May 5, 2009
Popular painkillers like ibuprofen and naproxen did nothing to prevent the onset of Alzheimer's disease in elderly men and women who were taking the drugs for arthritis and other painful conditions. In fact, those taking the medicines were more likely to develop Alzheimer's or other forms of dementia than those who weren't taking the pain relievers. This doesn't mean that the pain relievers caused Alzheimer's. But it does mean they didn't ease the condition.
The findings add to a mix of conflicting findings on whether the popular pain relievers known as Nsaids, for nonsteroidal anti-inflammatory drugs, help to ward off the onset of Alzheimer's. The popular drugs are sold over-the-counter and in prescription form under such brand names as Advil, Motrin, Aleve and Naprosyn. The findings appeared in Neurology, the medical journal of the American Academy of Neurology.
Some earlier research has suggested that Nsaids lead to a lower likelihood of Alzheimer's. Other studies, however, have shown that the drugs provide no protective benefits.
The current study looked at men and women who were older than most of those studied in earlier research. The average age of study participants at the start of the study was 75, and they were followed for 12 years, into their late 80s and older. Most of those who developed Alzheimer's during the study were older than 83 at the time they learned they had the illness.
All belonged to Group Health, an integrated health-care plan in the Seattle area, and their drug prescriptions and over-the-counter drug use were monitored over the 12-year study period. Those who were so-called "heavy users" of Nsaid pain relievers were 66 percent more likely to develop Alzheimer's or other forms of dementia than those who used little or none of the drugs. Heavy-users of Nsaids were defined as those who were on the medications for about two-thirds of the time over a two-year period.
Why would those using the most Nsaids wind up with more Alzheimer's? Alzheimer's disease is believed to involve inflammation in parts of the brain. Those who took the most Nsaids might have been more prone to having the type of inflammation found in Alzheimer's in addition to inflammation in joints or muscles. But the fact is, nobody really knows at this time.
The study found that among all the participants, 351 people had a history of using Nsaids heavily at the study's start, and another 107 became heavy Nsaid users during the follow-up period. During the study, 476 people developed Alzheimer's disease or dementia.
"Nsaids are useful for relieving pain from conditions including arthritis," said study author Eric B. Larson, M.D., M.P.H., executive director of Group Health Center for Health Studies. "Although we hoped to find a protective effect, there was none. Thus, for this age group, there's no basis for taking Nsaids to prevent Alzheimer's disease. Our study in this quite elderly population showed more risk of dementia with Nsaids, especially when used heavily."
The researchers are unclear why some earlier studies found a possible brain-protective benefit from Nsaid use. And even those studies that found that pain relievers did not help against Alzheimer's did not suggest they increased risk for the disease. One explanation may be because the patients in this study tended to be much older than those observed in earlier research. Another is that different Nsaids were used. Earlier studies suggested that only certain types of Nsaids might be beneficial in Alzhiemer's.
"A key difference between this study and most of those done earlier is that our participants were older," said lead study author John C. S. Breitner, M.D., M.P.H., University of Washington professor of psychiatry and head of the Division of Geriatric Psychiatry at the Veterans Affairs Puget Sound Health Care System. "It has been argued for some time that Nsaid use delays the onset of Alzheimer's disease. If so, studies of younger Nsaid users would show fewer Alzheimer's cases, while groups of older people might show more cases, including those that would have happened earlier if they had not been delayed."
"This is one interpretation of the results, but other explanations are possible," Dr. Breitner cautioned. "We must not ignore our main finding: increased risk of dementia in the Nsaid users. We need further research to understand that more clearly."
In the meantime, experts do not advise taking regular doses of Nsaid pain relievers as a preventive against Alzheimer's. Like all drugs, the medicines can have serious side effects, like kidney damage or internal bleeding. At the same time, if you are taking the drugs for painful conditions like arthritis and joint pain, you should continue to take them under your doctor's supervision.
J. C.S. Breitner, S. J.P.A. Haneuse, R. Walker, S. Dublin, P. K. Crane, S. L. Gray, and E. B. Larson: "Risk of dementia and AD with prior exposure to NSAIDs in an elderly community-based cohort." Neurology, 2009; (in press) DOI: 10.1212/WNL.0b013e3181a18691