Difference in Levels of Vitamin D between Indoor and Outdoor Athletes: A Systematic Review and Meta-Analysis

The effect of aquatic training and vitamin D3 supplementation on bone metabolism in postmenopausal obese women

Purpose

Despite prevalence of studies indicating the positive effect of land-based exercise on bone metabolism, there are limited findings regarding the effect of aquatic exercise. The present study aimed to evaluate the effects of aquatic training and vitamin D3 supplementation on femur bone mineral density (BMD), serum 25(OH)D, and parathyroid hormone (PTH) in postmenopausal obese women with vitamin D insufficiency.

Methods

40 postmenopausal obese women were randomly divided into four groups of aquatic training + vitamin D3 intake group; (ATD), aquatic training with placebo intake group (AT), vitamin D3 intake group (D), and control group with placebo intake (CON). AT groups performed aerobic aquatic exercises for 8 weeks. Vitamin D3 supplementation groups consumed oral dose of 4000 IU/d for 8 weeks.

Results

The femur BMD was significantly higher in the ATD than the AT and D and CON groups; in AT it was higher than the D and CON groups. Serum 25(OH)D level in the ATD was more than AT and CON, and in the D was more than the CON and AT. PTH in the ATD group was lower compared to AT, D, and CON groups. PTH was lower in the AT and D compared to the CON.

Conclusion

In postmenopausal obese women with vitamin D insufficiency or deficiency, combining vitamin D supplementation and aquatic training was the most effective method for improving bone metabolism; Vitamin D supplementation (alone) was not sufficient to affect some of bone metabolism indices; Aquatic training could not improve serum vitamin D. By priority, ATD, AT, and D indicated better bone related metabolism indices.

VITAMIN D AND INJURIES IN DANCERS: A SYSTEMATIC REVIEW

Vitamin D is involved in many different functions in the human body. Despite the well-known benefits of vitamin D and increasing trends of testing and supplementation, there is still a high prevalence of vitamin D deficiency worldwide, present in the general but also in the highly-active population such as athletes and dancers. Dancers are at a higher risk of vitamin D deficiency due to their long working hours spent indoors, without exposure to sunlight. The high level of workload and physical demands also put dancers at a high risk of injuries. The aim of this review was to systematically analyze the existing evidence on the association of vitamin D (serum level and supplementation) and injuries in dancers. Medline, Scopus, SportDiscus and Web of Science were searched to identify the available peer-reviewed articles. Five articles met the inclusion criteria (two interventional and three observational studies), three of which additionally investigated the relationship between vitamin D and muscle function. The reported results on positive influence of vitamin D serum level or vitamin D supplementation effect on reduced injury occurrence and enhanced muscular function in adolescent and elite professional ballet dancers are promising but the evidence is limited due to a low number of studies, small samples, and methodological limitations.