Seasonal variation in vitamin D status, bone health and athletic performance in competitive university student athletes: a longitudinal study

J Nutr Sci. 2020 Feb 10;9:e8. doi: 10.1017/jns.2020.1.


Vitamin D deficiency has been commonly reported in elite athletes, but the vitamin D status of UK university athletes in different training environments remains unknown. The present study aimed to determine any seasonal changes in vitamin D status among indoor and outdoor athletes, and whether there was any relationship between vitamin D status and indices of physical performance and bone health. A group of forty-seven university athletes (indoor n 22, outdoor n 25) were tested during autumn and spring for serum vitamin D status, bone health and physical performance parameters. Blood samples were analysed for serum 25-hydroxyvitamin D (s-25(OH)D) status. Peak isometric knee extensor torque using an isokinetic dynamometer and jump height was assessed using an Optojump. Aerobic capacity was estimated using the Yo-Yo intermittent recovery test. Peripheral quantitative computed tomography scans measured radial bone mineral density. Statistical analyses were performed using appropriate parametric/non-parametric testing depending on the normality of the data. s-25(OH)D significantly fell between autumn (52·8 (sd 22·0) nmol/l) and spring (31·0 (sd 16·5) nmol/l; P < 0·001). In spring, 34 % of participants were considered to be vitamin D deficient (<25 nmol/l) according to the revised 2016 UK guidelines. These data suggest that UK university athletes are at risk of vitamin D deficiency. Thus, further research is warranted to investigate the concomitant effects of low vitamin D status on health and performance outcomes in university athletes residing at northern latitudes.

Keywords: AF, aerobic fitness; Athletic performance; Bone; Muscle strength; PTH, parathyroid hormone; Physiology; University athletes; Vitamin D.

Publication types

  • Observational Study

MeSH terms

  • Athletes*
  • Athletic Performance*
  • Bone Density
  • Bone and Bones*
  • Dietary Supplements
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Muscle Strength
  • Parathyroid Hormone
  • Seasons
  • Students*
  • Surveys and Questionnaires
  • Universities*
  • Vitamin D / analogs & derivatives
  • Vitamin D / blood*
  • Vitamin D Deficiency / blood
  • Young Adult


  • Parathyroid Hormone
  • Vitamin D
  • 25-hydroxyvitamin D