ATMOSPHERE - Regular physical activity, eating a nutritional diet, and not smoking are all habits that have been well-established as ways to boost one’s overall health and longevity.
Five new research reports presented at the 2019 Alzheimer’s Association International Conference (AAIC) in July have provided further support for these lifestyle choices, finding that they may help prevent or delay cognitive decline and dementia.
The study authors found that participants who followed four to five of these lifestyle choices lowered their odds of developing Alzheimer’s by 60 percent. Even if an individual adopted just one element of the five, their risk would go down by 22 percent.
“The idea that combining multiple lifestyle factors together decreases risk is not necessarily new, but we’re seeing more rigorous data to support that,” says Rebecca Edelmayer, PhD, the director of scientific engagement at the Alzheimer’s Association.
Smoking and Alcohol Are Tied to Cognitive Decline
Two studies out of the University of California in San Francisco that were presented at the conference added to the continually growing evidence that smoking and drinking in excess are bad for you. These reports demonstrated that both habits also may contribute to mental decline.
In a long-term investigation that followed 3,364 adults over 25 years, scientists observed that “heavy stable” (or heavy) smokers were 1.5 to 2.2 times more likely to have cognitive impairment compared with nonsmokers. Those who quit smoking or were defined as “minimal stable” smokers had no increased risk of mental decline.
People who smoked a pack a day for more than 10 years were linked to a greater likelihood of poor cognitive function. The higher risk was even noted among midlife smokers in their forties.
In the second study, the scientists at UC San Francisco analyzed data regarding female veterans over the age of 55 who suffer from alcohol use disorder (AUD). The Committee on Prevention, Diagnosis, Treatment, and Management of Substance Use Disorders in the U.S. Armed Forces has declared that this substance abuse problem has become an epidemic among female military personnel.
Researchers compared 2,207 women veterans with AUD to 2,207 without the condition. Over an average follow-up period of 3.6 years, 4 percent of the population with AUD developed dementia versus 1 percent among those who did not have AUD — a more than threefold higher rate of cognitive trouble among those with a drinking problem.
“Smoking and drinking can potentially decrease the efficiency of blood flow, cardiovascular health, and the functioning of other organs, which can potentially have an impact on your brain cells,” says Dr. Edelmayer.
Healthy Choices May Help Overcome Genetic and Environmental Obstacles
A large investigation presented at AAIC and published July 14 in the Journal of the American Medical Association indicated that a healthy lifestyle may even help prevent or delay Alzheimer’s in people who are genetically predisposed to the disease.
Elzbieta Kuzma, PhD, a research fellow in neuroepidemiology at the University of Exeter Medical School, and her colleagues reviewed health data on almost 200,000 adults older than 60. Over an average follow-up of eight years, they identified 1,796 who developed dementia.
The researchers evaluated each participant’s genetic risk of Alzheimer’s on the basis of known gene mutations linked to the disease. The team also assessed each individual’s lifestyle factors, such as smoking status, alcohol consumption, level of physical activity, and diet.
Their findings showed that those with a high genetic risk and an unfavorable lifestyle were almost three times more likely to develop dementia compared with those with a low genetic risk and favorable lifestyle.
Living healthfully, however, made a difference for those with high genetic risk for dementia. Those in the high genetic risk category who followed a favorable lifestyle (compared with an unfavorable one) lowered their dementia risk by 32 percent.
“This research is exciting in that it shows there are actionable things we can do to try to counteract genetic risk for dementia,” said Dr. Kuzma in a press release.
A fifth study demonstrated that living in areas with higher levels of outdoor pollution is associated with a higher dementia risk, but that healthy habits may afford some protection.
Previous research speculated that tiny particles of air pollution may seep into the brain via the bloodstream.
In a University of Southern California study delivered at AAIC, authors examined a population of 6,113 women between the ages of 65 and 79 who did not have dementia at the beginning of the investigation. For 14 years, they were tested annually for dementia, and outdoor air pollution levels were evaluated around their homes. After an average of about nine years, 262 of the women were classified as having Alzheimer’s disease or related dementia.
The results confirmed that those exposed to higher levels air pollution were more likely to get dementia. Researchers, however, wanted to see if a person’s “cognitive reserve" might offer some protective effects against this mental decline even for those living in highly polluted areas.
Cognitive reserve is a term used to describe a resilient neural network in the brain. The concept was developed in the 1980s when scientists discovered plaques linked to Alzheimer’s in the brains of older individuals who had displayed no signs of dementia. Their autopsied brains showed all the physical signs of the disease in their brain but they could still think clearly when they were alive. Through further study, researchers came up with several factors that they believe contribute to this “brain stash.”
One’s cognitive reserve is now scored by evaluating factors such as educational attainment, brain size, and intelligence, as well as regular physical exercise, leisure activities, and social engagement.
In this investigation, the women with a higher cognitive reserve showed an increased risk of dementia because of living in polluted locations (21 percent greater), but their risk was not as great as those with a lower cognitive reserve (113 percent greater).
“You can’t always change a risk factor like where you live, but there is potential to overcome some of the risk; for example, through exercise and activities that may sharpen the mind,” says Edelmayer.
“What all this research really points to is keeping your body healthy as we’re aging, because it will be very supportive to our brain health in the future,” says Edelmayer.[EDH]