Association of Co-occurring Dementia and Self-reported Visual Impairment with Activity Limitations in Older Adults

Importance: The number of older adults with visual impairment (VI) and dementia is projected to increase in the US because of the aging of the population. Dementia and VI commonly co-occur and are each independently associated with disability. To care for an aging population, it may be important to characterize the association of coexisting dementia and self-reported VI on daily functioning. Objective: To evaluate the association of co-occurring dementia and self-reported VI on daily functioning. Design, Setting, and Participants: This cross-sectional analysis of a nationally representative cohort study used data from the National Health and Aging Trends Study (NHATS), an annual study of US adults 65 years and older. Participants in the 2015 survey with complete data on outcomes, associated factors, and covariates were included in this study. Data analysis took place from January 2019 to November 2019. Main Outcomes and Measures: Multivariable Poisson regression was used to model the independent associations and interaction of dementia and self-reported VI status on 3 functional activity scales (self-care, mobility, and household activities). Marginal predicted proportions were calculated. Analyses were adjusted for sociodemographic and medical factors and accounted for the complex survey design. Results: A total of 7124 participants were included. The weighted proportion of female respondents was 55.3% (95% CI, 54.0%-56.6%), and 56.1% (95% CI, 54.1%-58.1%) were between 65 and 74 years old. Self-reported VI was present in 8.6% (95% CI, 7.8%-9.3%) of participants, while 8.3% (95% CI, 7.8%-8.9%) had possible dementia and 6.3% (95% CI, 5.7%-6.9%) had probable dementia. Self-reported VI was associated with an expected decrease in mobility score of 14.7% (functional scale scores: no VI, 10.82 vs VI, 9.23), self-care score of 9.5% (no VI, 14.54 vs VI, 13.16), and household activity score of 15.2% (no VI, 18.23 vs VI, 15.45), while probable dementia was associated with expected decreases of 27.8% (no dementia, 10.82 vs probable dementia, 7.81), 22.9% (no dementia, 14.54 vs probable dementia, 11.20), and 34.7% (no dementia, 18.23 vs probable dementia, 11.90), respectively. Among those with probable dementia and self-reported VI, there was an expected decrease in mobility score of 50.1% (functional ability scores: no VI and no dementia, 10.82 vs VI and probable dementia, 5.40), self-care score of 42.4% (no VI and no dementia, 14.54 vs VI and probable dementia, 8.38), and household activity score of 52.4% (no VI and no dementia, 18.23 vs VI and probable dementia, 8.68), suggesting that respondents with co-occurring dementia and self-reported VI had lower functional activity scores than would be associated with the independent contributions of these conditions. Conclusions and Relevance: Older adults with both dementia and self-reported VI may be at high risk for disability, and their co-occurrence may potentiate this risk. These findings suggest that the growing population of older adults with both visual impairment and dementia may benefit from interventions to maximize vision and cognition and promote functioning and independence.