Profiling immuno-metabolic mediators of vitamin B.sub.12 deficiency among metformin-treated type 2 diabetic patients in Ghana

• Published in: PloS one 2021-03, Vol.16 (3), p.e0249325
• Main Authors: Sakyi, Samuel Asamoah, Laing, Edwin Ferguson, Mantey, Richard, Kwarteng, Alexander, Owiredu, Eddie-Williams, Dadzie, Richard Ephraim, Amoani, Benjamin, Opoku, Stephen, Afranie, Bright Oppong, Boakye, Daniel
• Format: Article
• Language: English
• Subjects: Complications and side effects; Diagnosis; Dosage and administration; Drug therapy; Metformin; Risk factors; Type 2 diabetes; Vitamin B12 deficiency
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0249325

The association between prolong metformin usage and B12 deficiency has been documented. However, the prevalence estimates of metformin-induced vitamin B12 deficiency showed substantial disparity among studies due to varied study definitions of vitamin B12 deficiency. Metformin blocks the calcium dependent absorption of the vitamin B12-Intrinsic Factor complex at the terminal ileum. Lack of intrinsic factor due to the presence of auto-antibodies to parietal cells (IFA) could lead to vitamin B12 deficiency and subsequently cause peripheral neuropathy. We investigated the prevalence of vitamin B12 deficiency using more sensitive, combined markers of vitamin B12 status (4cB12) and the immuno-biochemical mediators of vitamin B12 deficiency. In this observational study, 200 consecutive consenting metformin-treated T2DM patients, aged 35 and above, attending the diabetic clinic at KATH were recruited. Vitamin B.sub.12 deficiency was classified based on the Fedosov age-normalized wellness quotient. Anthropometric measurement was taken as well as blood samples for immunological and biochemical mediators. Peripheral neuropathy was assessed using the Michigan Neuropathy Screening Instrument (MNSI). Statistical analysis was performed using the R Language for Statistical Computing. Using the combined indicator (4cB.sub.12 ), the prevalence of metformin induced vitamin B12 deficiency was 40.5% whilst the prevalence of MNSI-Q and MNSI-PE diabetic neuropathy was 32.5% and 6.5% respectively. Participants with vitamin B.sub.12 deficiency had significantly higher levels of IFA, GPA, TNF-[alpha], TC, LDL and albumin compared to those with normal vitamin B.sub.12 levels (p < 0.05). Correlation analysis revealed a statistically significant negative association between 4cB.sub.12 and the immunological markers [IFA (rs = -0.301, p