Vitamin D and Bladder Cancer Risk: An Umbrella Review and Second Order Meta-Analysis.
Bladder cancer is a common malignancy with a high recurrence rate, posing a significant public health burden. Beyond its role in bone health, vitamin D has been suggested to influence cancer risk, including bladder cancer.
To evaluate the association between serum vitamin D levels, dietary intake, and supplementation with bladder cancer risk.
This umbrella review included systematic reviews and meta-analyses from multiple databases, focusing on serum levels or intake of vitamin D and bladder cancer risk. Study quality was assessed using the JBI Critical Appraisal Tool. The Corrected Covered Area showed a 15.5% overlap. Considerable heterogeneity in study design, populations, and vitamin D assessment was noted. Two second-order meta-analyses were conducted for quantitative synthesis.
Eight studies met the inclusion criteria. Adequate serum vitamin D was generally defined as levels ≥ 30 nmol/L. Low serum vitamin D was significantly associated with increased bladder cancer risk (RR = 1.32; 95% CI: [1.27, 1.38]). Higher serum levels were linked to a non-significant risk reduction (RR = 0.86; 95% CI: [0.63, 1.16]). Evidence on dietary intake was inconsistent, with some analyses suggesting a modest protective effect, particularly when combined with specific dietary patterns.
Low serum vitamin D is consistently associated with increased bladder cancer risk, while maintaining levels above 30 nmol/L may provide some protection. Evidence on dietary intake and supplementation remains inconclusive. Future studies should adopt standardized methods for vitamin D measurement, explore the role of free versus total vitamin D, and clarify population-specific differences to better define vitamin D's role in bladder cancer prevention.
To evaluate the association between serum vitamin D levels, dietary intake, and supplementation with bladder cancer risk.
This umbrella review included systematic reviews and meta-analyses from multiple databases, focusing on serum levels or intake of vitamin D and bladder cancer risk. Study quality was assessed using the JBI Critical Appraisal Tool. The Corrected Covered Area showed a 15.5% overlap. Considerable heterogeneity in study design, populations, and vitamin D assessment was noted. Two second-order meta-analyses were conducted for quantitative synthesis.
Eight studies met the inclusion criteria. Adequate serum vitamin D was generally defined as levels ≥ 30 nmol/L. Low serum vitamin D was significantly associated with increased bladder cancer risk (RR = 1.32; 95% CI: [1.27, 1.38]). Higher serum levels were linked to a non-significant risk reduction (RR = 0.86; 95% CI: [0.63, 1.16]). Evidence on dietary intake was inconsistent, with some analyses suggesting a modest protective effect, particularly when combined with specific dietary patterns.
Low serum vitamin D is consistently associated with increased bladder cancer risk, while maintaining levels above 30 nmol/L may provide some protection. Evidence on dietary intake and supplementation remains inconclusive. Future studies should adopt standardized methods for vitamin D measurement, explore the role of free versus total vitamin D, and clarify population-specific differences to better define vitamin D's role in bladder cancer prevention.
Authors
Mancin Mancin, Ferrara Ferrara, Palomares Palomares, Matteucci Matteucci, Santagostino Santagostino, Ferrari Ferrari, Parozzi Parozzi, Petrelli Petrelli, Hurle Hurle, Sguanci Sguanci, Cangelosi Cangelosi
View on Pubmed