Higher doses of vitamin D were no more effective than lower doses in improving lower extremity function for elderly patients and were associated with a higher risk of falls,according to a new study.
Two hundred participants,ages 70 and older,were broken into three treatment groups,one receiving 24,000 IU of vitamin D3 monthly,another receiving 60,000 IU,and the third group 24,000 IU plus calcifediol.The second and third groups were more likely than the first after 1 year to reach a serum vitamin D level of at least 30 ng/mL (P=0.001),reported Heike Bischoff-Ferrari,MD,DrPh,of the University Hospital Zurich in Switzerland,and colleagues.
But the supplements were not more effective in improving lower extremity function,which was the same among all the groups,they wrote in JAMA Internal Medicine.
Incidence of falls varied significantly between treatment groups,with the highest incidence in the 60,000 IU group (66.9%,95% CI,54.4%-77.5%) and in the 24,000 IU plus calcifediol group (66.1%,95% CI 53.5%-76.8%).
By comparison,the 24,000 IU group had the lowest prevalence of falls (47.9%,95% CI 35.8%-60.3%,P=0.48),and both the 60,000 IU group and the 24,000 plus calcifediol groups had a nonsignificantly higher mean number of falls (1.47 and 1.24,respectively) than did the 24,000 IU group (0.94,P=0.09).
"High monthly doses of vitamin D or a combination with calcifediol may not be warranted in seniors with a prior fall because of a potentially deleterious effect on falls," the authors stated."Future research is needed to confirm our findings for daily dosing regimens."
There is little evidence that supplementation to achieve 30 ng/mL works,so "it is prudent to get recommended intakes of vitamin D and other vitamins from a balanced diet with foods that naturally contain what is manufactured into supplements," wrote Steven Cummings,MD,of the California Pacific Medical Center Research Institute in San Francisco,and colleagues in an accompanying editorial.
The editorialists stated that until supplementation "is supported by randomized trials with updated meta-analyses,it would be prudent to follow recommendations from the Institute of Medicine (IOM) that people 70 years or older have a total daily intake of 800 IU of vitamin D without routine measurement of serum 25(OH)D levels."
Bischoff-Ferrari and colleagues recruited participants via newspaper advertisements.All participants had a low-trauma fall in the previous 12 months and lived at home.To be included,participants had to be able to walk,use public transportation to attend clinical visits,and be willing to discontinue other calcium and vitamin D supplementation.They also had to score at least a 27 on the Mini-Mental State Examination to show that they understood the procedures and gave consent.
The trial was done at a single center and was double-blinded.Nine of the participants discontinued treatment but researchers kept them in the trial and included them in the analysis of the endpoints.Adherence was greater than 98% in all groups for the first 6 months,and greater than 94% in the last 6 months.The average age of the participants was 78,and 67% were female.
Function was assessed via the Short Physical Performance Battery (SPPB),which included a physical examination,medical history,blood and urine samples,and appendicular muscle mass absorptiometry.Participants were given an SPPB score,which the researchers used as a primary outcome.They did not differ significantly between the treatment groups (P=0.26).
"Clinicians should not recommend vitamin D supplements for other putative health benefits.There is no evidence from meta-analyses of randomized clinical trials that vitamin D supplementation reduces the risk of cardiovascular disease or cancer," wrote Cummings and colleagues.
Tod Cooperman,MD,the president of ConsumerLab.com,which reviews supplements,wrote in an email to MedPage Today that excess vitamin D supplementation can be a problem.
"People with higher levels tend to have more bone fractures,heart disease,cancer,and even die sooner than those with lower,but sufficient levels," he wrote."Studies with high versus low doses not only show an increase in falls,but an increase in upper respiratory infections."
He added that there's been an increase in overdoses because of misleading information from labs,and some doctors and patients believing more is better when it comes to the vitamin.
The study authors added that there are two vitamin D trials underway -- the VITAL trial and the DO-HEALTH trial -- that will use doses of 60,000 IU,but those trial doses are daily rather than monthly,and the patient populations will differ.
Limitations of the study include a lack of generalizability to younger seniors and the lack of a placebo group.