Statins are one of the most largely prescribed medications, but how effective they are in preventing or controlling Alzheimer’s Disease (AD) remains unclear. “Several studies have suggested that statin users were less likely to have AD, while others have not. Further, little is known about the relation of statins to the principal manifestation of AD, cognitive decline,” states a recent study on the matter, which found no direct connection between the two.
Statins are defined in the study as “3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, which block a key enzyme in the cholesterol synthesis pathway, and are known to have multiple actions.” The studies that have shown a connection between statins and AD have primarily been done on animals or isolated cells, which has been part of the problem in finding a conclusive connection or lack there of.
“Although cell and animal studies have suggested a protective effect of statins against pathogenic mechanisms important in AD, little data are available on the relation of statins to AD pathology using human postmortem brain tissue from persons well-characterized during life.” The study under analysis here did use human brain tissue, likely to be more representative of the connection between statins and AD.
The study was done under the umbrella of the “Religious Orders Study,” intended to be a comprehensive study of dementia. 900 elderly people, who had no signs of dementia at the beginning of the study, were followed and observed for 12 years.
The study “first examined relations of statins to clinical outcomes of incident AD and change in cognition, including global cognition and five different cognitive domains.” This was followed by “examined relations of statins to AD pathology and cerebral infarction, two common pathologic causes of dementia, in more than 250 persons who died during the study and on whom neuropathologic data were available.” The availability of this “postmortem” brain tissue of these 250 deceased individuals is what makes this study so compelling.
In the 12 years of the study, 191 of the patients developed dementia, and the use of statins (between 12-18%) during the 12 years was found to have no connection in preventing the development of AD. In addition, no direct connection was found between statin use and “change in global cognition, or five separate cognitive domains.”
As stated above, the use of statins as a preventative measure for AD is a controversial issue, and this study does not conclusively solve the problem. Nonetheless, being one of the only studies done on actual human brain tissue, the “negative” results do hold a lot of weight. If the same conclusion of no connection between statin use and AD prevention is found by other similar studies, there is a strong likelihood that statins will not be prescribed for this purpose nearly as often.
Source: Defeat Diabetes Foundation