Researchers looking at vitamin D levels in elite ballet dancers have found that deficiency caused by intensive indoor training leads to increased risk of injury.
The researchers at the Royal National Orthopaedic hospital (RNOH), University of Wolverhampton and the Jerwood Centre at Birmingham Royal Ballet said that the results saw knowledge of vitamin D deficiency’s effect extending to muscle function.
The research, published in the Journal of Science and Medicine in Sport Treatment, could pose a practical solution for the dance sector since lost time due to injury can be costly for both company and dancer.
The study also found significant results suggesting the effect of oral contraception on bone metabolism- which controls the process of reshaping and replacement of bone after an injury.
Out of the sun
Serum 25-hydroxyvitamin D levels produced by the exposure of the skin to sunlight, along with parathyroid hormone (PTH), blood serum bone turnover markers and injury data were monitored in 19 elite classical ballet dancers over a six month period.
The study aimed to look at the serum 25-hydroxyvitamin D status in UK professional dancers during periods of reduced and increased sunlight exposure – in winter and summer – and to assess the impact on bone metabolism and risk of injury.
During the winter all 19 dancers were either insufficient (14) or deficient (5) in serum 25(OH)D, which marginally improved in summer.
The study also found that there was a higher injury incidence in the winter. The researchers concluded that oestrogen-containing oral contraception seemed to increase serum 25(OH)D levels and have a positive effect on bone metabolism.
“This may be due to the fact that oral contraceptive can alter the relative proportions of free and protein bound 25(OH)D by influencing levels of vitamin D binding protein thereby causing the observed increase in serum 25(OH)D levels,” wrote the researchers.
The scientists also noted that soft tissue injuries were significantly lower in summer compared to winter periods, though no significant association with serum 25(OH)D categories were noted.
Source: Journal of Science and Medicine in Sport
Vol. 16, Iss. 5, pp. 388-391, http://dx.doi.org/10.1016/j.jsams.2012.12.010
“Vitamin D status in professional ballet dancers: Winter vs. summer”
Authors: R. Wolman, M.A. Wyon, Y. Koutedakis, AM. Nevill, R. Eastell, N. Allen