Objectives: Veterans of the armed forces, like most population groups, have a high prevalence of vitamin D deficiency, which may be associated with adverse outcomes in several types of cancer. Ultraviolet irradiation is inversely linked with the risk of bladder cancer, presumably through enhanced vitamin D synthesis. We hypothesized that variations in vitamin D status and monitoring predict adverse outcomes in bladder cancer among veterans.
Methods: A retrospective analysis of data in the Veterans Integrated Service Network-9 (southeastern United States) was performed for patients diagnosed between October 1, 1999 and February 29, 2008. Age, tobacco exposure, body mass index, and latitude and seasonality of sampling were included as variables in addition to serum vitamin 25(OH)D levels.
Results: Monitoring of vitamin D and vitamin D levels and status were closely linked to survival in bladder cancer. Both the chances of survival and longevity improved with enhanced vitamin D status and monitoring. Veterans with bladder cancer had better outcomes if the initial vitamin D level was higher and had more monitoring of the vitamin. Initial vitamin D levels were more strongly related to outcomes than follow-up levels. The link between vitamin D and outcomes remained after adjusting for background variables such as age, body mass index, latitude, seasonality, and tobacco exposure.
Conclusions: Findings suggest that adequate vitamin D levels early in the course of the disease provide the best opportunity to improve outcomes. Ensuring that veterans with bladder cancer have adequate vitamin D reserves with appropriate monitoring may play a role in improving outcomes in bladder cancer.