It's not the first time that the cholesterol-lowering drugs known as statins have been linked to Alzheimer's disease. A small clinical trial in 2005 suggested that Lipitor might improve mental function in people with early Alzheimer's disease.
Both Lipitor and Zocor are in clinical trials to see whether they really do help people with Alzheimer's disease. But now there's compelling evidence that Zocor may actually prevent not only Alzheimer's disease, but Parkinson's disease, too.
The provocative new data come from Boston University researcher Benjamin Wolozin, MD, and colleagues.
"Many people are looking at whether statins might prevent the progression of dementia in people with Alzheimer's disease," Wolozin tells WebMD. "But a lot of people in the field think that if you start statin treatment at the time you already have the disease, it might be the wrong time. It might be nice to talk about how to prevent the disease."
To see whether taking statins had any effect on Alzheimer's disease, Wolozin's team used the immense U.S. Veterans Affairs database, with detailed information on 4.5 million patients. Some 727,000 of these patients took Zocor, about 54,000 took Lipitor, and about 54,000 took Mevacor.
In patients over age 64, those who took Zocor were 54% less likely to get Alzheimer's disease and 49% less likely to get Parkinson's disease than were matched patients not taking statin drugs.
Those who took Lipitor were 9% less likely to get Alzheimer's disease, a finding that was not statistically significant. Lipitor did not affect Parkinson's disease risk.
Mevacor had no effect on risk of either Alzheimer's disease or Parkinson's disease.
D. Larry Sparks, PhD, director of the Roberts Laboratory for Neurodegenerative Disease Research at the Sun Health Research Institute in Sun City, Ariz., is involved in clinical trials of statins for Alzheimer's disease but was not involved in the Wolozin study.
"This study keeps alive the idea that statins may be of benefit in the treatment of Alzheimer's disease and maybe even in mild cognitive impairment," Sparks tells WebMD. "But the most important part is that this addresses the role of cholesterol-lowering medications as a way to combat Parkinson's disease."
The study does not offer answers to the question of why Zocor seems to work better than Lipitor in preventing Alzheimer's and Parkinson's diseases.
Is it time to start taking Zocor to prevent neurodegenerative diseases? Wolozin says people should take statins only to lower high cholesterol levels.
"If your parents got Alzheimer's disease and you have high cholesterol, you might want to talk with your doctor about whether you should take Zocor or Lipitor," Wolozin says. "If your parents don't have Alzheimer's disease, but, say, your dad had a heart attack, you should probably take Lipitor, because it is somewhat better at preventing some of the [problems ] associated with heart disease. You have to look at your own personal risk factors."
Proof of whether statins affect risk of Alzheimer's disease or Parkinson's disease can come only from controlled clinical trials. But as such trials would be extremely lengthy and expensive, Wolozin doubts they will be undertaken.
Help may come from ongoing trials looking at whether Lipitor or Zocor can help people who already have Alzheimer's disease. Those trials are nearly over; results are expected next year.
The Wolozin study appears in the July issue of the online journal BioMed Central Medicine.
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