Table 9: Necessity of vitamin B12 supplementation during the follow-up period.

BMI
35–39.9 kg/m²40–49.9 kg/m²50–59.9 kg/m²≥ 60 kg/m²Total
Vitamin B12n%n%n%n%n%

After OP00.000.000.015.611.2
After 3 months116.7417.4514.315.61113.4
After 6 months00.014.3411.415.667.3
After 12 months00.014.300.015.622.4
After 18 months00.000.000.000.000.0
After 24 months00.000.000.000.000.0
After 2nd OP116.728.71028.6527.81822.0

Total233.3834.81954.3950.03846.3