Metformin Use Tied to Lower Risk for Dementia, Death in Adults With Overweight, Obesity

TUESDAY, Aug. 12, 2025 (HealthDay News) — Metformin use is associated with lower risks for dementia and all-cause mortality across body mass index (BMI) groups in patients with overweight or obesity, according to a study published online Aug. 6 in Diabetes, Obesity and Metabolism.

Yu-Liang Lin, M.D., from Taipei Medical University in Taiwan, and colleagues conducted a multicenter cohort study to investigate whether metformin use was associated with a lower long-term incidence of dementia and all-cause mortality in patients with overweight or obesity. The analysis included electronic health record data from the TriNetX network, consisting of 132,920 patients with a BMI of 25 to 29.9 kg/m², 142,723 with a BMI 30 to 34.9 kg/m², 94,402 with a BMI of 35 to 39.9 kg/m², and 82,732 with a BMI >40 kg/m². Propensity score matching was used to compare adults in each BMI group prescribed metformin to matched controls who were not prescribed metformin.

The researchers found that during 10 years of follow-up, metformin users showed significantly lower risks for both dementia and all-cause mortality versus controls. Risk for dementia was lower across each BMI group (hazard ratios [HRs], 0.875, 0.917, 0.878, and 0.891, respectively). A similar trend was seen for the risk for all-cause mortality (HRs, 0.719, 0.727, 0.717, and 0.743, respectively).

“In this large, multicenter cohort study, metformin use was associated with reduced risks of dementia and all-cause mortality in obese patients. The protective effect was observed across all BMI groups, with variations noted by population,” the authors write. “These findings support the potential of metformin in lowering dementia risk in patients with obesity. Further studies are needed to explore the underlying mechanisms.”

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