Too Much Vitamin D: More Falls and Fractures
Reported May 14, 2010
(Ivanhoe Newswire) — Women age 70 years or older who received a single annual high dose of vitamin D had a higher rate of falls and fractures than did women who received placebo.
Kerrie M. Sanders, Ph.D., of the University of Melbourne, Geelong, Australia and colleagues conducted a study to examine whether high-dose cholecalciferol (vitamin D) given orally once a year to older women would reduce falls and fractures. The vitamin D was given in a single, high-dose to address low adherence. The trial included 2,256 community-dwelling women, ages 70 years or older, considered to be at high risk of fracture. They were recruited from June 2003 to June 2005 and were randomly assigned to receive 500,000 IU of vitamin D or placebo each year for 3 to 5 years. The study concluded in 2008.
The trial participants had a total of 5,404 falls over the study period, with 74 percent of women in the vitamin D group and 68 percent of women in the placebo group having at least one fall. Analysis indicated women in the annual high-dose vitamin D group experienced 15 percent more falls. Women in the vitamin D group had 171 fractures vs. 135 in the placebo group, with 26 percent more fractures for participants in the vitamin D group, who also had a 31 percent higher incidence of falls in the first 3 months following dosing.
“This is the first study to demonstrate increased risk of falls associated with any vitamin D intervention and the second study to demonstrate an increased fracture risk associated with annual high-dose vitamin D therapy in elderly women.
“This line of reasoning is supported by the temporal risk pattern that we observed and the fact that harm has not been reported in the numerous studies that have used more frequent dosing. Thus, it is reasonable to speculate that high serum levels of vitamin D or metabolites resulting from the large annual dose, subsequent decrease in the levels, or both might be causal.”
SOURCE: Journal of the American Medical Association (JAMA), May 12, 2010