Low levels of vitamin D have been linked to a greater risk of bladder cancer, according to a new study, adding to the body of evidence suggesting that a lack of vitamin D is detrimental to health.
Researchers from the University of Warwick, led by Dr Rosemary Bland, set out to find out more about how synthesis of vitamin D might affect immune responses in specific tissues.
They carried out a systematic review of seven studies to investigate the link between vitamin D and bladder cancer. The number of participants per study ranged from 112 to 1,125. Some of the studies measured vitamin D levels before diagnosis, some during, and some at the follow-up stage.
Five out of the seven studies found that the risk of bladder cancer goes up when vitamin D levels are low. Higher vitamin D levels also correlated with better survival and outcomes in people with bladder cancer.
The team also examined the cells that line the bladder, known as transitional epithelial cells. They found that these cells can activate and respond to vitamin D, and that they can synthesise enough vitamin D to trigger a local immune response. By recognising abnormal cells before they develop further, the immune system may be able to use this information to prevent cancer.
The researchers conclude that bladder cancer risk correlates with low vitamin D levels. Dr Bland suggests that if this is confirmed, administering supplementary vitamin D could be a safe and economical means of prevention.
"More clinical studies are required to test this association, but our work suggests that low levels of vitamin D in the blood may prevent the cells within the bladder from stimulating an adequate response to abnormal cells. As vitamin D is cheap and safe, its potential use in cancer prevention is exciting and could potentially impact on the lives of many people," Dr Bland said.
The results of the study were presented at the Society for Endocrinology conference in the United Kingdom.