Postural Balance Effects Associated with 400, 4000 or 10,000 IU Vitamin D3 Daily for Three Years: A Secondary Analysis of a Randomized Clinical Trial

Abstract

Vitamin D supplementation is proposed as a fall prevention strategy, as it may improve neuromuscular function. We examined whether three years of vitamin D supplementation (400, 4000 or 10,000 IU daily) affects postural sway in older adults. Three hundred and seventy-three non-osteoporotic, vitamin D-sufficient, community-dwelling healthy adults, aged 55–70 years, were randomized to 400 (n = 124), 4000 (n = 125) or 10,000 (n = 124) IU daily vitamin D3 for three years. Sway index was assessed at baseline, 12-, 24- and 36-months using the Biosway machine. We tested participants under four conditions: eyes open or eyes closed with firm (EOFI, ECFI) or foam (EOFO, ECFO) surfaces. Secondary assessments examined sway in the anterior-posterior (AP) and medio-lateral (ML) directions. Linear mixed effects models compared sway between supplementation groups across time. Postural sway under EOFO and ECFO conditions significantly improved in all supplementation groups over time. Postural sway did not differ between supplementation groups at any time under any testing conditions in normal, AP or ML directions (p > 0.05 for all). Our findings suggest that high dose (4000 or 10,000 IU) vitamin D supplementation neither benefit nor impair balance compared with 400 IU daily in non-osteoporotic, vitamin D-sufficient, healthy older adults.

Vitamin D supplementation: upper limit for safety revisited?

“…In the same study, areal BMD did not change irrespective of the dose [43]. Along this line, postural sway was not affected between daily doses of vitamin D of 400, 4000 and 10,000 [44], vitamin D daily equivalent of 5700 IU was not different from 800 IU in terms of muscle strength and balance [45], changes in muscle strength and mass were not different in the 40,000 IU/week vitamin D2 (equivalent to 5700 IU/day) and placebo groups [46], whilst 1000 IU/day increased lower limb muscle strength [47]. In a systematic review and meta-analysis published in 2011, the conclusion was that daily doses of 800 to 1000 IU consistently demonstrated beneficial effects on muscle strength and balance [48].…”

Test‐Retest Reliability of Postural Control Assessment on Biodex BioSway™

“…Many studies which have utilized the Biodex Biosway™ for assessment of postural sway or compared the Biodex Biosway™ to other devices have reported that this is a reliable assessment tool [8][9][10][11][12][13][14][15]. However, on closer examination, these same studies have supported this claim by citing reliability studies which were actually performed on a separate hardware system designed for dynamic posturography, the Biodex Balance System [16][17][18].…”