Hispanic/Latino Ethnicity Associated with Diabetes, Cognitive Decline, & Impairment

Long-term diabetes may lead to signs of cognitive decline in Latino patients as early as middle age.

Representing one-fifth of the population, Latinos are the largest ethnic group in the United States, with the highest prevalence of diabetes and the earliest age of diabetes diagnosis of any ethnic group in the country. Additionally, mild cognitive impairment and dementia onset are present earlier in Latinos compared to other ethnicities. Nonetheless, very few studies have scrutinized cognitive decline and disorders among middle-aged Latinos (when the decline in cognition is thought to occur).  

Generally, the studies that have been conducted previously focused on older adults with cognitive aging and disorders. Most participants were over 75 years and researchers relied on self-reports or medical records for a diabetes diagnosis. Additionally, not many of these studies followed the American Diabetes Association diagnostic criteria for diabetes. Lastly, previous studies were not racially inclusive, mainly studying Caucasians, and did not survey diabetes, cognition, and mild cognitive impairment in other populations in which diabetes is significantly prevalent. The purpose of this study was to be inclusive primarily of the middle-aged and older Latino population, testing the relationship between diabetes, cognitive decline, and mild cognitive impairment to assess whether extensive diabetes exposure affects relationships between cognitive decline and mild cognitive impairment.  

This study utilized Latinos-Investigation of Neurocognitive Aging, a Hispanic Community Health Study/Study of Latinos ancillary study. The latter was a multisite, population-based, probability sampled, prospective cohort study of cardiovascular disease and diabetes among diverse Latinos. Using complex survey sampling procedures, researchers designed the study to yield representative data for diverse Latinos in four targeted areas in the United States: Bronx, NY; Chicago, IL; Miami, FL; and San Diego, CA. Participants were included in this trial if they completed two visits, had one neurocognitive test completed, and were > 50 years of age. Considering these criteria, 6,377 eligible participants agreed to be in this study.  

Descriptive statistics were used to characterize the target population overall and by diabetes status. The test differences in means for cognitive measures were described at visit one for each cognitive domain and global cognition. A survey-adjusted t-test was used to scrutinize crude and age and sex-adjusted mean difference between incident and prevalent diabetes, separately, compared to no diabetes. Additionally, each test was compared for the crude and adjusted cognitive scores for no diabetes with those for incident diabetes and prevalent diabetes. Finally, a sensitivity analysis was used to adjust the estimated models derived from the linear survey regression for cognitive change and the survey logistic regression model for mild cognitive impairment.  

Over a quarter of people with diabetes were recognized at the first visit, and one in ten participants met the criteria for incident diabetes. Diabetes at the first visit was associated with significant global cognitive decline, domain-specific cognitive decline, and a higher risk of mild cognitive impairment, but not at the second visit with incident diabetes. All are comparable with persons with no diabetes in age and sex-adjusted models. With this data was a p-value recognized of significance at <0.001. Additionally, almost half of the population met the hypertension criteria, with 3.5% reporting a prevalent stroke/TIA and 3.1% a myocardial infarction. Diabetes was more prevalent in the older age group (66 years) who were more likely to have hypertension and less than twelve years of education. This prevalent diabetes group had consistently lower scores on all considered cognitive tests.  

To conclude, researchers were able to quantify that diabetes is associated with cognitive decline and increased mild cognitive impairment prevalence among diverse Latinos, specifically in individuals with prevalent diabetes at the first visit. Therefore, researchers of this study propose that their findings indicate significant cognitive decline and mild cognitive impairment should be considered additional disease complications of diabetes among middle-aged and older Latinos. However, this study’s limitations are significant for the brief cognitive assessment performed and reliance on self-reported subjective cognitive decline and functional decline.  

Practice Pearls: 

• Latinos are associated with an increased risk of mild cognitive impairment due to the increased prevalence of type 2 diabetes. 
• This study showed the correlation between this ethnicity specifically and neurocognitive effects. 
• Limitations exist that question the validity of the reports of mild cognitive impairment.  

Reference for “Hispanic/Latino Ethnicity Associated with Diabetes, Cognitive Decline, & Impairment”:
González, H., Tarraf, W., González, K., Fornage, M., Zeng, D., Gallo, L., Talavera, G., Daviglus, M., Lipton, R., Kaplan, R., Ramos, A., Lamar, M., Cai, J., DeCarli, C. and Schneiderman, N., 2020. Diabetes, Cognitive Decline, and Mild Cognitive Impairment Among Diverse Hispanics/Latinos: Study of Latinos–Investigation of Neurocognitive Aging Results (HCHS/SOL). Diabetes Care, p.dc191676. 

Deonna Andrews, PharmD Candidate 2020 of Florida Agricultural & Mechanical University College of Pharmacy and Pharmaceutical Sciences