Parkinson’s disease is the second most common neurologic disorder in Australia after dementia. There are around 80,000 people affected by this condition with just over 30 diagnosed on a daily basis. It is not just a condition of old people and, in fact, 20% of people with the disease are diagnosed under the age of 50. The disease is characterised by tremors, problems with movement, impaired balance and coordination along with muscle rigidity.
A few years back, a study from Taiwan suggested that people taking statin drugs had lower rates of Parkinson’s disease. A new study published in the Journal Movement Disorders, examined the medical insurance claim data from 50 million people. 22,000 people in the database suffered Parkinson’s disease of which just over 2300 were newly diagnosed. The researchers then took a control group of people with similar demographics and compared statin use in both groups. There was a significantly higher risk for developing Parkinson’s disease in those prescribed statins, especially at the commencement of statin therapy.
Interestingly, the risk was much higher for fat soluble statins such as atorvastatin and simvastatin as opposed to the water-soluble statins rosuvastatin and pravastatin. Fat soluble statins can easily cross the fatty, blood-brain barrier and penetrate into the nerves.
There are a few issues here:
- Is it a direct toxic effect of the statins on nerves that increases the risk for Parkinson’s disease?
- There is some work to suggest that high cholesterol levels protect against Parkinson’s disease and could it be that reducing cholesterol levels damages nerves and therefore increases Parkinson’s disease risk?
- There have been significant concerns for a number of years about the link between memory loss, statin therapy and in particular, fat soluble statins, so, does this have any implications for the management of Alzheimer’s disease?
Coronary artery and cerebrovascular disease caused by atherosclerosis are very common and in my opinion, statin therapy should be a part of the management of these conditions. Thus, many people suffering some degree of atherosclerosis may also develop the relatively common Parkinson’s disease. As I have stated on numerous occasions, the only people in my opinion who should be receiving statin therapy are those with established vascular disease such as a prior stent, heart attack or bypass or a coronary equivalent such as an atherosclerotic stroke. The only other group who should be receiving statin therapy are those people who have a high coronary calcium score as demonstrated by a CT scan that takes a snapshot of the coronary arteries (without an injection — the intravenous CT coronary angiogram is unnecessary as a screening test for heart disease).
But, if a person is displaying early signs of Parkinson’s disease, should the statin be ceased even if they do have one of the above conditions?
Unfortunately, this study raises more questions than it gives answers, but does bring in more caution for all doctors when prescribing statins purely because of an elevated cholesterol level. How many times does this topic have to be raised before conservative doctors start to examine their own practices?