Aspirin and related painkillers called non-steroidal anti-inflammatory drugs all seem to work equally well to cut a person's risk of developing Alzheimer's disease, researchers said.
The researchers examined data from six studies involving 13,499 people to gauge the protective effect from these commonly used drugs, called NSAIDs, on Alzheimer's risk.
Over the course of the studies, 820 of the people in the studies developed the disease.
Those who used NSAIDs, a class of pain-relieving drugs including aspirin, ibuprofen (Advil, Motrin and other brands) and naproxen (Aleve and other brands), collectively had a 23 percent lower risk for Alzheimer's in comparison to people who did not use these drugs.
But even though different types of NSAIDs have different properties, they delivered essentially the same level of risk reduction, the researchers wrote in the journal Neurology Wednesday.
"When we looked at different sub-groups (of NSAIDs), we found no evidence that there was any difference in the reduction in risk," Peter Zandi of Johns Hopkins University in Baltimore said in a telephone interview.
Alzheimer's disease is the most common form of dementia among older people, and researchers have been working to understand its causes and risk factors and ways to reduce a person's chance of developing it.
It has been linked with inflammation, the process particularly targeted by NSAIDS. But they also have other, broad effects on the body.
Zandi said some previous research had suggested that ibuprofen may be provide a particular protective effect because it might guard against a type of plaque found in the brains of people with Alzheimer's disease.
"But that's not what we found," Zandi said, noting that ibuprofen delivered protection no better or worse than the others in this class of drugs.
"It's left us with a little bit of a mystery," Zandi said.
Inconsistent results
Researchers in the field have been cautioning people against taking these drugs specifically to ward of Alzheimer's until further studies are done to clarify the effects.
Zandi noted that previous research has delivered inconsistent results on the question of whether these drugs offer any protection against Alzheimer's.
Earlier this month, researchers including Dr. Steven Vlad of Boston University School of Medicine reported the results of a different study finding that people who took ibuprofen had a 40 percent lower risk of Alzheimer's disease, while those who took other NSAIDs cut their risk by about 25 percent.
Those findings were based on data on about 49,000 U.S. military veterans who developed Alzheimer's and nearly 200,000 who had no form of dementia.
But another study published earlier this month led by Barbara Martin of Johns Hopkins found that NSAIDs did not appear to ward off the mental decline associated with the onset of Alzheimer's disease.
Alzheimer's disease starts out with mild memory loss and confusion, but escalates into profound memory loss and an inability to care for oneself. It is incurable and fatal.
