Prevalence and determinants of self-reported all-cause dementia among middle-aged and older adults in the United States: Results from a nationally representative survey

Dementia encompasses a heterogeneous group of neurodegenerative and cerebrovascular disorders characterized by progressive cognitive decline that impairs memory, executive function, and activities of daily living. Although dementia includes multiple subtypes, nationally representative surveys often do not distinguish among them. Consequently, contemporary population-level estimates of self-reported all-cause dementia and its associated factors among middle-aged and older adults remain limited. This study estimated the prevalence of self-reported all-cause dementia and identified associated factors among middle-aged and older adults in the United States (U.S.). Secondary analyses used data from the National Health Interview Survey (NHIS), a nationally representative survey of the U.S civilian non-institutionalized population. Dementia status was ascertained via self-report using a binary indicator of whether respondents had ever been informed by a physician or other health professional that they had dementia. Survey-weighted descriptive statistics summarized participant characteristics. Univariate and multivariate sequential logistic regression models examined factors associated with dementia, with adjusted odds ratios (aORs) and 95% confidence intervals (CIs) presented in a forest plot. The analytical sample included 130,312 adults aged 40–85 years; 52.3% were women. The prevalence of self-reported all-cause dementia was 1.6% and increased with age and comorbidity burden. In fully adjusted regression models, female sex and overweight or obesity were associated with lower odds of all-cause dementia, whereas older age, lower educational attainment, residence in the west, multimorbidity, depression, anxiety, and enrollment in Medicaid or other public insurance programs were associated with higher odds of all-cause dementia. Approximately 1 in 100 middle-aged and older adults in the U.S reported a diagnosis of dementia. Sociodemographic, educational, physical, and mental health factors were independently associated with dementia. Public health strategies that promote education, improve management of chronic diseases, and strengthen mental health care may help reduce the burden of dementia in this population.