Simvastatin linked with risk of incidence of dementia, Parkinson's disease

Simvastatin produces a major reduction in the incidence of dementia and Parkinson disease, which is not observed in other statins, according to new findings. Using three models for analysis of a US prescribing database, Dr Benjamin Wolozin (Boston University School of Medicine, Massachusetts) and colleagues examined the incidence of dementia and Parkinson's disease among subjects who had continuously used a statin (lovastatin, simvastatin and atorvastatin) for at least seven  months. The Veterans Affairs database included diagnostic, medication, and demographic information on 4.5 million subjects, 94.4% of whom were men. After adjusting for co-variates the researchers found simvastatin was linked with significant reductions in the incidence of dementia using any of the three models. The first model incorporated adjustment for age, the second model included adjustments for three known risk factors for dementia, hypertension, cardiovascular disease or diabetes, and the third model incorporated an adjustment for the Charlson index, which is an index that provides a broad assessment of chronic disease Atorvastatin showed a reduction in the hazard ratio that was significant in model one, borderline in model two, and not significant in model three. Lovastatin was not associated with a reduction in the incidence of dementia for any model. Using model three, the hazard ratios for incident dementia for simvastatin and atorvastatin were 0.46 (CI 0.44 - 0.48, p<0.0001) and 0.91 (CI 0.80 - 1.02, p=0.11), respectively. Wolozin's group admits to being surprised by the size of the effect associated with simvastatin and that it worked for both Parkinson's disease and dementia. The authors were also surprised that atorvastatin minimal impact on the incidence of either disease. The investigators suggest that brain penetration and potency differences between the statins may explain some of their findings and call for further prospective studies to confirm the results. Reference Wolozin, B. Wang, S. Li, NC. et al. 2007. ‘Simvastatin is associated with a reduced incidence of dementia and Parkinson's disease’. BMC Medicine, vol. 5, article; 20....