Taking supplements to overcome a vitamin D deficiency may cut the risk of dying by more than half compared to people who remain deficient. This finding comes from a University of Kansas analysis of data on more than 10,000 patients. The researchers first found that 70 percent of patients in the population they studied were deficient in “D” and were three times more likely to die of any cause than those whose vitamin D levels were normal. The risks of death dropped by more than half after the deficiencies were corrected with supplements.