In the U.S., 40 Percent of All-Cause Dementia Is Preventable
The saying is "What's good for the heart is good for the brain." These studies are based on cross-sectional surveys, so there are limitations.
>>This estimate is on par with a Lancet Commission report linking 40 percent of dementia cases worldwide to the same 12 risk factors: physical inactivity, excess alcohol consumption, obesity, smoking, hypertension, diabetes, depression, traumatic brain injury, hearing loss, few years of education, social isolation, and air pollution. However, the report pegged hearing loss, education, and smoking as the three largest ones (Aug 2020 conference news). Lee’s work highlights the epidemiological differences between the United States and other countries.
In the U.S. data, the three most prevalent factors—obesity, hypertension, physical inactivity—also had the largest PAF, each accounting for 20 percent of dementia risk (see image below). Other common risk factors carried lower risk. Air pollution ranked fifth in prevalence but came in second to last as a risk factor, explaining only 2.2 percent of preventable dementia. Excessive alcohol consumption, defined as drinking more than 14 standard drinks per week, accounted for 0.7 percent. These “unweighted” numbers did not take into account that some risks correlate with each other. For example, physical inactivity increases a person’s chances of gaining weight or having high blood pressure, or obesity increases a person's odds of developing diabetes.
Deborah Barnes, University of California, San Francisco, and colleagues recently found much the same in about 380,000 American adults who answered the U.S. Behavioral Risk Factor Surveillance Survey (Nianogo et al., 2022). Eight dementia risk factors—physical inactivity, midlife obesity, smoking, midlife hypertension, diabetes, depression, hearing loss, and few years of education—correlated to 37 percent of dementia risk in the United States, with obesity, physical inactivity, and few years of education topping the charts. Blacks, Hispanics, and American Indians/Alaska Natives had higher prevalence of risk factors than Caucasians or Asians.<<
