If cholesterol-lowering statins were able to prevent Parkinson’s disease, we’d have a powerful new way to prevent or delay the neurodegenerative disease. However, the research on its effectiveness in doing that is shaky; a new study shakes things up even more, finding that statins may not only be unable to lower Parkinson’s risk but possibly even worsen it.

Parkinson’s, which affects an estimated one million people and is newly diagnosed in up to 60,000 people each year, is caused by the malfunction and death of the brain’s dopamine cells. These cells are vital to movement and coordination. As a result of this destruction, the body ends up experiencing symptoms like tremors in the hands, arms, legs, and face; bradykinesia, or slower body movement; stiff limbs, and postural instability.

Previous research has suggested statins’ could cross the blood-brain barrier and, with their anti-inflammatory properties, provide neuroprotective benefits to the dopaminergic pathways. However, according to the new research, these neuroprotective benefits may actually come from having high cholesterol, particularly LDL (low-density lipoprotein, or “bad” cholesterol) rather than from taking the statins to treat it.

“We confirmed our previous finding that high total cholesterol and LDL cholesterol were associated with a lower risk of PD (Parkinson’s disease),” said Xuemei Huang, an author of the study and professor of neurology at Penn State College of Medicine, in a press release. “Moreover, statin use over the course of the study did not protect against PD, and in fact appeared to increase PD risk in the long term.”

Huang admitted the study’s sample size was small, only involving 56 cases of Parkinson’s. But the preliminary data behind the findings, Huang says, is strong. For one, some research suggests Parkinson’s may begin outside the brain; as cholesterol is produced, so is a compound called coenzyme Q10, which energizes cells and has shown hints of being able to protect nerve cells. As statins reduce cholesterol, they may also reduce levels of Q10, making the body vulnerable to developing Parkinson’s.

Moreover, Huang noted that most of the studies linking statins to lower Parkinson’s risk failed to account for cholesterol levels prior to widespread statin use in the U.S. So, Huang’s team looked at blood cholesterol levels, medications used, and Parkinson’s diagnoses in a group of people who participated in the Atherosclerosis Risk in Communities study between 1987 and 1998 — before statins were widely used.

“Statins have been proven to be effective in the primary and secondary prevention of cardiovascular events and stroke,” Huang said. “Although some have proposed that statins might be a ‘cure-all’ drug, this might be a case where what’s good for the heart isn’t good for the brain.” More research will eventually determine whether statins are beneficial or not for Parkinson’s, but until then, Huang urged caution among physicians promoting the benefits of statins for Parkinson’s. “This is evidence that personalized medicine is better than a one-size-fits-all approach.”

Source: Huang X, Alvaro A, Guo X, et al. Statins, plasma cholesterol, and risk of Parkinson's disease: A prospective study. Movement Disorders. 2015.