Hektoen HH, Gislefoss RE, Stenehjem JS, et al. - Findings indicate that vitamin D deficiency has a more critical role in an early stage of urothelial bladder cancer (BC).

• From 378 BC patients within the population-based Janus Cohort, prediagnostic serum were used.

• Hzard ratios (HRs), with 95% confidence intervals (CIs), were estimated.

• An elevated risk of BC-specific mortality (HR 1.87, 95% CI 1.10– 3.20) was observed in relation to the presence of 25-hydroxyvitamin D (25(OH)D) deficiency (< 50 nmol/L) prior to a BC diagnosis, vs insufficient levels (50– 74 nmol/L).

• The findings were evident among non-muscle invasive BC cases only.

• There was no link between 25(OH)D levels and all-cause mortality in cancer-free controls.