Public health interventions to reduce Alzheimer’s risk: Need for tailored approaches

Abstract

AbstractBackgroundWe have previously estimated that 30% of Alzheimer’s disease in the U.S. may be attributable to modifiable risk factors, and that the most important risk factors to target are physical inactivity, depression, and smoking. However, estimates in the U.S. population as a whole may not be ideal for guiding public health messaging about Alzheimer's risk reduction because they do not take into consideration the unique risk factor profiles of different regions. In this study, we estimate the proportion of Alzheimer’s disease cases that are potentially attributable to modifiable risk factors in California, which has the largest and most diverse population in the U.S.MethodWe calculated individual and combined population attributable risks (PARs) for Alzheimer’s disease in California for eight modifiable risk factors: physical inactivity, smoking, depression, low education, diabetes, midlife obesity, midlife hypertension, and hearing loss. Relative risks for each risk factor were extracted from recent meta‐analyses. Risk factor prevalence and communality were determined using data from the 2017 and 2018 California Behavioral Risk Factor Surveillance Survey, a population‐based survey weighted to provide representative estimates. To account for non‐independence of the risk factors, we estimated the communality and uniqueness of each risk factor via principal component analysis and applied them to Levin’s formula.ResultsIn California, the estimated PARs (95% confidence intervals) for modifiable risk factors were as follows: low education: 14.0% (13.3%, 14.8%), midlife obesity: 13.4% (12.9%, 13.9%), physical inactivity: 10.3% (9.8%, 10.8%), midlife hypertension: 7.4% (7.2%, 7.7%), depression: 7.4% (7.0%, 7.7%), diabetes: 6.7% (6.2%, 7.2%), smoking: 4.5% (4.2%, 4.8%), and hearing loss: 1.9% (1.7%, 2.1%). The combined PAR estimate was 29.4% (28.1%, 30.7%) incorporating the correlations between risk factors.ConclusionConsistent with our previous U.S. estimates, we found that about a third of Alzheimer’s disease cases in California might be attributable to modifiable risk factors. However, the most important risk factors differed, with low education, midlife obesity and physical inactivity contributing to the largest proportion of cases. Public health interventions to reduce dementia risk may be more effective if tailored to address the most important risk factors in the region.