Suggesting that 40% of Dementia is the Result of Lifestyle and Environment
Researchers here run the numbers to suggest that as much of 40% of the incidence of dementia is the result of lifestyle choices and environmental factors, and thus amenable to prevention. A lot of these line items are known to contribute to the chronic inflammation of aging, and evidence increasingly leans towards an important role for unresolved, lasting inflammation in the progression of neurodegenerative conditions. Much of the focus is on hypertension, the raised blood pressure that is very damaging to fragile tissues such as those of the brain. Hypertension can be controlled to a large degree via changes in diet, weight, and exercise.
How much all-cause dementia could be prevented in the United States? Researchers attribute 41 percent of dementia cases to 12 modifiable lifestyle factors. Obesity, high blood pressure, and lack of exercise accounted for the lion's share. 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.
In the U.S. data, the three most prevalent factors - obesity, hypertension, physical inactivity - also had the largest population attributable fraction (PAF), each accounting for 20 percent of dementia risk. 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.
Adjusting for such correlations, researchers calculated that each factor directly explained 0.5 to 7.0 percent of the total modifiable risk. Obesity, hypertension, and physical inactivity still came out on top, each accounting for about 7.0 percent. Diabetes was a close fourth, at approximately 4.5 percent.
Link: https://www.alzforum.org/news/research-news/us-40-percent-all-cause-dementia-preventable