Statins May Cut Parkinson’s Risk
Statin users may get an added benefit from the cardioprotective lipid-lowering – a modestly reduced risk of developing Parkinson’s disease, researchers found.
Men and women in two large prospective cohorts were 26% less likely to develop Parkinson’s disease if they were taking a statin than if they weren’t currently on one (adjusted pooled P=0.049), Xiang Gao, MD, PhD, of Harvard and Brigham and Women’s Hospital in Boston, and colleagues reported in the March issue of the Archives of Neurology.
The benefit appeared limited to statin users under age 60 at baseline, who saw a bigger impact of the drug with an adjusted pooled relative risk of 0.31 (P=0.02 for effect, P=0.03 for interaction with age).
Preclinical studies have pointed to several mechanisms of statins, such as a reducing oxidative stress, that would be expected to alleviate neuroinflammation and thus Parkinson’s disease risk, Gao’s group explained.
However, “the overall epidemiological evidence relating statin use to Parkinson’s disease risk remains unconvincing,” the group cautioned, so the marginally significant overall result in their analysis might have been due to chance.
But at least there didn’t appear to be a negative impact, a possibility, they noted, because statins lower plasma coenzyme Q10 levels, which may be neuroprotective in Parkinson’s disease.
– Note that in this prospective study, the risk of Parkinson’s disease was marginally significantly lower among current statin users compared with nonusers.
– Point out that the association was observed principally in participants younger than 60 years of age.
Statins aren’t entirely benign, as the FDA has repeatedly highlighted in recent months through warnings added to the label regarding the risk of diabetes and transient memory problems with drugs across the class and a caution about drug-drug interactions with HIV/AIDS and hepatitis C medications.
“Given the potential adverse effects of statins, further prospective observational studies are needed to explore the potential effects of different subtypes of statins on risk of Parkinson’s disease and other neurodegenerative diseases,” Gao and colleagues concluded.
For their study, the researchers pooled the data on 38,192 men participating in the Health Professionals Follow-up Study and 90,874 women in the Nurses’ Health Study.
So what are those risk factors?
If you are 60 or over you are more likely to get PD. Seventy-five percent of all cases of PD begin after age 60 and incidence increases every decade after that up to about 80 years of age. If you do not have PD by age 80 your chances of getting it are small and are substantially lower than when they were when you were 70 or 60. Most people develop initial symptoms of PD in middle age. The idea is that dopamine production declines with age and you start to feel that decline in middle age. When the decline is steep and profound you get PD.
Men are slightly more at risk than women to get PD. Nobody knows why men are more vulnerable to PD than women. It may be that the female hormone estrogen protects dopamine neurons to some extent.
If someone in your family – a close blood relative for example – has or had PD, then your chances of getting PD are slightly increased. Familial forms of PD suggest that certain genetic problems may contribute to the causes of PD. An abnormality in one such gene, Parkin, may be a predictor of the onset of Parkinson’s at a young age (before age 50). Alpha Synuclein is another gene implicated in PD. When damaged it contributes to abnormal clumping of dopamine cells (called Lewy bodies).
EXPOSURE TO TOXINS
Excessive exposure to industrial toxic chemicals such as pesticides and herbicides can increase the risk of developing PD. People who live in a rural agricultural area and used well water for drinking and cooking were found to have higher rates of PD, possibly because they were exposed to toxic chemicals in the form of pesticides.
Among them, 3,306 of the men and 7,729 of the women reported taking a cholesterol-lowering drug at least twice a week on questionnaires at the analysis baseline in 1994.
The lower incidence of Parkinson’s disease among them during 12 years of follow-up was evident despite adjustment for age, smoking, caffeine and lactose consumption, ibuprofen use, history of major chronic disease, and other factors.
Only about 70% of the lipid-lowering drug use at baseline was likely to have actually been statins, the researchers cautioned.
But calculating backward which patients were taking statins at that point from the 2000 questionnaire that asked specifically about duration of use, statins were associated with a 24% reduced risk of Parkinson’s disease incidence similar to that in the overall analysis, although missing statistical significance.
That updated statin use predicted reduced risk of Parkinson’s six or more years after starting on the cholesterol-reducing medication (pooled relative risk 0.70, P=0.02) but with shorter-term use.
Vitamin D May Lower Risk of Parkinson’s Disease
Higher levels of vitamin D appear to reduce the risk of an individual developing Parkinson’s disease, a new report suggests.
Vitamin D is well known to play a role in bone health with emerging evidence suggesting a beneficial effect for lowering the risk of cancer, heart disease and type 2 diabetes.
“Recently, chronically inadequate vitamin D intake was proposed to play a significant role in the pathogenesis of Parkinson’s disease,” the authors write.
“According to the suggested biological mechanism, Parkinson’s disease may be caused by a continuously inadequate vitamin D status leading to a chronic loss of dopaminergic neurons in the brain.”
Individuals with higher levels of vitamin D appear to have a reduced risk of developing Parkinson’s disease, according to a report in the July issue of Archives of Neurology, one of the JAMA/Archives journals.
Paul Knekt, D.P.H., and colleagues at the National Institute for Health and Welfare, Helsinki, Finland, studied 3,173 Finnish men and women age 50 to 79 who did not have Parkinson’s disease at the beginning of the study, in 1978 to 1980.
The finding fits with the long preclinical stage assumed for Parkinson’s, the researchers noted.
Additional cautions on limitations of the study included the possibility of residual confounding and even indication bias, because some prior prospective studies have linked elevated cholesterol to lower Parkinson’s disease risk.
Also, “because we used cholesterol-lowering drug use as a surrogate of statin use in our study, we cannot exclude the possibility that the significant statin age interaction is confounded by the indications that younger participants were more likely to receive the newer and more expensive cholesterol-lowering drugs such as statins relative to older participants,” they added.
Differences between statins in impact on Parkinson’s disease are also possible, Gao’s group noted.
The study was supported by grants from the National Institute of Neurological Disorders and Stroke.
Gao reported having been a consultant for Teva.
Primary source: Archives of Neurology
Source reference: Gao X, et al “Prospective study of statin use and risk of Parkinson Disease” Arch Neurol 2012; 69: 380-384.