Vitamin D Deficiency and Increased Risk of Bladder Carcinoma: A Meta-Analysis.

Background/Aims: Vitamin D status in relation to bladder carcinoma risk was still inconsistent. This study was carried out to evaluate the relationship between vitamin D status and bladder carcinoma risk through a meta-analysis approach. Methods: Pubmed, Web of Science, CNKI, and Embase were searched systemically to find eligible studies from the earliest available date to April 16, 2015. The search terms “vitamin D”, “25-hydroxyvitamin D”, “bladder cancer” or “bladder carcinoma” were used to retrieve relevant studies. The exposure of interest was intake of vitamin D or serum vitamin D levels, and the outcome of interest was bladder carcinoma incidence or mortality. The pooled risk ratio (RR) values and their 95%CIs were calculated through meta-analysis. Results: Seven studies with a total of 62,141 participants met the inclusion criteria and were finally included into the meta-analysis. There was no heterogeneity among those included studies (I2 = 0%, P = 0.53). The pooled RR of bladder carcinoma for the lowest category versus the highest category of vitamin D was 1.34 (95% CI 1.17-1.53, P Conclusion: Vitamin D deficiency is associated with increased risk of bladder carcinoma in present study.