Scientists pinpoint the eight key lifestyle factors drive Alzheimer's risk. Obesity, exercise and education top the list.
By 2050, it is estimated that 153 million people worldwide — more than one in every 100 — will be living with Alzheimer’s. While the genetic risks associated with Alzheimer’s are — at least so far — beyond human control, there are other key risk factors for this fatal neurodegenerative disease. A few in particular, new research says, are lifestyle factors we can control. In some cases, controlling for these factors with lifestyle changes might even be able to prevent Alzheimer’s altogether.
The new study, published in JAMA Neurology, points to eight modifiable risk factors. One or more of these eight factors appear to be linked to one in every three U.S. cases of Alzheimer’s. These risk factors varied across race and sex within the study. While the researchers caution that these factors don’t necessarily cause Alzheimer’s, they may still play an important role in the development of the disease.
The eight risk factors identified in the study are:
- Midlife obesity
- Low physical activity or lack of exercise
- Low educational attainment
- Midlife hypertension
- Depression
- Diabetes
- Smoking
- Hearing loss
Of these eight, three rose to the top of the list, appearing to have the strongest links to the disease, according to the lead author Dr. Roch A. Nianogo, assistant professor at the University of California, Los Angeles.
“About 10 years ago, when we conducted the initial study, we found that the top three modifiable risk factors that were associated with Alzheimer’s disease and other dementias were physical inactivity, depression and smoking,” Nianogo told Being Patient. “Today, the top three factors are now midlife obesity, physical inactivity, and low education.”
How sex and ethinicity impact the risk of Alzheimer’s
To conduct the study, researchers analyzed data from 378,615 participants in the 2018 Centers for Disease Control and Prevention Behavioral Risk Factor Surveillance System.
The total risk attributed to these factors was higher in men than in women, though women account for the majority of Alzheimer’s and dementia cases. Depression also contributed more to Alzheimer’s risk in women than in men.
“We think this could be due to the fact that women tend to live longer than men on average and older age is one of the most important risk factors for developing Alzheimer’s disease and related dementias,” Nianogo said.
In addition, there were differences in risk scores between people from different races and ethnicities.
- American Indian and Alaska Native individuals: Risk factors linked to 39 percent of cases
- Asian individuals: Risk factors linked to 16 percent of cases
- Black individuals: Risk factors linked to 40 percent of cases
- Hispanic individuals: Risk factors linked to 34 percent of cases
- White individuals: Risk factors linked to 29 percent of cases
Midlife obesity was the most prominent such risk factor for American Indians, Alaska Natives, Black, and white individuals. For Hispanic individuals, the largest risk factor was low educational attainment. For Asian individuals, the largest risk factor was physical inactivity.
“We think this is mainly due to the difference in the prevalence of risk factors across different racial and ethnic groups,” Nianogo said. “Unfortunately, our study does not account for differences in diagnosis between these different communities.”
Lowering your risk of Alzheimer’s
This study highlights the importance of staying healthy and ensuring equitable access to schools. did highlight some limitations of the work however.
Many of the estimates used to measure the association between risk factors and Alzheimer’s came from observational studies. “While they could reflect the true effect of what is really happening, they could also reflect the effect of other factors not accounted for in our study,” Nianogo said.
Fortunately, there are effective interventions that can alleviate some of the burden of the three main risk factors. For instance, eating a Mediterranean-style diet rich in fiber, vegetables, nuts and seeds, and fish oils, as well as exercise can keep your brain healthy longer.
Experts acknowledge that more research across different racial and ethnic communities would help identify targeted interventions and policy changes that can further reduce the risk.
While there are ways to counter risk factors like physical inactivity, other factors are challenging to modify.
“Educational attainment can be difficult to change and that is why prevention is important,” Nianogo said. “Making sure everyone receives adequate education is critical to preventing Alzheimer’s disease and other dementias.”
