Combined 4-5 healthy behaviors linked to a 60% reduction in risk of Alzheimer’s disease

People in their 70s and 80s who adhere to four or five healthy lifestyle behaviors — a high-quality diet, regular physical activity, not smoking, light-to-moderate alcohol consumption and staying intellectually engaged — are 60 percent less likely to develop Alzheimer’s disease over the next decade of their life than people their age with fewer healthy habits, according to a study published Wednesday in the journal Neurology.

Adhering to even two or three of the behaviors lowers the risk as well — by 37 percent.

“This observational study provides more evidence on how a combination of modifiable behaviors may mitigate Alzheimer’s disease risk,” said Dr. Richard Hodes, director of the National Institute of Aging (NIA), in a released statement. Hodes was not an author of study, but his agency funded it.

About 5 million Americans have some form of dementia, including Alzheimer’s disease — a number that’s expected to triple to 14 million by 2060, according to the Centers for Disease Control and Prevention. Scientists aren’t sure what causes Alzheimer’s. Genetics — particularly having a variant of the apolipoprotein E (APOE) gene — appears to be a factor for some individuals, but lifestyle is also believed to play a role.

Research that has looked into the link between lifestyle behaviors (such as diet and exercise) and the risk of Alzheimer’s disease has tended to investigate those behaviors individually. Few studies have examined their synergistic effects on the risk of dementia.

The authors of the current study — a team led by Dr. Klodian Dhana, an assistant professor of geriatrics and palliative medicine at Rush University Medical College — decided to fill that research gap by assessing the risk of Alzheimer’s according to a combined score of healthy lifestyle behaviors.

Study details

For the study, Dhana and his colleagues analyzed data from two NIA-funded longitudinal studies: the Chicago Health and Aging Project (CHAP) and the Memory and Aging Project (MAP). They selected participants (1,845 from CHAP and 920 from MAP) whose data about diet, lifestyle factors and genetics (APOE status) were complete at the time they entered those projects.

The participants received an individual score (from 0 to 5, with 5 being the healthiest) based on their adherence to five lifestyle factors, each of which has been linked to cognitive health in previous research:

• Eating habits that mirror the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet. This diet emphasizes plant-based foods and limits servings of red meat, sweets, cheese, butter and fast/fried food.
• A minimum of 150 minutes per week of moderate- to vigorous-intensity physical activity (such as brisk walking)
• Not currently smoking
• Light-to-moderate alcohol consumption (no more than about one drink a day for women and two drinks a day for men)
• Engagement in late-life mentally stimulating activities (such as playing games, doing crafts, using the computer and engaging in social activities)

The participants were followed for an average of six years. During the follow-up period, 608 of them were diagnosed with Alzheimer’s disease.

When the researchers compared the healthy lifestyle scores with the Alzheimer’s diagnoses, they found that the risk of developing Alzheimer’s was 60 percent lower for those with scores of 4 or 5 and 37 percent lower for those with scores of 2 or 3 than for those with scores of 0 or 1.

Those associations held even after the researchers adjusted the data for body mass index (BMI) and for medical conditions such as diabetes and high blood pressure, which have also been linked to an increased risk of dementia.

Limitations and implications

Because this is an observational study, it can’t prove that adhering to healthy behaviors was protective against Alzheimer’s disease. As Dhana and his colleagues note in their paper, reverse causality cannot be ruled out. It could be that the participants who went on to have Alzheimer’s were in an early, undiagnosed phase of the disease when they entered the study, and the disease had caused them to engage in fewer healthy behaviors.

Also, the study wasn’t designed to determine which combination of the five healthy behaviors confers the greatest benefits.

Still, the findings are supported by other research that has linked each of the individual lifestyle behaviors to a lower risk of dementia, including among people with a genetic predisposition to the condition. A study published in 2019 found, for example, that people with a genetic risk for Alzheimer’s were about a third less likely to develop dementia if they followed a healthy lifestyle than if they didn’t.

Of course, as I’ve noted in Second Opinion before, it’s essential to remember that even if a healthy lifestyle can prevent dementia in some people, it is not able to do so for everyone. Some people will develop the condition no matter how conscientious they are about the foods they eat or the hours they exercise each week.

FMI: Even though this study was funded by taxpayers, you can access only an abstract of the study on Neurology’s website. The full study is behind a paywall.