Thesis

Vitamin D Status and Performance in Semi-Professional Male Rugby Union Players: A Cross-Sectional Analysis

Publisher
Sport Health Elite athletes Pacific Area
Description

Background: Low vitamin D status is common amongst the athletic population internationally. Sufficient vitamin D is important for bone health and recent research also suggests an importance for physical performance, with associations found between serum 25-hydroxyvitamin D concentrations and muscle strength and physical performance in healthy populations. However, these associations have not been assessed in New Zealand athletes.Objectives: The objectives were to 1) evaluate the vitamin D status of semi-professional male rugby union players in Otago and Southland, New Zealand; 2) within this group, to assess associations between serum 25-hydroxyvitamin D concentrations and specific athletic performance measures; and 3) to identify potential predictors of serum 25-hydroxyvitamin D concentrations in this group of New Zealand athletes.Design: Cross-sectional secondary data analysis of a randomised, placebo-controlled, double-blinded intervention study.Methods: Fifty-seven semi-professional male rugby union players residing in Otago and Southland, New Zealand (latitude: 45-47° S) completed baseline measures including: a demographic questionnaire, sun exposure questionnaire, serum 25-hydroxyvitamin D analysis and standard New Zealand Rugby Union performance tests during the months of autumn (March to May), 2011.Results: The mean serum 25-hydroxyvitamin D concentration was 94 nmol/L (range, 57-131 nmol/L). No participant had a serum 25-hydroxyvitamin D concentration of 50 nmol/L. There were no associations between serum 25-hydroxyvitamin D concentrations and the specific measures of athletic performance, suggesting that athletic performance is not associated with circulating 25-hydroxyvitamin D. Participants of self-identified Pacific ethnicity had significantly lower serum 25-hydroxyvitamin D concentrations compared to those of self-identified New Zealand European and Māori ethnicities. Self-identified Pacific ethnicity was a significant predictor of serum 25-hydroxyvitamin D concentrations.

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