ST. LOUIS—Use of metformin for Type 2 diabetes significantly reduces the risk of dementia among African American male veterans older than 50, according to a large observational cohort study.

The study published in the Annals of Family Medicine included data from 73,500 patients who received care through the VHA from 2000-2015; participants were diabetes- and dementia-free at baseline but subsequently developed Type 2 diabetes and began treatment with either metformin or sulfonylurea.

“African American patients are more likely to experience cognitive decline after Type 2 diabetes mellitus onset than white patients,” wrote the Saint Louis University School of Medicine-led authors. “Metformin use has been associated with a lower risk of dementia compared with sulfonylureas. Evidence for whether this association differs by race is sparse.”

Also participating in the study were the Harry S. Truman VAMC in Columbia, MO, and the Sant Louis VAMC.

Researchers reported that, after controlling for confounding, among patients aged 50 and older, metformin vs. sulfonylurea use was associated with a significantly lower risk of dementia in African American patients (hazard ratio [HR] = 0.73; 95% CI, 0.6-0.89) but not white patients (HR = 0.96; 95% CI, 0.9-1.03).

The study determined that the strongest magnitude of association between metformin and dementia was observed among African American patients aged 50 to 64 years (HR = 0.6; 95% CI, 0.45-0.81).

In addition, among veterans aged 65 to 74 years, metformin was significantly associated with lower risk of dementia in both races, although the drug was not associated with dementia in patients 74 and older.

“Metformin vs. sulfonylurea initiation was associated with a substantially lower risk of dementia among younger African American patients,” study authors concluded. “These results may point to a novel approach for reducing the risk of dementia in African Americans with Type 2 diabetes mellitus.”

  1. Scherrer JF, Morley JE, Salas J, Floyd JS, Farr SA, Dublin S. Association Between Metformin Initiation and Incident Dementia Among African American and White Veterans Health Administration Patients. Ann Fam Med. 2019Jul;17(4):352-362. doi: 10.1370/afm.2415. PubMed PMID: 31285213.