People with naturally lower levels of LDL cholesterol have a decreased risk of heart disease but a slightly increased risk of diabetes, according to research we funded.
Low density lipoprotein (LDL) is the harmful cholesterol, often referred to as "bad" cholesterol. Having too much LDL in your blood can cause fatty material to build up in your artery walls, which can eventually lead to heart attacks and strokes. Medicines that lower LDL cholesterol, such as statins, can help reduce a person's risk of a deadly or disabling heart attack or stroke.
Statins are widely prescribed in the UK, find out more about the medicines here.
What did the researchers learn?
Dr Michael Holmes, Senior Clinical Research Fellow from the University of Oxford, who led the research, said: "What we’ve shown in this study is that the role played by blood lipid levels in disease is a complex one."
The researchers found that people whose DNA contains versions of genes that naturally increase their levels of fat, such as LDL cholesterol or triglyceride, in their blood were at an increased risk of heart disease. They also found that individuals with genetic variations naturally increasing their LDL or HDL cholesterol, and possibly triglyceride levels, were at a slightly decreased risk of having type 2 diabetes.
The findings from this study therefore suggest that having lowered LDL cholesterol can cause a slight increase in a person's risk of developing diabetes. It has been known for some time that there is an increased risk of diabetes associated with statin treatment but this research indicates the risk is actually a consequence of having lowered LDL cholesterol, rather than a direct effect of the drug.
Why are these findings important?
The results of this study, published in the medical journal JAMA Cardiology, confirm findings from many previous studies which have shown that increased levels of LDL cholesterol increase a person’s likelihood of suffering from a heart attack or stroke. They also go some way to explaining why previous studies have shown that there is a modest increase in the risk of developing diabetes among people taking statins.
Further research is now needed to uncover exactly how an increase in LDL cholesterol in the blood protects against diabetes while increasing a person’s risk of suffering from heart disease. Dr Holmes added: "This study has provided yet more evidence that having increased HDL cholesterol may not be beneficial to heart disease. Of novel interest, our findings suggest that there could be a potential role for therapies that increase HDL cholesterol in the treatment and prevention of diabetes."
Should I still take my statin?
It is well known that the protective effect of statins on heart disease and stroke substantially outweighs the associated modest increase in risk of diabetes. The researchers confirm that clinical guidelines around statin usage should not change, but doctors should be vigilant in monitoring patients for risk of developing diabetes.
Commenting on the research, our Associate Medical Director, Professor Jeremy Pearson, said: "The results of this study have no implications for people taking statins. People taking a statin should continue to do so but consult their doctor if they have any concerns."
Need more information?
Find out more about statins in our Heart Matters magazine, where we asked an expert all the key questions on these life saving drugs.