According to a study recently published in Neurology, the medical journal of the American Academy of Neurology, seven healthy habits and lifestyle factors may help reduce the risk of dementia in people with the greatest genetic risk.
The seven cardiovascular and brain health factors are known as the American Heart Association’s Life’s Simple 7: being active, eating healthier, losing weight, not smoking, keeping healthy blood pressure, regulating cholesterol, and lowering blood sugar.
“These healthy habits in the Life’s Simple 7 have been linked to a lower risk of dementia overall, but it is uncertain whether the same applies to people with a high genetic risk,” said study author Adrienne Tin, Ph.D., of the University of Mississippi Medical Center in Jackson. “The good news is that even for people who are at the highest genetic risk, living by this same healthier lifestyle are likely to have a lower risk of dementia.”
In the research, 2,738 people with African heritage and 8,823 individuals with European ancestry were tracked over the course of 30 years. At the start of the trial, participants’ average age was 54.
The levels of each of the seven health factors were reported by study participants. The range of total scores was 0 to 14, with 0 being the most unhealthy score and 14 denoting the most healthy score. People of European heritage scored on average 8.3, whereas people of African descent scored on average 6.6.
Researchers calculated genetic risk scores at the start of the study using genome-wide statistics of Alzheimer’s disease, which have been used to study the genetic risk for dementia.
Participants with European ancestry were divided into five groups and those with African ancestry were divided into three groups based on genetic risk scores. The group with the highest genetic risk included people who had at least one copy of the APOE gene variant associated with Alzheimer’s disease, APOE e4. Of those with European ancestry, 27.9% had the APOE e4 variant, while of those who had African ancestry, 40.4% had the APOE e4 variant. The group with the lowest risk had the APOE e2 variant, which has been associated with a decreased risk of dementia.
By the end of the study, 1,603 people with European ancestry developed dementia and 631 people with African ancestry developed dementia.
For people with European ancestry, researchers found that people with the highest scores in the lifestyle factors had a lower risk of dementia across all five genetic risk groups, including the group with the highest genetic risk of dementia. For each one-point increase in the lifestyle factor score, there was a 9% lower risk of developing dementia.
Among those with European ancestry, compared with the low category of the lifestyle factor score, the intermediate and high categories were associated with 30% and 43% lower risk for dementia, respectively. Among those with African ancestry, the intermediate and high categories were associated with 6% and 17% lower risk for dementia, respectively.
Among people with African ancestry, researchers found a similar pattern of declining dementia risk across all three groups among those with higher scores on the lifestyle factors. But researchers said the smaller number of participants in this group limited the findings, so more research is needed.
“Larger sample sizes from diverse populations are needed to get more reliable estimates of the effects of these modifiable health factors on dementia risk within different genetic risk groups and ancestral backgrounds,” Tin said.
A limitation of the study was the smaller sample size among people of African ancestry and that many African American participants were recruited from one location.
The study was supported by the National Heart, Lung, and Blood Institute, the National Institutes of Health, the Department of Health and Human Services, and the National Human Genome Research Institute.
Reference: “Genetic Risk, Midlife Life’s Simple 7, and Incident Dementia in the Atherosclerosis Risk in Communities Study” by Adrienne Tin, Jan Bressler, Jeannette Simino, Kevin J Sullivan, Hao Mei, B. Gwen Windham, Michael Griswold, Rebecca F. Gottesman, Eric Boerwinkle, Myriam Fornage and Tom H. Mosley, 25 May 2022, Neurology.