NEW YORK (Reuters Health) – In the largest cohort study to date, statin treatment was found to reduce the incidence of Alzheimer’s disease, regardless of the drug’s lipophilicity or the individual’s apolipoprotein E genotype.

Numerous studies have looked at the relationship between statin use and the development of Alzheimer’s disease, with conflicting results. One explanation for the inconsistencies is that “only the lipophilic statins, which could cross the blood-brain barrier more easily, would affect brain cholesterol metabolism.”

In the December issue of the Journal of Neurology, Neurosurgery and Psychiatry, Dr. M. M. B. Breteler and colleagues at the Erasmus Medical Centre in Rotterdam, the Netherlands, explored these issues using data from the prospective, population-based Rotterdam Study. The analysis included 6992 subjects, 55 years old or older, who were free of dementia when examined between 1990 and 1993.

During follow-up until 2005 (mean 9.2 years), 582 subjects were diagnosed with Alzheimer’s. After controlling for sociodemographic and clinical factors, statin users had a significantly reduced risk of AD compared with those who never used statins (adjusted hazard ratio 0.57).

The protective effect was similar for lipophilic and hydrophilic statins, and for persons with and without an apolipoprotein E-epsilon-4 allele.

On the other hand, the use of other cholesterol-lowering drugs (fibrates, bile-acid binding resins or nicotinic acid and derivatives) failed to exhibit similar benefit.

“All in all,” Dr. Larry Sparks at the Sun Health Research Institute in Sun City, Arizona, writes in an accompanying editorial, “it is clear that somewhere between normal cognitive performance and profound dementia of Alzheimer’s disease, statin therapy exerts a beneficial effect.”

He points out that nearly 20 previous studies have assessed the effect of statin use on later risk of Alzheimer’s disease in older people, and the majority found substantial benefit.

Dr. Sparks concludes that “it is our task to identify at what point in time statin therapy might be of the greatest benefit in order to effectively target which patients to treat with cholesterol-lowering statins.”

Reference:
J Neurol Neurosurg Psychiatry 2009;80:1-2,13-17.