Vitamin D status in professional ballet dancers: Winter vs. summer.

J Sci Med Sport. 2013 Feb 1. pii: S1440-2440(12)01139-5. doi: 10.1016/j.jsams.2012.12.010.
Wolman R, Wyon MA, Koutedakis Y, Nevill AM, Eastell R, Allen N.

Department of Rheumatology and Sport and Exercise Medicine, Royal National Orthopaedic Hospital, Stanmore, UK; National Institute of Dance Medicine and Science, UK.

OBJECTIVE: Serum 25-hydroxyvitamin D is produced by the exposure of the skin to sunlight. Therefore athletes who train indoors, such as dancers, are vulnerable to vitamin D deficiency. The purpose of the study was to evaluate the serum 25-hydroxyvitamin D status in UK professional dancers during periods of reduced and increased sunlight exposure (i.e., winter vs. summer), and to assess the impact on bone metabolism and risk of injury.

DESIGN: Cohort study.

METHODS: 19 elite classical ballet dancers (age 26±8.86yr; height 1.66±8.84m; mass 54.3±10.47kg) were monitored over a 6 month period for 25-hydroxyvitamin D, PTH and blood serum bone turnover markers (CTX and PINP) along with injury data. Repeated measure ANOVA and Wilcoxon and Chi-square analyses were used and significance was set at p≤0.05.

RESULTS: Significant changes were noted between the winter and summer test dates for 25-hydroxyvitamin D (14.9ng/ml vs. 23.9ng/ml; p<0.001), PTH (38.7pg/ml vs. 26.3pg/ml; p<0.001) and PINP (89.9ng/ml vs. 67.6ng/ml; p<0.01). The oral contraceptive had a significant effect on serum 25-hydroxyvitamin D, PTH and CTX. Soft tissue injuries were significantly lower in summer compared to winter period (winter=24, summer=13; p<0.05).

CONCLUSIONS: Professional ballerinas characterized by a high incidence of low serum 25-hydroxyvitamin D levels which improve marginally in the summer. These dancers also demonstrate a higher injury incidence in the winter. Oral contraception seems to increase serum 25-hydroxyvitamin D levels and has a positive effect on bone metabolism.

Copyright © 2013. Published by Elsevier Ltd.

PMID: 23379989

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See also VitaminDWiki

• Overview Sports and vitamin D
• Half as many fractures for girls with high vitamin D intake – March 2012
• Athletes need at least 40 ng of vitamin D – literature review Oct 2012
• Female Athlete health problems may be due to lack of vitamin D and Iron – July 2012
  note - the pill which reduces bleeding, and thus increases Iron, increased vitamin D levels
     Iron deficiency is a cause of Vitamin D deficiency perhaps normal menses as well.
• Basketball players low on vitamin D - Sept 2011 another indoor sport
• Ballet Dancers with low D had 50 percent more injuries – pilot study Sept 2011
• Fewer injuries and higher ballet jumps with 2,000 IU of vitamin D – April 2013 many of the same authors as the study on this page
• Shin splints decrease with vitamin D
• All items in category Iron and Vitamin D 68 items
• Large seasonal variation in vitamin D levels associated with poor bone health – Aug 2013

See also web

• Vitamin D deficiency puts elite ballet dancers at risk of injury The Guardian Nov 2013
  Treatment of professional dancers of all kinds costs on average £900,000 a year and £1m in lost time, making it a significant issue for the subsidised dance sector.