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Long-term metformin usage and cognitive function among older adults with diabetes

Ng TP, Feng L, Yap KB, Lee TS, Tan CH, Winblad B

Journal of Alzheimer's disease : JAD, 2014

204 participants

Abstract

Evidence strongly supports the important role of insulin resistance in cognitive decline and dementia and suggests that insulin sensitizers may protect against cognitive decline in diabetic and pre-diabetic individuals. Inconclusive results have been reported in clinical trials of rosiglitazone, an insulin sensitizer that also increases cardiovascular mortality risks. No study has yet reported a protective cognitive effect of metformin, an insulin-sensitizing biguanide widely used in diabetic patients. We studied 365 older persons aged 55 and over in the population-based Singapore Longitudinal Aging Study with diabetes who were followed up over 4 years. The odds ratios (OR) of association of metformin use (n = 204) versus non-use (n = 161) with cognitive impairment (Mini-Mental State Exam ≤ 23), and by duration: up to 6 years (n = 114) and more than 6 years (n = 90) were evaluated in cross-sectional and longitudinal multivariate analyses. Controlling for age, education, diabetes duration, fasting blood glucose, vascular and non-vascular risk factors, metformin use showed a significant inverse association with cognitive impairment in longitudinal analysis (OR = 0.49, 95% CI 0.25-0.95). Metformin use showed significant linear trends of association across duration of use in cross-sectional and longitudinal analyses (p = 0.018 and p = 0.002, respectively), with use for more than 6 years significantly associated with lowest risk of cognitive impairment in both cross-sectional…

How strong is the evidence?

Evidence Hub reads this as a cross-sectional, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 204 participants or records.

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