Healthy Lifestyle Choices May Lower Risk of Cognitive Decline and Alzheimer’s Dementia, Research Shows

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by Patricia Inacio, PhD |

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lifestyle choices, dementia risk

Healthy lifestyle choices — maintaining an active mind, a nutritious diet, and regular exercise — may help protect against cognitive decline and dementia, new research shows.

Moreover, cigarette smoking and alcohol abuse seem to be associated with cognitive impairment and increased dementia risk.

These are the main findings of five studies presented at The Alzheimer’s Association International Conference 2019, held in Los Angeles from July 14–18.

“While there is no proven cure or treatment for Alzheimer’s, a large body of research now strongly suggests that combining healthy habits promotes good brain health and reduces your risk of cognitive decline,” Maria C. Carrillo, PhD, Alzheimer’s Association chief science officer, said in a press release.

This research “gives us attainable, actionable recommendations that can help us all live a healthier life,” Carrillo added.

In the study, “Impact of Healthy Lifestyle Factors on the Risk of Alzheimer’s Dementia; Findings from Two Prospective Cohort Studies,” researchers assessed the impact of five lifestyle choices — healthy diet, physical activity, no smoking, moderate alcohol intake, and maintaining an intellectually active lifestyle — on reducing the risk of Alzheimer’s.

Subjects included in the analysis participated in two studies, the Chicago Health and Aging Project (CHAP) and the Rush Memory and Aging Project (MAP), and were followed for a median of 9.1 years in CHAP and six years in MAP.

At follow-up, 20.5% participants in the CHAP study and 24.9% in the MAP study had incident Alzheimer’s dementia.

For each additional low-risk lifestyle factor, the risk of incident Alzheimer’s dementia was lower. Participants who adopted four out of the five lifestyle factors had a 59% lower risk for developing Alzheimer’s dementia compared with those that adopted one or none of the choices.

“This study highlights the importance of following multiple healthy lifestyle practices for lowering the risk of Alzheimer’s dementia,” said Klodian Dhana, MD, PhD, assistant professor at Rush University Medical Center in Chicago, and an author of the study.

“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,” Dhana added.

Another study, “Genetic Risk, Lifestyle and Dementia,” estimated the risk of all-cause dementia due to a combination of genetic and lifestyle factors in 157,369 UK Biobank participants, 60 or older, of European ancestry.

The risk of incident dementia was 60% higher among participants with a high genetic risk compared to those with a low genetic risk. However, these individuals had a 32% lower risk of developing all-cause dementia when following a healthy lifestyle.

Genetic risk with unhealthy lifestyle choices increased by almost three times a person’s risk for developing dementia when compared to those with a low genetic risk and healthy lifestyle.

“This research is exciting in that it shows there are actionable things we can do to try to counteract genetic risk for dementia,” said Elżbieta Kuźma, PhD, a research fellow at the University of Exeter Medical School, Exeter, UK. “In our study, adherence to a healthy lifestyle was associated with a reduced risk of dementia regardless of the genetic risk.”

More research is revealing that air pollution induces damage to the brain that translates into increased risk for Alzheimer’s and other dementias. In the study, “Heterogeneity in the Increased Risk for Alzheimer’s Disease and Related Dementias Associated with Fine Particle Exposure: Exploring the Role of Cognitive Reserve,” researchers at the University of Southern California assessed how cognitive stimulation modulated the link between air pollution exposure and Alzheimer’s risk. They followed women, 65 to 79 years old and free of dementia at enrollment, who were part of the Women’s Health Initiative Memory Study.

Among 6,113 women, 262 were classified as incident cases of Alzheimer’s disease and related dementias, at an average follow-up of 8.8 years.

Women living in areas of high air pollution had an increased risk for Alzheimer’s and other dementias. However, when divided according to their cognitive functioning scores, years of education, job status, and physical activity, the results showed that women with low cognitive reserve — the brain’s capacity to cope with the negative impact of brain damage on cognition — had a much higher risk (113%) of developing dementia, when compared to those with higher cognitive reserve (21% risk).

“Our study showed that engaging in physically and mentally stimulating activities is an important element of cognitive reserve, and the resulting benefit may offer protection against brain damage caused by outdoor air pollution exposure in late life,” said Diana Younan, PhD, a research associate at the University of Southern California.

Two other studies, “Early Adult to Mid-Life Cigarette Smoking and Cognitive Function: Findings from the Cardia Study” and “Alcohol Use Disorders in Female Veterans and the Impact on Dementia Risk,” reported the detrimental effects of smoking and alcohol abuse.

In the first study, researchers studied 3,364 adults from the Coronary Artery Risk Development in Young Adults study, who were followed for 25 years. Compared with never smoking, “having a heavy stable smoking trajectory consistently predicted poor cognitive performance,” the researchers wrote.

Smokers who quit and minimal smokers did not have an increased risk of cognitive impairment, but smoking a pack a day for more than 10 years was associated with poor cognitive performance.

Overall, the results revealed that cigarette smoking in early- to mid-life adulthood was associated with cognitive impairment.

“Our findings demonstrate that early adult to mid-life smoking may be associated with cognitive impairment much earlier than we expected,” said Amber Bahorik, PhD, at the University of California, San Francisco. “This adds to the already dense body of evidence showing continued smoking negatively impacts several health functions and emphasizes the benefits of quitting.”

In the second study, researchers followed a group of 2,207 female veterans, 55 or older, with alcohol use disorder (AUD) and 2,207 age-matched female veterans without AUD. The results showed that after a median follow-up of 3.6 years, 4% of women with AUD developed dementia compared with 1% without AUD.

“These findings highlight the need for providers to increase screening of both AUD and dementia in older women,” the researchers wrote.

“This study highlights the need to consider alcohol use, especially alcohol use disorder, when evaluating dementia risk profiles,” said Bahorik. “It also emphasizes the need for programs and services to address the growing problems of both AUD and dementia in older women.”