Researchers at Oxford Population Health and King’s College London have found that people with high levels of some triglyceride-carrying apolipoproteins may still be two to three times more likely to develop coronary heart disease even if their LDL-cholesterol levels are under control. The results are published in Circulation Research.
People who are at risk of developing cardiovascular disease are often diagnosed by analysing the levels of apolipoproteins in their blood. Apolipoproteins are responsible for transporting lipids, such as cholesterol, in our blood and people who have higher levels of them have higher risks of developing cardiovascular disease. In order to reduce a person’s risk level, doctors routinely prescribe an LDL-cholesterol lowering drug known as a statin. Despite having optimal levels of LDL-cholesterol as a result of taking statins, some people may still have a ‘residual’ (or left over) risk of developing cardiovascular disease.
The researchers assessed the associations of 13 apolipoproteins with coronary heart disease, after adjustment for established risk factors and statin use, in blood samples provided to the PROCARDIS and Bruneck studies. The apolipoproteins were grouped into four main categories relating to the main types of lipid carried (Lp(a), LDL-C, HDL-C, and triglycerides).
- Triglyceride-carrying apolipoproteins (ApoC1, ApoC3 and ApoE) were associated with a two- to three-fold higher risk of coronary heart disease;
- ApoB, which is responsible for carrying LDL-cholesterol, was independently associated with a two-fold higher risk of coronary heart disease;
- Among HDL-cholesterol (sometimes called “good cholesterol”) related apolipoproteins, ApoA4 and ApoM were associated with a lower risk of coronary heart disease;
- The associations of the 13 apolipoproteins studied with coronary heart disease were consistent in both the PROCARDIS and Bruneck studies.
Robert Clarke, Professor of Epidemiology and Public Health Medicine at Oxford Population Health, and lead author of the study, said ‘There is an unmet clinical need to understand why some people still have a residual risk of developing coronary heart disease, despite lowering blood levels of LDL-cholesterol and consideration of other known risk factors. The associations identified in this study should prompt further research into apolipoproteins, particularly those that transport triglycerides in the body, which could help us to identify people at residual risk of developing coronary heart disease and inform personalised treatments to further reduce their risk levels beyond statin therapy.’