Association of Race and Ethnicity With Incidence of Dementia Among Older Adults

Abstract

IMPORTANCEThe racial and ethnic diversity of the US, including among patients receiving their care at the Veterans Health Administration (VHA), is increasing. Dementia is a significant public health challenge and may have greater incidence among older adults from underrepresented racial and ethnic minority groups.OBJECTIVE To determine dementia incidence across 5 racial and ethnic groups and by US geographical region within a large, diverse, national cohort of older veterans who received care in the largest integrated health care system in the US.DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study within the VHA of a random sample (5% sample selected for each fiscal year) of 1 869 090 participants aged 55 years or older evaluated from October 1, 1999, to September 30, 2019 (the date of final follow-up).EXPOSURES Self-reported racial and ethnic data were obtained from the National Patient Care Database. US region was determined using Centers for Disease Control and Prevention (CDC) regions from residential zip codes. MAIN OUTCOMES AND MEASURES Incident diagnosis of dementia (9th and 10th editions of the International Classification of Diseases).Fine-Gray proportional hazards models were used to examine time to diagnosis, with age as the time scale and accounting for competing risk of death. RESULTSAmong the 1 869 090 study participants (mean age, 69.4 [SD, 7.9] years; 42 870 women [2%]; 6865 American Indian or Alaska Native [0.4%], 9391 Asian [0.5%], 176 795 Black [9.5%], 20 663 Hispanic [1.0%], and 1 655 376 White [88.6%]), 13% received a diagnosis of dementia over a mean follow-up of 10.1 years. Age-adjusted incidence of dementia per 1000 person-years was 14.2 (95% CI, 13.3-15.1) for American Indian or Alaska Native participants, 12.4 (95% CI, 11.7-13.1) for Asian participants, 19.4 (95% CI, 19.2-19.6) for Black participants, 20.7 (95% CI, 20.1-21.3) for Hispanic participants, and 11.5 (95% CI, 11.4-11.6) for White participants. Compared with White participants, the fully adjusted hazard ratios were 1.05 (95% CI, 0.98-1.13) for American Indian or Alaska Native participants, 1.20 (95% CI, 1.13-1.28) for Asian participants, 1.54 (95% CI, 1.51-1.57) for Black participants, and 1.92 (95% CI, 1.82-2.02) for Hispanic participants. Across most US regions, age-adjusted dementia incidence rates were highest for Black and Hispanic participants, with rates similar among American Indian or Alaska Native, Asian, and White participants.CONCLUSIONS AND RELEVANCE Among older adults who received care at VHA medical centers, there were significant differences in dementia incidence based on race and ethnicity. Further research is needed to understand the mechanisms responsible for these differences.

Dr. Kodishala et al reply

“…The results presented in the study 2 are already adjusted for age, sex, and calendar year of RA incidence. Although education and race have been previously associated with the risk of dementia in the general population, 3,4 these risk factors had no statistically significant association with dementia in our study. 2 We have acknowledged as a limitation that our population-based study includes predominantly White individuals, consistent with the racial distribution of the underlying population.…”

Burden of neurological diseases in Asia from 1990 to 2019: a systematic analysis using the Global Burden of Disease Study data

“… 9 The exact cause of these differences is unknown, but nutrition, physical activity, genetic influence and access to healthcare may have affected the results. 34 35 As for dementia, there seems to be no significant improvement compared with 1990, which could be attributed to the lack of development of new powerful preventive and therapeutic drugs. 36 37 Considering the current global change into an ageing society, medical research and social support for dementia are essential.…”

“…In the 2019 GBD report, DALYs of Alzheimer’s disease and other dementias were slightly increased from 1990 9. The exact cause of these differences is unknown, but nutrition, physical activity, genetic influence and access to healthcare may have affected the results 34 35. As for dementia, there seems to be no significant improvement compared with 1990, which could be attributed to the lack of development of new powerful preventive and therapeutic drugs 36 37.…”

Utilizing Electronic Medical Records Identifies Similarities and Differences in Alzheimer’s Disease Comorbidities Between Racialized Populations

“…Related to intraracial heterogeneity, we also did not study the role of intersectional identities, such as sex, gender, LGBTQIA+ identity, and disability status, and their impact on health outcomes within racialized populations 35 . Also, Indigenous patients were not included due to low numbers, and while some studies have included this population to determine their rate of dementia incidence and survival after diagnosis, methods robust to smaller sample size will likely need to be routinely leveraged in order to systematically include these patients 13,35,47 . Additionally, beyond intraracial heterogeneity, over 10% of people identify as multiracial in the U.S., suggesting that studying populations stratified by R&E categories may result in the exclusion of a substantial number of individuals who identify with more than one category 48 .…”