Low vitamin D levels can give you cancer and increase your risk of death

vitamin D levels are typically measured in terms of blood serum levels of 25-hydroxy vitamin D (25(OH)D). Individuals with 25(OH)D levels lower than 50 nmol/L but higher than 30 nmol/L were found to be about 17 percent more likely to die early, while ...

http://www.naturalnews.com/039740_vitamin_D_deficiency_death_risk.html