Statins are famous, and their fame lies in their ability to bust cholesterol, the villain in many medical disorders such as heart attack (myocardial infarction) and stroke. Some may add that statins are infamous, and this is partly because of their side effects such as muscle pain. Love them or hate them, we can’t get away from statins…even as the debate rages about their benefits and downsides.
It is not surprising therefore that the statin debate will filter into neurology. The sticking point here however has nothing to do with cholesterol busting, but all to do with whether statins increase or reduce the risk of developing Parkinson’s disease (PD). Strange as it may seem, statins and PD have a long history. And a positive one generally, I hasten to add. There is a large body of evidence to suggest a protective effect of statins on PD as reflected in the following studies:
- Confounding of the association between statins and Parkinson disease: systematic review and meta-analysis
- Statin therapy prevents the onset of Parkinson disease in patients with diabetes
- Statin use and risk of Parkinson’s disease: A meta-analysis
- Statin use and its association with essential tremor and Parkinson’s disease
- Statin use and the risk of Parkinson’s disease: an updated meta-analysis
- Long-term statin use and the risk of Parkinson’s disease
- Discontinuation of statin therapy associated with Parkinson’s disease
It was therefore with some consternation that a recent study, published in the journal Movement Disorders, really put the cat among the pigeons. The paper is titled:
The authors of this paper set out to investigate ‘the controversy surrounding the role of statins in Parkinson’s disease’. In this retrospective analysis of over 2,000 people with PD, and a similar number of control subjects, the authors found that statins significantly increased the risk of developing PD. This is clearly a conclusion looking for a fight!
I must admit I was totally unaware there was any controversy about statins and PD. I was therefore curious to find out what studies are out there fuelling it. Which other trials have bucked the trend and reported an increased risk of PD from statins? And where best to find the answers but in PubMed, the repository of all human knowledge! And I found that there were only a few studies that did not report a protective effect of statins on PD, and these studies concluded, quite reasonably, that they found no relationship between PD and statins. Here are a few of the studies:
- Statin adherence and the risk of Parkinson’s disease: A population-based cohort study.
- Use of statins and the risk of Parkinson’s disease: a retrospective case-control study in the UK.
- Statin use and the risk of Parkinson disease: a nested case control study.
These papers reporting the absence of evidence seem happy to engage in an amicable debate to resolve the question.
One study however stood out like a sore thumb because it positively reported a negative effect of statins on PD (try and work that out!). This 2015 study, also published in Movement Disorders, is titled Statins, plasma cholesterol, and risk of Parkinson’s disease: a prospective study. The paper concludes that “statin use may be associated with a higher PD risk, whereas higher total cholesterol may be associated with lower risk“. Not only are the authors arguing that statins are bad for PD, they are also suggesting that cholesterol is good! This is a paper that was itching for fisticuffs.
What is a jobbing neurologist to do? What are the millions of people on statins to do? Whilst awaiting further studies, I will say stay put. Go with the bulk of the evidence! And keep track of The Simvastatin Trial, funded by The Cure Parkinson’s Trust. This trial is looking at the benefit of statins in slowing down PD. And surely, very soon, the science will lead to a resolution of the argument-all you need to do is keep track of everything PD in Neurochecklists.