Harrison, SE, Oliver, SJ, Kashi, DS, Carswell, AT, Edwards, JP, Wentz, LM, Roberts, R, Tang, JCY, Izard, RM, Jackson, S, Allan, D, Rhodes, LE, Fraser, WD, Greeves, JP and Walsh, NP (2021) Influence of Vitamin D Supplementation by Simulated Sunlight or Oral D3 on Respiratory Infection during Military Training. Medicine and Science in Sports and Exercise, 53 (7). pp. 1505-1516. ISSN 1530-0315
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Influence of Vitamin D Supplementation by Simulated Sunlight or Oral D3 on Respiratory Infection during Military Training.pdf - Published Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (893kB) | Preview |
Abstract
PURPOSE: To determine the relationship between vitamin D status and upper respiratory tract infection (URTI) of physically active men and women across seasons (study 1). Then, to investigate the effects on URTI and mucosal immunity of achieving vitamin D sufficiency (25(OH)D ≥50 nmol·L-1) by a unique comparison of safe, simulated-sunlight or oral D3 supplementation in winter (study 2). METHODS: In study 1, 1,644 military recruits were observed across basic military training. In study 2, a randomized controlled trial, 250 men undertaking military training received either placebo, simulated-sunlight (1.3x standard erythemal dose, three-times-per-week for 4-weeks and then once-per-week for 8-weeks) or oral vitamin D3 (1,000 IU·day-1 for 4-weeks and then 400 IU·day-1 for 8-weeks). URTI was diagnosed by physician (study 1) and Jackson common cold questionnaire (study 2). Serum 25(OH)D, salivary secretory immunoglobulin A (SIgA) and cathelicidin were assessed by LC-MS/MS and ELISA. RESULTS: In study 1, only 21% of recruits were vitamin D sufficient during winter. Vitamin D sufficient recruits were 40% less likely to suffer URTI than recruits with 25(OH)D <50 nmol·L-1 (OR (95% CI) = 0.6 (0.4-0.9)); an association that remained after accounting for sex and smoking. Each URTI caused on average 3 missed training days. In study 2, vitamin D supplementation strategies were similarly effective to achieve vitamin D sufficiency in almost all (≥95%). Compared to placebo, vitamin D supplementation reduced the severity of peak URTI symptoms by 15% and days with URTI by 36% (P < 0.05). These reductions were similar with both vitamin D strategies (P > 0.05). Supplementation did not affect salivary SIgA or cathelicidin. CONCLUSION: Vitamin D sufficiency reduced the URTI burden during military training.
Item Type: | Article |
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Uncontrolled Keywords: | 1106 Human Movement and Sports Sciences, 1116 Medical Physiology, 1117 Public Health and Health Services |
Subjects: | R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine R Medicine > RC Internal medicine > RC1200 Sports Medicine |
Divisions: | Sport & Exercise Sciences |
Publisher: | American College of Sports Medicine |
Related URLs: | |
Date Deposited: | 28 Jan 2021 11:35 |
Last Modified: | 04 Sep 2021 06:04 |
DOI or ID number: | 10.1249/MSS.0000000000002604 |
URI: | https://researchonline.ljmu.ac.uk/id/eprint/14333 |
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