Background/aim: Many studies have investigated risk factors other than antibiotic resistance linked to Helicobacter pylori (H. pylori) eradication failure. The aim of this study was to study the effect of serum levels of 25-hydroxy-vitamin D (25[OH]D) on eradication rates of H. pylori infection.

Methods: This study included 150 patients diagnosed with H. pylori gastritis using magnifying narrow-band imaging endoscopy supported by stool antigen test. Serum 25-OH vitamin D levels were measured via the Enzyme-Linked Immune Sorbent assay (ELISA) method before starting eradication therapy of H. pylori infection. All patients were treated with clarithromycin-based triple therapy for 14 days. H. pylori eradication was determined via a stool antigen test performed 4 weeks after the end of therapy. According to the serum level of 25-OH vitamin D levels, the patients were divided into two groups: group I (sufficient) had a vitamin D level of ≥20 ng/mL, while group II (deficient) had a vitamin D level of <20 ng/mL.

Results: Our results revealed that eradication was successful in 105 (70%) patients and failed in 45 (30%) patients. The mean 25[OH]D level was significantly lower in the eradication failure group compared to the successful treatment group (14.7 ± 4.5 vs 27.41 ± 7.1; P < 0.001). Furthermore, there were significantly more patients with deficient 25[OH]D levels in the failed treatment group, 30 (66.6%), compared to the successful group, 10 (9.5%) (P < 0.001).

Conclusions: Our results demonstrated that 25-OH vitamin D deficiency may be considered a risk factor related to eradication failure of H. pylori infection. In addition, a further randomized trial to evaluate the effect of vitamin D supplementation in H. pylori eradication is mandatory.