Association Between Vitamin D Status and Physical Performance: The InCHIANTI Study

Cross-sectional association between serum vitamin D concentration and walking speed measured at usual and fast pace among older women: The EPIDOS study

“…This strong positive association may be explained by the combined action of vitamin D on muscles and nerves. (5)(6)(7)(8)(9)(10)30) Even if the association of vitamin D with muscular strength remains controversial 5,7 -which was confirmed by the lack of significant linear association between serum 25(OH)D and quadriceps strength in our study-its action on muscle contraction speed and muscle power seems likely. (5,30) It has indeed been shown that serum vitamin D concentrations influence muscular phenotypic determinism because fast-twitch muscle fiber atrophy was identified in adults with vitamin D deficiency.…”

“…(1)(2)(3) Indeed, there is increasing evidence that when accounting not for skeletal health but the salutary effects of vitamin D on nonskeletal organs, the optimal health-promoting concentration of 25(OH)D is around 30 ng/mL. (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) In particular, adverse neuromuscular events such as muscle weakness, balance impairment, and reduced nerve conduction have been described for serum 25(OH)D concentrations below 30 ng/mL. (3)(4)(5)(6)(7)(8)(9)(10)(11) Walking speed is a simple, objective performance-based measure of lower limb neuromuscular function that not only allows detection of subtle impairments and preclinical diseases but also is a sensitive marker of functional capacity in older adults.…”

“…(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) In particular, adverse neuromuscular events such as muscle weakness, balance impairment, and reduced nerve conduction have been described for serum 25(OH)D concentrations below 30 ng/mL. (3)(4)(5)(6)(7)(8)(9)(10)(11) Walking speed is a simple, objective performance-based measure of lower limb neuromuscular function that not only allows detection of subtle impairments and preclinical diseases but also is a sensitive marker of functional capacity in older adults. (10)(11)(12)(13)(14)(15)(16) For instance, Suzuki and colleagues recently demonstrated that walking speed in older adults was positively ORIGINAL ARTICLE J JBMR correlated with physical performance tests such as handgrip strength or stork standing time.…”

“…(16) Furthermore, these authors also found a significant positive association between walking speed at a usual pace and serum 25(OH)D concentrations. (16) Compared with muscle strength or balance performance, (5)(6)(7) fewer attempts have been made to explore the association between low chronic serum 25(OH)D concentrations and walking speed. (10,(16)(17)(18)(19)(20)(21)(22) A better understanding of this association is important to further develop interventional clinical studies to assess the effect of vitamin D supplementation on mobility and gait performance and related adverse health consequences.…”

“…Mixed results also may be explained by the absence or insufficient control of potential confounders such as age, body mass index (BMI), quadriceps strength, cognitive functioning, physical activity, number of chronic diseases, use of psychoactive drugs, and concentrations of serum intact parathyroid hormone (iPTH). (3)(4)(5)(6)(7)(8)(9)(10)(11) Lastly, studies used different cutoff values for low serum 25(OH)D concentrations ranging from 10 to 30 ng/mL, which also may explain the divergent results. (1)(2)(3) Thus, to better understand the association of vitamin D with walking speed, every previously used 25(OH)D threshold must be analyzed: 10, 20, and 30 ng/mL.…”