Effect of drugs on high-density lipoprotein

30-year trends in serum lipids among United States adults: results from the National Health and Nutrition Examination Surveys II, III, and 1999-2006

Data from National Health and Nutrition Examination Survey (NHANES) II (1976 to 1980), NHANES III (1988 to 1994), and NHANES 1999 to 2006 were examined to assess trends in total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein cholesterol, triglycerides (TGs), lipid-lowering medication use, and obesity. Age-adjusted decreases in TC (210 to 200 mg/dl) and LDL cholesterol (134 to 119 mg/dl) were observed. Those with high TC showed a decrease of 9% from NHANES II to NHANES 1999 to 2006, whereas those with LDL cholesterol ≥160 mg/dl showed a decrease of 8%. A significant increase in mean high-density lipoprotein cholesterol was observed (50 to 53 mg/dl, p <0.001), most likely due to changes in methods. Those with TG levels ≥150 mg/dl showed a decrease from NHANES II to NHANES III from 30% to 27% but then an increase from NHANES III to NHANES 1999 to 2006 from 27% to 33%. Since NHANES III, mean TG levels have increased 12% from 130 to 146 mg/dl. In the 2 most recent surveys, self-reported "high cholesterol" increased from 17% to 27%, and self-reported lipid medication use by those with high cholesterol increased from 16% to 38%. Mean body mass index increased from 26 to 29 kg/m(2), and prevalence of obesity doubled and was significantly associated with increased TG. In conclusion, recent favorable trends in TC and LDL cholesterol are likely due to increased awareness of high cholesterol and the greater use of lipid-lowering drugs. However, countertrends in obesity and TG levels, if continued, will likely have a negative impact on cardiovascular disease in the future.

High-density lipoprotein and transport of cholesterol and triglyceride in blood

High-density lipoproteins (HDL) contain approximately 25% of the cholesterol and <5% of the triglyceride in the plasma of human blood. However, the dynamic exchange of lipids and lipid-binding proteins is not revealed by simply considering the mass of material at any point in time. HDL are the most complex of lipoprotein species with multiple protein constituents, which facilitate cholesterol secretion from cells, cholesterol esterification in plasma, and transfer of cholesterol to other lipoproteins and to the liver for excretion. They also play a major role in triglyceride transport by providing for activation of lipoprotein lipase, exchange of triglyceride among the lipoproteins, and removal of triglyceride rich remnants of chylomicrons and very-low-density lipoproteins after lipase action. In addition, antioxidative enzymes and phospholipid transfer proteins are important components of HDL. Many of the proteins of HDL are exchangeable with other lipoproteins, including chylomicrons and very-low-density lipoproteins. The constantly changing content of lipids and apolipoproteins in HDL particles generate a series of structures that can be analyzed by using separation techniques that depend on size or charge of the particles. Interaction of these various structures can be very different with cell surfaces depending on the size or apolipoprotein content. A series of different transport proteins preferentially exchange lipids with specific structures among the HDL but interact poorly or not at all with others. The role of these differing forms of HDL and their interactions with cells and other lipoprotein species in plasma is the subject of intense study stimulated by the potential for reducing atherogenesis. The strength of this is only partially indicated by the correlation of higher total levels of the HDL particles with reduced incidence of vascular disease in various clinical trials and epidemiological studies.