Introduction: Considering the link between vitamin A deficiency and disease activity in ulcerative colitis (UC) and also the association between dietary intake of vitamin A and gastrointestinal symptoms in these patients, this study aimed to investigate the effect of vitamin A supplementation on disease activity in patients with UC.
Method: In the present double-blind randomized controlled clinical trial, one hundred and fifty patients with Mayo score of 6-12 were randomly assigned to receive 25,000 IU/day vitamin A supplements or placebo for two months. The disease activity was calculated by the Mayo clinic score. Within groups and between groups comparisons were performed using paired sample t-test and one-way ANCOVA respectively. For measuring the treatment effect, the response ratio and number needed to treat (NNT) was calculated for the rate of clinical response and mucosal healing.
Results: One hundred and forty three patients completed the study. After two months of supplementation, significant decreases in Mayo clinic score (p < 0.001) and subscores (p < 0.001) was observed in the intervention group. There were significant differences between the two groups regarding Mayo clinic score and subscores after adjusting for age, sex, BMI, disease duration and baseline values (P < 0.05). Moreover, there were significant differences between two groups regarding clinical response ratio (P < 0.001) and mucosal healing ratio (P < 0.001). The NNT [95%CI] values for the clinical response was 3 [2-40] and for the mucosal healing was 5 [2.90-10.4].
Conclusion: Although according to the results, daily dose of 25,000 IU vitamin A had positive clinical and endoscopic effects, considering the limitations, further studies with longer duration and larger sample size and considering dietary intake are needed to confirm these preliminary results.
Keywords: Disease activity index; Endoscopy; Mayo clinic score; Mucosal healing; Ulcerative colitis; Vitamin A.
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