Evaluation of Serum Vitamin D3 Levels and Factors Associated with Chronic Hepatitis B: A Case-Control Study

Introduction: Chronic hepatitis B (CHB) is caused by hepatitis B virus infection. It has been shown that vitamin D3 has very important biological effects in the immune system and host response to viral infection. This study aimed to identify potential risk factors of vitamin D deficiency among CHB patients in Birjand, Iran. Materials and Methods: In this case-control study, there were 292 patients with CHB and 304 healthy subjects as a control group in the outpatient clinic of the Infectious Diseases Department from January, 2017 to December, 2018. Of all the subjects, 62.7% of the control and 48.1% of the case groups were male. We quantified the levels of total vitamin D3 in their serum samples. We employed t- and chi-square tests along with logistic regression to determine the association between the variables of interest and vitamin D3 deficiency related to CHB (p<0.05). Results:  The mean age and vitamin D3 levels of the case group were 39.9 ±13.3 years and 20.76 ±15.53ng/ml, and for the control group 43 ±13.3 years and 19.07 ±12.41 ng/ml. No significant association between vitamin D3 deficiency and CHB risk factors was found (p>0.05). The prevalence of vitamin D3 inadequacy was high in both HBV patients (63%) and in the healthy group (52.9%). The frequency distribution for the vitamin D3 serum level was significantly different in the two groups (p=0.001). Conclusions: According to the results, a high risk of vitamin D3 deficiency related to CHB was not found among CHB patients in Birjand, in contrast to previous literature. Possible reasons for these findings were discussed, although future comprehensive studies are needed to clarify underlying mechanisms and real association.