Researchers at Penn State College of Medicine and National Institute of Environmental Health
Sciences found that use of statins might not be associated to lower the risk
for Parkinson's disease. The research findings cast doubts on reports
suggesting that cholesterol-lowering medications might protect against
According to the National Parkinson
Foundation, Parkinson's disease affects about one million Americans and an
estimated four to six million people worldwide. Although the cause of PD is
unknown, damage to dopamine-producing neurons eventually leads to the movement
disorders that are a hallmark of the disease.
professor of neurology and vice chair for research, Penn State College of
Medicine, previously reported an association between high blood cholesterol
levels and lower incidence of PD. A low incidence of heart attack and stroke in
PD patients in movement disorder clinics, despite their usually advanced age
motivated these studies. Other studies also reported similar findings.
However, evidence has been somewhat inconsistent. The use
of statins has also been associated with a lower incidence of PD in several
recent epidemiology studies, leading some researchers to hypothesize that these
medications, which lower levels of LDL -- bad cholesterol -- may protect
against PD. Those studies, however, failed to account for cholesterol levels
prior to the widespread use of statins in the U.S. population, Huang said,
noting that as strength of the new study.
looked at blood cholesterol levels, medications and PD status in participants
in the ongoing, long-term Atherosclerosis Risk in Communities study.
Cholesterol readings were taken at three-year intervals over the course of a
decade from 1987 to 1989, before widespread statin use began.
"We confirmed our previous finding that high total
cholesterol and LDL cholesterol were associated with a lower risk of PD,"
Huang said. "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.
Although the analysis on statin use and PD was based on a fairly small number
of PD cases, this preliminary data argues against the hypothesis that statins
protect against PD."
The researchers reported their
finding in the journal Movement Disorders
"One possibility," Huang said, "is that
statin use can be a marker of people who have high cholesterol which itself may
be associated with lower PD risk. This could explain why some studies have
found an association between use of these medications and low incidence of PD.
Most importantly, this purported benefit may not be seen over time."
Future research should focus on if and why cholesterol may
protect against PD. Although blood cholesterol is not indicative of cholesterol
in the brain, there is increasing evidence that PD may begin outside the brain.
Statin-induced decreases in blood cholesterol levels may have unknown
consequences in these peripheral areas. A compound called coenzyme Q10 that is
produced alongside cholesterol may also be an area of future PD research.
Statins reduce coenzyme Q10, which helps produce energy for cells and is
hypothesized to have protective qualities in nerve cells.
"Statins have been proven to be effective in the
primary and secondary prevention of cardiovascular events and stroke. Although
some have proposed that statins might be a 'cure-all' drug," Huang said,
"this might be a case where what's good for the heart isn't good for the
An estimated 43 million Americans currently
take statins or are eligible for statin therapy. Recent updates to American
Heart Association guidelines are expected to increase that number to 56 million
or more. The new guidelines recommend statin use for some patients without high
cholesterol but who have other risk factors for heart disease and stroke.
"Statins have been very important for preventing and
treating vascular disease, but we need more research to understand if in some
cases there is collateral damage," Huang said. Until more epidemiological
and basic research can be conducted to further parse out the associations
between PD, cholesterol and statins, physicians and scientists should be
cautious in promoting health benefits of statins for PD without a good
understanding of clinical evidence and potential biological mechanisms, Huang
Patients and physicians considering statins for
cardiovascular health and stroke prevention should consider their individual
cases. "This is evidence that personalized medicine is better than a
one-size-fits-all approach," Huang said.