203 ORIGINAL ARTICLE Association of vitamin B12 with obesity, overweight, insulin resistance and metabolic syndrome, and body fat composition; primary care-based study Davut Baltaci 1 , Ali Kutlucan 2 , Yasemin Turker 3 , Aylin Yilmaz 1 , Serkan Karacam 1 , Harun Deler 1 , Taner Ucgun 4 , Ismail Hamdi Kara 1 1 Department of Family Medicine, 2 Department of Internal Medicine, 3 Family Medicine Office, 4 Department of Biochemistry; Duzce Univer- sity, School of Medicine, Duzce, Turkey Corresponding author: Davut Baltaci Department of Family Medicine, School of Medicine, Duzce University Konuralp, Duzce, 81620, Turkey Phone: +90 380 54 213 90; Fax: +90 380 54 213 87; E-mail: davutbaltaci@hotmail.com Original submission: 24 December 2012; Revised submission: 03 January 2013; Accepted: 24 January 2013. ABSTRACT Aim To investigate correlation of vitamin B12 with obesity insulin resistance, metabolic syndrome. Methods The cross-sectional and primary care-based study was carried out. Anthropometric, blood pressure measurements and bi- oelectric impedance analysis (BIA) were recorded. Vitamin B12, folic acid, hemogram, insulin, ferritin, iron, total iron binding capacity and other biochemical tests were assayed. The subjects were grouped as obesity, overweight, control, metabolic syndro- me (MetS) and insulin resistance (IR). Correlation of vitamin B12 with body mass index (BMI), IR, age, and BIA was evaluated. Results The study enrolled 976 patients (obesity: 414, overweight: 212, and control: 351). The mean age in groups of obesity, overwe- ight and control were 35.9 ± 8.7, 28.9 ± 6.3 and 33.1 ± 8.7, res- pectively (p = 0.142). Vitamin B12 level was significantly lower in patients with obesity and overweight than healthy individuals (178.9 ± 25.2; 219.8 ± 78.5, and 328.5 ± 120.5, p < 0.001, respecti- vely). Vitamin B12 level was lower in patients with MetS (+/-) and IR (+/-), but insignificant (p = 0.075 and 0.058, respectively). Si- gnificant and negative correlation was observed between vitamin B12 and BMI (r =-0.221, p=0.001). No significant difference was observed between obese male and female patients (247.8 ± 89.1 versus 235.5 ± 89.3 pg/mL, respectively, p=0.090). Conclusion Low Vitamin B12 level was associated with obesity and overweight, but not with insulin resistance, metabolic syndro- me and gender. Vitamin B12 was negatively correlated only with body mass index. Keywords: vitamin B12, obesity, insulin resistance, bioelectric impedance analysis Med Glas (Zenica) 2013; 10(2):203-210