Researchers suggest improving people's blood level of vitamin D could be an important tool for preventing cancer, after their study found that the risk of developing the disease rises as vitamin D levels fall.

In the journal PLOS One, researchers from the University of California-San Diego (UCSD) School of Medicine report how they analyzed the link between vitamin D and cancer to determine what blood level of vitamin D was required to effectively reduce cancer risk.

The study included all invasive cancers, excluding skin cancer.