There hasn’t been much good news about Alzheimer’s lately, between the March announcement by Biogen and Esai that a promising trial of a potential drug treatment failed, and the July decision by Novartis and Amgen to stop their study of another class of therapies for the neurodegenerative disease.
But in a pair of studies presented at the annual Alzheimer’s Association International Conference on July 14, researchers reported encouraging results from studies of non-drug approaches.
In one, scientists led by Dr. Klodian Dhana at Rush University Medical Center in Chicago followed nearly 2,500 people for almost a decade while tracking several lifestyle factors: their diet, whether they smoked, the amount of leisure physical activity they completed each week, how much alcohol they drank and how much cognitive activity they engaged in. The researchers found that people who reported healthier lifestyles overall—those who stuck to a low-fat diet, did not smoke, exercised at least 150 minutes each week at moderate-to-vigorous levels, drank moderately and engaged in some late-life cognitive activities—had lower levels of Alzheimer’s dementia. In fact, the more healthy activities the people adhered to, the lower their risk. Compared to those who followed none or only one healthy lifestyle behavior, those following two or three of the healthy lifestyle factors reduced their risk of developing Alzheimer’s dementia by 39%, while those who followed four or five of the healthy behaviors reduced their risk by 59%.
Previous studies mostly focused on studying how individual factors such as diet or physical activity affected dementia risk, but this one advances that knowledge by showing that these factors may have an additive effect—the more activities people adopt, the lower their risk. And all of the factors included in the study are within people’s control, says Dhana. “The lifestyle factors we chose to study in this project are totally dependent on individuals so they can change them immediately if they want,” he says. “We were expecting to find a protective effect of these factors on dementia risk. But we were surprised by the magnitude of the effect.”
The association remained strong even after Dhana and his team adjusted for the possible effect of factors like age, education and genes that might predispose people to a higher risk of Alzheimer’s. In fact, when they limited their dataset to only those people with genetic risk factors such as ApoE4, they still found that those who adopted more healthy lifestyle behaviors had a lower risk of dementia than those who did not.
In another study, published July 14 in JAMA, as well as reported at the conference, an international team of researchers analyzed data from nearly 200,000 people enrolled in the UK Biobank study, a long-term study of older people that tracks a range of factors contributing to a variety of diseases including cancer, heart disease, depression and dementia. The scientists compiled a list of nearly 250,000 genetic variants that might have an effect on any type of dementia, including Alzheimer’s, and created a risk score for each after weighting their varying contributions to dementia risk. They also created a lifestyle score for all of the participants in the Biobank study based on four behaviors: smoking cigarettes, exercise, diet, and alcohol consumption. The idea was to tease apart how genetic risk factors and lifestyle factors contributed to dementia risk, and whether they interacted with each other in leading to dementia.
It turns out though, that overall, people with more genetic risk factors had a higher risk of developing dementia compared to those who had lower genetic risk scores, among people with the highest genetic risk, those who had more healthy behaviors were half as likely to develop dementia compared to people who also had high genetic risk but adopted fewer healthy activities.
“The core message from these findings is that whatever their genetic risk, people may be able to benefit from a healthy lifestyle,” says David Llewellyn from the University of Exeter and senior author of the study. The participants were grouped into low-, medium- and high-genetic risk, and in each group, those adhering to more healthy behaviors consistently showed a lower likelihood of developing dementia over the analysis period of eight years.
“It’s really reassuring in a way, since people say, ‘my parents had dementia so I probably inherited bad genes,’” says Llewellyn. “It’s important that people don’t fall into the trap of thinking that depending on your genes, dementia is inevitable. We found it’s not an all or nothing thing. The overall pattern of healthy behaviors and a healthy lifestyle can make a difference.”
The current study only focused on four behaviors, and Llewellyn notes there are others that may affect dementia risk, such as sleep, exposure to pollution, social engagement and cognitive activities, as well as having other diseases such as diabetes.
Dr. John Haaga, director of the division of behavioral and social research at the National Institute on Aging, which partially supported Llewellyn’s study, says the results should be especially reassuring given that the study participants were over 60 years old, and yet were still able to lower their dementia risk by adopting healthier behaviors. “That,” he says, “suggests that it’s never too late.”