[The investigation of the positive rate of intrinsic factor antibody and deficiency rate of vitamin B(12) in normal physical examination population]

Objective: To explore the positive rate of intrinsic factor antibody (IFAb) and level of vitamin B(12) (VitB(12)) in normal physical examination population and the possible relation between IFAb, VitB12 and sex, age, number of RBC, HGB and MCV. Methods: A total of 1 427 people who came to Peking Union Medical Colleague Hospital (PUMCH) for physical examination were enrolled. There were 758 males with average age of (52.5±14.5) years-old and 669 females with average age of (50.3±14.3) year-old. Beckman DxI800 automatic biochemical-immune analyzer and corollary reagents were used to analyze the level of serum IFAb and VitB(12). The results in different sex, age were documented and their correlation with the value of whole blood cell count was tested later on. Results: Among the 1 427 normal subjects, 66 (4.63%) were positive for IFAb. The positive rate for IFAb in the population≥40 years-old was higher than those<40 years-old (5.66% vs 1.48%, χ(2)=7.46, P=0.006). The deficiency rate of VitB(12) in the population<40 years-old, 40-59 years-old and ≥60 years-old was 2.22%, 2.51% and 5.50%, respectively (χ(2)=8.55, P=0.014). There were no difference between people with different sex in the positive rate of IFAb (5.15% for males and 4.04% for females, χ(2)=0.99, P=0.320) or in the deficiency rate of VitB(1)2 (3.83% for males and 2.69% for females, χ(2)=1.44, P=0.230). The results of multiple linear regression showed that HGB level of IFAb positive subjects was 3.05 g/L lower on average than those of IFAb negative, but IFAb had no effect on both RBC and MCV. There was no correlation between VitB(1)2 deficiency and HGB, RBC and MCV. Conclusion: The positive rate of IFAb and deficiency rate of VitB(1)2 increase as age increases. But the presence of VitB(12) deficiency is later than the positive findings of IFAb. IFAb showed some effects on the level of HGB, which may compensate the limitations of VitB(12) detection to some extent. It is necessary to check the IFAb and level of VitB(12) in people with middle or old ages.