Vitamin D Supplementation Ineffective in Preventing Falls, Fractures

High-dose vitamin D supplementation has no significant clinical effect in preventing falls and fractures, according to study findings in Osteoporosis International. 

Researchers conducted a meta-analysis to determine whether intermittent or single high-dose oral or intramuscular vitamin D supplementation can help prevent falls and fractures.

Data was collected from PubMed, EMBASE, and the Cochrane Library. The Jadad scale was used to assess study quality and the Cochrane Risk of Bias Tool was also utilized. 

A total of 527 articles were identified and 15 articles were included in the final analysis. Exclusion criteria were daily vitamin D supplementation, irrelevant studies, identical study populations, unpublished data, and review articles. 

All studies were conducted from 1992 through 2021 and included 30,247 participants with 15,461 in the experimental group and 15,585 in the control group. There were 6 studies conducted in the United Kingdom, 3 studies in Australia, 2 studies in the United States, 1 in Finland, 1 in New Zealand, 1 in Switzerland, and 1 in New Zealand/Australia. 

The mean age of study participants was 76.0 years for falls and 77.2 years old for fractures. Across all studies, the number of participants ranged from 86 to 9440 and 59.2% of participants were women. 

The types of vitamin D used were vitamin D2 (ergocalciferol; n=6) and vitamin D3 (cholecalciferol; n=10). There were 12 studies using oral vitamin D and 4 studies using intramuscular Vitamin D. 

The outcomes assessed across studies were falls and fractures (n=7), falls only (n=5), fractures only (n=3), and fracture union (n=1). Of the 15 studies included in the analysis, 12 used a placebo for the control population and 3 used no treatment. 

A meta-analysis of the 15 studies revealed that both intermittent or single high-dose vitamin D supplementation have no significant benefits in preventing falls ​​(risk ratio [RR], 1.03; 95% CI, 0.98-1.09; I², 56.6%; n=11) or fractures (RR, 0.99; 95% CI, 0.87-1.14; I², 48.3%; n=11). There was no publication bias reported for these studies. 

Subgroup analysis showed that vitamin D supplementation increased the risk for falls (RR, 1.06; 95% CI, 0.99-1.15; P =.051; I², 50.0%; n=7) but results were on the borderline of statistical significance. Subgroup data showed no significant benefits of vitamin D supplementation regarding the risk for fractures. 

Subgroup meta-analysis of studies including fewer than 1000 patients showed a reduction in risk for fractures (RR, 0.74; 95% CI, 0.57-0.96; I², 0.0%; n=5), but this benefit is not observed for studies with 1000 participants or more (RR, 1.06; 95% CI, 0.92-1.21; I², 57.5%; n=6).

Study limitations are lack of generalizability to people outside of Western countries and the inability to conduct subgroup meta-analysis according to baseline serum vitamin D. 

“…measurement of vitamin D levels has increased, and intermittent or single high-dose oral or intramuscular vitamin D supplementation has been inadequately over-prescribed in generally healthy people who are not deficient in vitamin D,” the study authors wrote.