Objective: There are studies which determine the connection between deficiency or surplus of serum vitamin D, folic acid and B12, ashyma and wheezing attacks. This study aimed to determine whether or not there was any significant connection between serum vitamin D, folic acid and B12 levels and recurrent wheezing attacks.

Materials and Methods: One hundred and seven children aged 0-3 years who presented with a history of at least 3 episodes of wheezing and no secondary causes, and 86 healthy children in similar age group were included in this study. A questionnaire was applied which examined the sociodemographic characteristics and risk factors of the chidren and their families. Serum 25 OH D3, folic acid and B12 levels of the patients and the control group were measured.

Results: The two groups were similar in respect of age or gender. The mean serum 25 OH D3 level was 26.64 ± 11.01 ng/mL in the patient group and 33.98 ± 10 ng/mL in the control group (p< 0.001). Vitamin D deficiency was found to be 45 (42%) children in the patient group, and 15 (17.4%) children in the control group (p= 0.0002). No statistically significant difference was seen between the groups in B12 or folic acid levels (p= 0.78, p= 0.60, respectively).

Conclusion: The vitamin D intake and the serum vitamin D level were lower in the children with recurrent wheezing compared to the control group which indicate that deficiency of vitamin D may have a role in the etiology of recurrent attacks of wheezing. This evidence proved that the vitamin D intake, and if needed, the serum level need to be controlled. No relationship was determned between the deficiency of B12 and folic acid and recurrent wheezing attacks. There is a need for further studies on the subject of B12 and folic acid.