyslipidemia. Bariatric surgery results in robust weight loss and has a marked effect on serum lipid levels. Remission of hyperlipidemia with gastric bypass surgery is frequently observed. The reduction in cardiovascular disease with statin therapy is no different in patients with a BMI >30 or BMI <25 (i.e., statins are effective in patients who are obese). Many, if not most, patients who are obese should be on statin therapy and some will require the addition of other LDL-C decreasing drugs to achieve satisfactory reductions in LDL-C. The mixed dyslipidemia that is frequently observed in patients who are obese will often require combination therapy. However, recent studies have failed to demonstrate that adding fibrates or niacin to statin therapy provides additional benefits beyond statins alone. However, the addition of the omega-3-fatty acid, icosapent ethyl, to statin therapy has been shown to decrease cardiovascular events. For complete coverage of all related areas of Endocrinology, please visit our on-line FREE web-text, WWW.ENDOTEXT.ORG.