Two new studies presented recently at the Alzheimer's Association International Conference affirm the potential for a healthy lifestyle to reduce the risk of age-related dementia and cognitive decline. The research particularly suggests lifestyle factors can counteract genetic predispositions for Alzheimer's disease.
The first study, led by scientists from the University of Exeter, looked at nearly 200,000 adults enlisted in the UK Biobank. Utilizing prior Alzheimer's genetic studies, the researchers generated polygenic risk scores for those subjects in the Biobank that were identified as having a genetic risk for developing dementia. Lifestyle was then categorized by four factors: smoking status, frequency of physical activity, diet, and alcohol consumption.
Unsurprisingly, those with a high genetic risk and an unhealthy lifestyle were significantly more likely to develop dementia than those with a low genetic risk and healthy lifestyle. However, the researchers did discover that all cases of dementia could be notably reduced by a healthy lifestyle, regardless of genetic risk factors. In fact, healthy lifestyle behaviors were found to reduce dementia cases by 32 percent in the high genetic risk group.
"This is the first study to analyze the extent to which you may offset your genetic risk of dementia by living a healthy lifestyle," says Elżbieta Kuźma, joint lead author on the study. "Our findings are exciting as they show that we can take action to try to offset our genetic risk for dementia. Sticking to a healthy lifestyle was associated with a reduced risk of dementia, regardless of the genetic risk."
Carol Routledge, from Alzheimer's Research UK, suggests these findings are important in changing the public perception of dementia risk factors. Routledge says only a third of adults think lifestyle factors can reduce a person's risk of developing dementia, and while genes are relevant, our behaviors can significantly improve our odds of living a healthy cognitive life well into our older years.
"Sadly, as genetics still plays an important role in influencing the risk of Alzheimer's, there will always be people who address many or all of these lifestyle factors and still develop the disease," says Routledge. "While we can't change the genes we inherit, this research shows that changing our lifestyle can still help to stack the odds in our favor."
The second study, from Rush University, took a more granular approach at examining how lifestyle factors influence the onset of Alzheimer's disease. Over 2,000 subjects were tracked for an average of nine years. Five specific healthy lifestyle factors were examined in this study: healthy diet, 150 minutes per week of exercise, only light to moderate alcohol consumption, engaging in cognitively stimulating activity, and not smoking.
The researchers discovered that adopting at least four of those lifestyle factors lowered a person's risk of developing Alzheimer's by 60 percent, compared to those who did none, or just one, of those behaviors. Klodian Dhana, one of the Rush University scientists working on this research, suggests public health policies could have significantly positive outcomes if these five lifestyle behaviors were prominently promoted.
"This study highlights the importance of following multiple healthy lifestyle practices for lowering the risk of Alzheimer's dementia," says Dhana. "In the U.S., adherence to a healthy lifestyle is low, and therefore promoting these lifestyle factors should become the primary goal for public health policies."
While it certainly isn't a major newsflash to claim exercising, quitting smoking, and eating better can confer beneficial health outcomes, the new studies do offer a reassuring suggestion that, despite one's genetic proclivities, we can potentially avoid, or slow, cognitive decline in later life by making some simple lifestyle modifications.
The University of Exeter genetic risk study was published in the journal JAMA.
Sources: University of Exeter, Alzheimer's Association International Conference