Contrary to studies involving the not so elderly, researchers in the US found that use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as the painkillers ibuprofen and naproxen, did not delay the onset of Alzheimer’s or other forms of dementia in the very elderly.

The research was the work of scientists at the University of Washington, the Department of Veterans Affairs Medical Center and Group Health Cooperative, all in Seattle, and is published in the 22 April early online issue of Neurology.

People use NSAIDs to relieve pain from various conditions such as arthritis.

As other studies have suggested that NSAIDs may prevent Alzheimer’s, the Seattle researchers decided to examine if this was the case for an elderly group of people in the Adult Changes in Thought population-based cohort who were members of Group Health, an integrated healthcare delivery system with computerized pharmacy records from 1977 onwards.

All 2,736 participants were aged 65 or over (median age was 74.8), were taking or had taken NSAIDs in the past, and did not have dementia when they joined the study. The researchers followed the group for 12 years and noted any incidence of dementia with/without Alzheimer’s.

Using statistical regression models they then analyzed the links between dementia or Alzheimer’s onset with NSAID use and graded the results according to standard daily doses dispensed over 2 years. For example, heavy used would be SDD plus 500, or having been prescribed NSAIDs for 68 per cent of the time.

The participants’ healthcare pharmacy data was extensive and included prescribed and over the counter dispensing of NSAIDs. The researchers also looked at self-reported use of NSAIDs, as described by the participants during follow up.

The results showed that:

  • According to pharmacy records, 351 of the participants (12.8 per cent) had a history of heavy use of NSAIDs when they enrolled on the study.

  • Another 107 participants (3.9 per cent) became heavy users during follow up.

  • 476 participants (17.4 per cent) developed incident dementia, 356 with Alzheimer’s (median age of onset 83.5 and 83.8 respectively).

  • Heavy NSAID users (as defined by pharmacy records) showed increased incidence of dementia and Alzheimer’s.

  • The risk of developing any form of dementia was 66 per cent higher among heavy users compared to light users.

  • The risk of developing Alzheimer’s was 57 per cent higher among heavy NSAID users.

  • The adjusted hazard ratio for dementia was 1.66 (95 per cent confidence interval [CI] ranging from 1.24 to 2.24) and for Alzheimer’s it was 1.57 (95% CI 1.10-2.23).

  • The ratios did not change when the researchers took into account self-reported use of NSAIDs.

The researchers concluded that:

“These findings differ from those of other studies with younger cohorts. The results observed elsewhere may reflect delayed onset of Alzheimer dementia (AD) in nonsteroidal anti-inflammatory drug (NSAID) users.”

They sugggested that using NSAIDs to delay onset of Alzheimer’s in early old age could result in increased incidence in late old age.

More research is needed to discover how use of NSAIDs affects the development of Alzheimer’s, they wrote.

Co-author Dr Eric B Larson, executive director of Group Health Center for Health Studies told the press:

“Although we hoped to find a protective effect [from NSAIDs], 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,” he added.

Lead author Dr John CS Breitner, University of Washington professor of psychiatry and head of the Division of Geriatric Psychiatry at the VA Puget Sound Health Care System, said that one of the main differences between this study and previous research is this study examined older participants.

“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.”

The results of this study support such an explanation, but that is not the only one, cautioned Breitner, pointing out that:

“We must not ignore our main finding: increased risk of dementia in the NSAID users. We need further research to understand that more clearly,” he said.

“Risk of dementia and AD with prior exposure to NSAIDs in an elderly community-based cohort.”
J. C.S. Breitner, S. J.P.A. Haneuse, R. Walker, S. Dublin, P. K. Crane, S. L. Gray, and E. B. Larson.
Neurology published online April 22, 2009 as doi:10.1212/WNL.0b013e3181a18691.

Additional Sources: Group Health Cooperative Center for Health Studies.

Written by: Catharine Paddock, PhD