A recent Taiwanese study suggests that long-term use of the popular diabetes medication Metformin may actually increase the risk of neurodegenerative disease in patients with type 2 diabetes mellitus. Their research contradicts the results of a recent large-scale study that suggested Metformin exerts a protective effect against the same diseases. Both studies were large scale longitudinal research projects. The Taiwan study followed 9,300 patients for up to 12 years and found the risk for Parkinson’s or Alzheimer’s more than doubled for those taking Metformin compared with those who did not. Medscape reported that researchers found that outcome risks increased progressively with higher dosage and longer duration of treatment, especially with use for more than 300 days. The US study consisted of 6,046 patients (>90% male) and were followed for a median of 5.25 years. In contrast to the Taiwan study, the US study showed that Metformin exposure for longer than two years resulted in a significant reduction in neurodegenerative disease. Interestingly, recent evidence suggests metformin may cause B12 deficiency, particularly in those who take it long-term.
Yi-Chun Kuan, et al. The 13th International Conference on Alzheimer’s and Parkinson’s Diseases. Vienna Austria March 29, 2017