Circulating concentrations of B group vitamins and urothelial cell carcinoma.

B‐group vitamins, as components of the one carbon metabolism pathway, are involved in DNA synthesis, repair and methylation. Our aim was to investigate associations between circulating plasma levels of B vitamins and urothelial cell carcinoma (UCC). We conducted a nested case–control study of UCC within the Melbourne Collaborative Cohort Study. B vitamins were measured in pre‐diagnostic plasma samples. Conditional logistic regression was used to estimate odds ratios (OR) for UCC risk associated with circulating B vitamins in 363 matched cases and controls. In a case‐only analysis (N = 390), hazard ratios (HR) for overall survival associated with plasma B vitamins were estimated using Cox regression. There were no strong associations between UCC risk and pre‐diagnostic levels of plasma B vitamins. No heterogeneity in UCC risk was observed by subtype (invasive or superficial), sex, smoking status or alcohol intake. There was no heterogeneity by country of birth for most B vitamins, except for folate (p‐homogeneity = 0.03). In UCC cases, there were no strong associations between plasma B vitamins and overall survival. We found no associations between pre‐diagnostic plasma concentrations of B‐group vitamins and UCC risk or survival. What's new? B vitamins are involved in DNA synthesis, repair, and methylation, and therefore they might affect cancer risk. While they appear to be protective against some cancers, data on the effect of B‐vitamins on bladder cancer have been inconsistent. In this prospective study, the authors examined levels of circulating B vitamins in patients with urothelial‐cell carcinoma (UCC) and matched controls. However, they found no association between pre‐diagnostic concentrations of B vitamins and UCC risk or survival. [ABSTRACT FROM AUTHOR]