To achieve these levels, about half of the patients had to take higher-than-usual doses of vitamin D, about 5,000 IUs a day. (By comparison, the recommended daily amount of vitamin D supplementation is typically between 800 to 1,000 IUs.)
(Why vitamins A and E can cause harm in large doses.)
“The average time to get to a therapeutic threshold took about five months,” says Helen May, a researcher at the University of Utah, and one of the authors of the study.
Patients were followed for an average of four years. Since this was a high-risk population, there were a total of 107 major cardiac events reported during the course of the study, including heart failure hospitalizations, heart attacks, stroke, and death. Patients who received the vitamin D supplements experienced a 50 percent reduction in the risk of having a second heart attack, as well as an overall reduction in the risk of having a major cardiac event.
Looking ahead
TARGET-D is an important study, in that it has established that a high-risk population of patients can benefit from supplementing vitamin D to a target concentration of between 40 and 80 ng/mL. This study will need to be repeated in a larger sample of patients.
