posted on 2015-03-12, 13:50authored byCheng-Shiun He, Michal K. Handzlik, William D. Fraser, Ayu S. Muhamad, H. Preston, A. Richardson, Michael Gleeson
The purpose of this study was to examine the influence of vitamin D status on
mucosal and systemic immunity and the incidence, severity and duration of upper
respiratory tract illness (URTI) episodes in endurance athletes during a 16-week
winter training period. Blood was collected from 225 subjects at the start of the
study and plasma was analysed for total 25-hydroxy vitamin D (25(OH)D) and
cathelicidin concentration. Blood was also collected at the end of the study and
analysed for 25(OH)D and antigen-stimulated cytokine production. Unstimulated
saliva samples were obtained at the start and at 4-week intervals during the study
period. Saliva samples were analysed for salivary antimicrobial peptides and
proteins (AMPs). Weekly training and daily illness logs were kept. At the start
and end of the study 38% and 55%, respectively, of the athlete cohort had inadequate
(plasma 25(OH)D 30-50 nmol/L) or deficient (plasma 25(OH)D <30
nmol/L) vitamin D status. There was a significantly higher proportion of subjects
who presented with symptoms of URTI in the vitamin D deficient status group
(initial plasma 25(OH)D <30 nmol/L) during the study period than in the optimal
vitamin D group ( >120 nmol/L) and the total number of URTI symptom days and
the median symptom-severity score in the vitamin D deficient group was significantly higher than in the other groups. The plasma cathelicidin concentration
positively correlated with the plasma 25(OH)D concentration and the saliva
secretory immunoglobulin A (SIgA) secretion rate in the optimal vitamin D status
group was significantly higher than in the other groups. Low vitamin D status
was associated with lower pro-inflammatory cytokine production by monocytes
and lymphocytes. Low vitamin D status could be an important determinant of
URTI risk in endurance athletes and mucosal as well as systemic immunity may
be modified via vitamin D-dependent mechanisms.
Funding
Gatorade Sport Science Institute
History
School
Sport, Exercise and Health Sciences
Published in
EXERCISE IMMUNOLOGY REVIEW
Volume
19
Pages
86 - 101 (16)
Citation
HE, C-S. ... et al., 2013. Influence of vitamin D status on respiratory infection incidence and immune function during 4 months of winter training in endurance sport athletes. Exercise Immunology Review, 19, pp.86-101.
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