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The association between long-term metformin use in type 2 diabetes mellitus (T2DM) and low vitamin B12 levels has been proven and screening for the same is recommended by American Diabetes Association (ADA) guidelines. The potential of the deficiency to cause or worsen diabetic peripheral neuropathy (DPN) in T2DM patients has been investigated in previous studies. However, the prevalence estimates of vitamin B12 deficiency in T2DM patients treated with long term metformin and having established DPN is lacking in our country. The aim of our study was to estimate the prevalence of vitamin B12 deficiency in T2DM patients with DPN on metformin and find out the risk factors for vitamin B12 deficiency in these patients.


This cross-sectional study was conducted in the department of endocrinology in a tertiary care hospital on T2DM patients with DPN on long term metformin therapy. Vitamin B12 levels were estimated in all the subjects and the prevalence and risk factors for Vitamin B12 deficiency were assessed.


The prevalence of vitamin B12 deficiency in our patients was 32%. Based on the correlation estimates, none of the factors studied were significantly associated with variations in Vitamin B12 levels.


Our study found that a third of metformin treated T2DM patients with peripheral neuropathy had vitamin B12 deficiency with no specific clinical predictor for the same. We thereby recommend screening for vitamin B12 deficiency in T2DM patients on long-term metformin and with established DPN.

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Ajay Hanumanthu

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Vitamin B12 deficiency Distal Peripheral Neuropathy Type 2 Diabetes Mellitus Metformin

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



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