Modifiable Risk Factors for Alzheimer Disease and Related Dementias Among Adults Aged ≥45 Years — United States, 2019

Alzheimer disease,* the most common cause of dementia, affects an estimated 6.5 million persons aged ≥65 years in the United States (1). A growing body of evidence has identified potential modifiable risk factors for Alzheimer disease and related dementias (ADRD) (1–3). In 2021, the National Plan to Address Alzheimer’s Disease (National Plan) introduced a new goal to “accelerate action to promote healthy aging and reduce risk factors for Alzheimer’s disease and related dementias” to help delay onset or slow the progression of ADRD (3). To assess the status of eight potential modifiable risk factors (i.e., high blood pressure, not meeting the aerobic physical activity guideline, obesity, diabetes, depression, current cigarette smoking, hearing loss, and binge drinking), investigators analyzed data from the cognitive decline module that was administered to adults aged ≥45 years in 31 states and the District of Columbia (DC)^† in the 2019 Behavioral Risk Factor Surveillance System (BRFSS) survey. Among the risk factors, prevalence was highest for high blood pressure (49.9%) and lowest for binge drinking (10.3%) and varied by selected demographic characteristics. Adults with subjective cognitive decline (SCD),^§ an early indicator of possible future ADRD (4), were more likely to report four or more risk factors than were those without SCD (34.3% versus 13.1%). Prevalence of SCD was 11.3% overall and increased from 3.9% among adults with no risk factors to 25.0% among those with four or more risk factors. Implementing evidence-based strategies to address modifiable risk factors can help achieve the National Plan’s new goal to reduce risk for ADRD while promoting health aging.^¶,**

BRFSS is a cross-sectional, random-digit–dialed, annual telephone survey of noninstitutionalized U.S. adults aged ≥18 years. BRFSS is administered by state and territorial health departments, and responses are weighted to produce data representative of each state. The 2019 combined (landline and mobile) median response rate was 49.4%.^†† In 2019, the cognitive decline module was administered to adults aged ≥45 years in 31 states and DC.

Eight modifiable risk factors were assessed: high blood pressure, not meeting the aerobic physical activity guideline, obesity, diabetes, depression, current cigarette smoking, hearing loss, and binge drinking.^§§ The total number of risk factors per respondent was defined as the sum of any risk factors reported and was grouped into no, one, two, three, or four or more risk factors. Respondents were classified as experiencing SCD if they responded “yes” when asked if they had experienced worsening or more frequent confusion or memory loss in the previous 12 months. Data were collected from 161,941 respondents; 21,865 (13.5%) respondents who refused to respond to the question assessing SCD or who responded, “don’t know/not sure,” were excluded. Respondents with missing data for risk factors (ranging from 0.2% for diabetes to 8.8% for obesity) were excluded from corresponding prevalence estimate calculations.

Prevalence of each modifiable risk factor was estimated overall and by SCD status and selected demographic characteristics. The proportion of respondents with no, one, two, three, or four or more risk factors was determined by SCD status. Prevalence of SCD was determined among respondents with and without each risk factor and by number of risk factors. All percentages were weighted and unadjusted. Analyses were conducted using SAS-callable SUDAAN (version 9.4; SAS Institute) to account for complex survey design and weighting. T-tests were used to determine statistically significant differences by subgroup (p<0.05). All estimates met reliability standards by having a relative SE <30%. This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.^¶¶

In 2019, the prevalence of SCD among adults aged ≥45 years in 31 participating states and DC was 11.3% (Table 1). The most common modifiable risk factor for ADRD was high blood pressure (49.9%), followed by not meeting the aerobic physical activity guideline (49.7%), obesity (35.3%), diabetes (18.6%), depression (18.0%), current cigarette smoking (14.9%), hearing loss (10.5%), and binge drinking (10.3%). The prevalences of risk factors varied by selected demographic characteristics, including race and ethnicity. For example, the prevalence of several risk factors was higher among adults who were American Indian or Alaska Native, non-Hispanic Black or African American, or Hispanic, than among non-Hispanic White adults. Adults with SCD were more likely to report most of the modifiable risk factors and were more likely to report four or more risk factors (34.3%) than were those without SCD (13.1%) (Figure).

Adults with each modifiable risk factor, except for binge drinking, were more likely to report SCD than were those without the risk factor (Table 2). Prevalence of SCD ranged from a high of 28.5% among persons with depression and 24.7% among those with hearing loss to 11.3% among those who reported binge drinking. SCD prevalence increased from 3.9% among those with no risk factors to 25.0% among those with four or more risk factors.