Good health

Cholesterol that’s too low could increase risk of some strokes: Study

Jul 03, 2019

New research shows the risk of hemorrhagic stroke increases dramatically when LDL levels are too low. Source: Getty

Keeping cholesterol levels in check is essential in helping to reduce the risk of heart attacks, strokes and cardiovascular disease – but a new study has claimed finding the right balance is critical.

High levels of low-density lipoprotein (LDL), or ‘bad’ cholesterol levels, can be caused by both genetic and lifestyle factors and, depending on the situation, it’s not uncommon for health professionals to suggest lifestyle changes or medication to reduce these levels.

But new research from Penn State University now claims that cholesterol that is too low may actually increase the risk of hemorrhagic stroke – where a brain aneurysm bursts or a weakened blood vessel leaks. Over nine years, researchers examined the relationship between LDL and hemorrhagic stroke and discovered that LDL cholesterol levels below 70 mg/dL carried a higher risk.

Researchers hope the results, published in the Neurology Journal, could help refine and personalise recommendations for cholesterol levels, while the study claimed that balance is key when deciding the optimal target level.

“You can’t go to either extreme — too high or too low,” Xiang Gao, director of the Nutritional Epidemiology Lab at Penn State, said in a statement. “And if you’re at a high risk for hemorrhagic stroke due to family history or risk factors like high blood pressure and heavy alcohol drinking, you may want to be extra careful about LDL cholesterol levels.”

While current guidelines recommend lowering LDL cholesterol as a way of reducing the risk of a heart attack or ischemic stroke, there’s concern about a link between low LDL levels and hemorrhagic stroke. Ischemic strokes differ because they’re caused by a blood vessel in the brain becoming blocked by a clot.

The latest study analysed 96,043 people with no history of stroke, heart attack or cancer at the beginning of the study. LDL cholesterol levels were measured annually for nine years following the start of the study and reported incidents of hemorrhagic stroke were confirmed by medical records.

It was found that participants who had LDL cholesterol levels between 70 and 99 mg/dL had a similar risk of hemorrhagic stroke, but this risk increased significantly when levels dipped below 70 mg/dL. The risk increased by 169 per cent for participants with LDL levels less than 50mg/dL when compared with LDL levels between 70 and 99 mg/dL.

“Traditionally, an LDL cholesterol level of more than 100 mg/dL had been considered as optimal for the general population and lower in individuals at elevated risk of heart disease,” Gao said. “We observed that the risk of hemorrhagic stroke increased in individuals with LDL cholesterol levels below 70 mg/dL. This observation, if confirmed, has important implications for treatment targets.”

While the results are based on a large community-based study, more research needs to be conducted to confirm the findings. It’s always important to talk to a health professional about cholesterol and the best ways to manage it.