Bladder Cancer is Associated with Low Plasma 25-hydroxyvitamin D Concentrations in Tunisian Population

abstract

Little evidence suggests an impact of vitamin D on bladder cancer risk in Caucasians. This study aimed to investigate association of plasma 25-hydroxyvitamin D (25-OHD) with urothelial bladder cancer (UBC) risk in Tunisians. A case-control study included 250 patients with UBC and 250 healthy controls. Plasma 25-OHD was assessed by a competitive chemiluminescence immunoassay. Vitamin D deficiency and insufficiency were defined as 25-OHD <30 nmol/L and 30 to 49.99 nmol/L, respectively. Logistic regression models adjusting for gender, age, smoking status, duration of smoking, occupational exposure, and season were applied. Vitamin D deficiency (50.4% vs. 34.8%; P < 0.001) and insufficiency (40.4% vs. 26.8%; P < 0.001) were more frequent in patients than controls. Multivariate analysis showed that UBC is associated with vitamin D deficiency [odd-ratio (95% confidence interval), 3.71 (1.76–7.80); P = 0.001] and vitamin D insufficiency [2.65 (1.40–5.01); P = 0.003]. Other predictors of UBC were female gender, tobacco use, smoking duration, and occupational exposure. Plasma 25-OHD concentrations are low in Tunisian patients with UBC. These findings support experimental and epidemiological evidence of protective role of vitamin D against UBC but could not ascertain causal relationship. Further prospective studies and clinical trials are warranted to check causality.

Additional information

Funding

The study was supported by Funds of Research Unit “05/UR 08-08” and Research Laboratory LR99ES11, Ministry of Higher Education and Scientific Research of Tunisia. The authors thank the members of Department of Urology staff and study participants for their contribution.