PREVALENCE OF VITAMIN B12 DEFICIENCY AND ITS ASSOCIATION WITH PERIPHERAL NEUROPATHY IN PATIENTS WITH TYPE 2 DIABETES MELLITUS

Abstract

Background: Vitamin B12 deficiency is an underrecognized complication among patients with type 2 diabetes mellitus (T2DM), particularly in those on long-term metformin therapy. Peripheral neuropathy is one of the most disabling complications of diabetes, and its coexistence with vitamin B12 deficiency may worsen neurological outcomes.

Objectives: To determine the prevalence of vitamin B12 deficiency and to assess its association with peripheral neuropathy in patients with T2DM.

Study design & Setting: A cross-sectional study was conducted at the Department of Medicine, Sheikh Zayed Hospital Lahore over six months from January to June 2025.

Methodology: A total of 120 patients with T2DM were enrolled using non-probability consecutive sampling. Serum vitamin B12 levels were measured and categorized as normal (>300 pg/mL), borderline (200–300 pg/mL), or deficient (<200 pg/mL). Peripheral neuropathy was assessed clinically using standard neurological examination. Demographic and clinical data, including age, gender, duration of diabetes, and HbA1c levels, were collected. Data were analyzed using SPSS version 25. Chi-square test was applied to assess associations, with p ≤ 0.05 considered statistically significant.

Results: The mean age of participants was 49.7 ± 12.1 years, with 55.8% males. Vitamin B12 deficiency was observed in 21.7% and borderline levels in 18.3% of patients. Peripheral neuropathy was detected in 32.5% of patients. A statistically significant association was found between low vitamin B12 levels (deficient + borderline) and peripheral neuropathy (p = 0.004), while no significant associations were observed with age, gender, duration of diabetes, or HbA1c levels.

Conclusion: Vitamin B12 deficiency is common in T2DM patients and is significantly associated with peripheral neuropathy. Routine screening and timely correction of vitamin B12 deficiency may reduce diabetes-related neurological complications.