In people with low blood levels of vitamin D, boosting them with supplements more than halved a person's risk of dying from any cause compared to someone who remained deficient, in a large new study.
Analyzing data on more than 10,000 patients, University of Kansas researchers found that 70 percent were deficient in vitamin D and they were at significantly higher risk for a variety of heart diseases.
D-deficiency also nearly doubled a person's likelihood of dying, whereas correcting the deficiency with supplements lowered their risk of death by 60 percent.
"We expected to see that there was a relationship between heart disease and vitamin D deficiency; we were surprised at how strong it was," Dr. James L. Vacek, a professor of cardiology at the University of Kansas Hospital and Medical Center, told Reuters Health.
"It was so much more profound than we expected."
Vitamin D deficiency has been linked to a range of illnesses, but few studies have demonstrated the reverse -- that supplements could prevent those outcomes.