According to a study by American researchers, not all statins are alike in their ability to reduce chances of dementia and Alzheimer's disease.
In the online journal BMC Medicine , new findings suggest that simvastatin is associated with a lower incidence of dementia and Parkinson's disease. Disagreement over whether statins could guard against these conditions has meant the benefits to dementia sufferers to date have been unclear.
An international team led by Benjamin Wolozin, MD, at Boston University School of Medicine used data from the US Veterans Affairs Database, which contains diagnostic, medication and demographic information on 4.5 million subjects.
The researchers used statistical models to compare different statins, looking at data on over 700,000 simvastatin users and more than 50,000 atorvastatin users. The team targeted those aged 65 or over with no prior diagnosis of Alzheimer's disease, who had been taking statins for at least seven months.
The researchers found that for subjects aged 65 and over, simvastatin was linked with a significantly reduced number of cases of dementia and Parkinson's disease". The researchers also made the surprising finding that not all statins are equal when it comes to dementia or Parkinson's disease.
A small reduction in dementia cases was seen among those who regularly take atorvastatin, which did not reach a level of statistical significance. Lovastatin was not found to have any significant effect on dementia, and neither atorvastatin nor lovastatin were associated with a reduction in the number of cases of Parkinson's disease.
"The strength of reduction of incidence of dementia observed with simvastatin is striking," the authors write. Further studies should confirm that it is simvastatin's biological mode of action rather than a statistical bias at work. Previous research has studied whether statin treatment is beneficial for dementia sufferers or those at risk of dementia, but such research has lead to some conflicting results.
The current study gives more reliable results as it has considerable statistical power and incorporates existing data to investigate dementia and Parkinson's disease comprehensively.