Evaluation of vitamin B12 level in middle-aged obese women with metabolic and nonmetabolic syndrome: case-control study

Aim: To investigate the correlation between vitamin B12 and body mass index (BMI) along with insulin resistance (IR) in middle-aged obese women. Materials and methods: The study was designed as a case-control study. The study group included middle-aged obese women and the control group included aged-matched lean women. Weight, height, and hip and waist circumferences were measured. Biochemical parameters such as fasting and postprandial glucose, vitamin B12 and folic acid levels, and lipid profiles were assayed. Results: Enrolled in the study were 116 middle-aged obese and 103 aged-matched healthy lean women. The vitamin B12 level of the obese women was significantly lower than that of the lean women (244.1 +/- 131.5 pg/mL vs. 336.2 +/- 163.1 pg/mL, P = 0.002). However, there was no significant difference in folic acid levels between the groups (P > 0.05). The vitamin B12 level was similar in the obese women with metabolic syndrome and those without (245.1 +/- 145.3 pg/mL vs. 241.2 +/- 96.5 pg/mL, P > 0.05), but the level in the control group was significantly higher than that of patients with obesity and metabolic syndrome (P = 0.010 and P = 0.020, respectively). Vitamin B12 levels correlated with BMI (r = -0.259, P = 0.003) but not with IR (r = -0.053, P > 0.05). Conclusion: The vitamin B12 concentration was low in obese patients and this level negatively correlated with BMI, but not with homeostasis model assessment-estimated IR (HOMA-IR).