'D' Good News for Stroke Patients
July 9, 2001 -- Stroke patients are two to four times more likely to break a hip than others are. And those who are elderly, immobile, and lacking in vitamin D are at even greater risk of hip fracture, according to a study reported in the July issue of Stroke. But there is help: Vitamin D supplements can protect these people.
Vitamin D deficiency is common in elderly people with disabilities, especially those who are housebound, bone disease expert Chad Deal, MD, tells WebMD. "These patients have little sun exposure and low intake of vitamin D-fortified foods, the two major sources of vitamin D," he says. Deal, who heads the Cleveland Clinic Foundation's Center for Osteoporosis and Metabolic Bone Disease in Ohio, was not involved with the study.
In this study, Japanese researcher Yoshihiro Sato, MD, of Hirosaki University School of Medicine, and fellow researchers studied stroke patients aged 65 and older who were paralyzed on one side.
Patients who were deficient in vitamin D were seven times more likely to break a hip than those who had marginal levels of vitamin D. In all cases, a fall caused the hip fracture. None of the patients with normal vitamin D levels sustained a hip fracture during the two-year study.
"An association of low vitamin D levels with hip fracture in older people is reasonably well established," says William J. Gillespie, MD, professor and dean of the Dunedin School of Medicine, University of Otago in New Zealand, who also reviewed the study for WebMD.
Vitamin D deficiency increases parathyroid hormone levels, which triggers rapid bone loss and muscle weakness, making stroke patients even more likely to fall, Deal explains. In the Stroke study, those patients who were older, more disabled, and more severely immobilized were more likely to have low blood levels of vitamin D.
Vitamin D supplementation can protect these stroke patients.
"In 1997, Dr. Sato first drew attention to the effect of [giving vitamin D] and calcium in preventing hip fracture after stroke," Gillespie says.
"These patients often have dramatic responses to vitamin D therapy," Deal says. "Patients who are so weak that they are in a wheelchair will gain significant muscle strength and walk in a few months."
The rationale for vitamin D supplementation was to make the bones denser and less brittle, but it also may reduce the risk of falling. Further research may help settle this issue.
In the meantime, Marc C. Hochberg, MD, MPH, a professor of medicine and epidemiology at the University of Maryland School of Medicine in Baltimore, recommends that all adults aged 65 and over take vitamin D, especially if they are at increased risk for hip fracture.
"Supplementation with calcium and vitamin D," he says, "significantly decreases the risk of hip fracture."