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Amanda Zaleski, Beth Taylor, Braden Armstrong, Michael Puglisi, Priscilla Clarkson, Stuart Chipkin, Charles Michael White, Paul D. Thompson and Linda S. Pescatello

Insufficient 25-hydroxyvitamin D [25(OH)D] levels are associated with high resting blood pressure (BP). However, the relationship between 25(OH)D and the peak systolic BP (SBP) response to exercise, a predictor of future hypertension, has yet to be investigated. We sought to examine the relationship among serum 25(OH)D and the peak SBP response to a graded exercise stress test (GEST) among a large sample (n = 417) of healthy men (49%) and women (51%) over a broad age range (20–76 years; mean age: 44.1 ± 0.8 years). We hypothesized that individuals with clinically insufficient 25(OH)D would have a greater peak SBP response to a GEST compared to individuals with sufficient 25(OH)D levels. Fasting serum 25(OH)D, anthropometrics, resting BP, and peak exercise SBP were obtained at the baseline visit of a larger clinical trial (STOMP; NCT01140308). Mean 25(OH)D levels were 36.1 ± 0.7 ng/ml, with ∼35% of individuals classified as insufficient (<30 ng/ml). Average resting BP was 119 ± 13 mmHg/75 ± 10 mmHg, with 52.3% considered to have normal BP, while 25.2% had elevated BP and 22.5% had established hypertension. The peak SBP response to a GEST was similar between individuals with sufficient (48 ± 19 mmHg) versus insufficient (48 ± 18 mmHg) 25(OH)D (p = 1.000). One unexpected finding emerged such that individuals with sufficient 25(OH)D had higher resting SBP (120 ± 14 mmHg vs. 117 ± 13 mmHg; p = .020) than individuals with insufficient 25(OH)D. In contrast to our hypothesis, 25(OH)D levels were not associated with the peak SBP response to a GEST. Baseline 25(OH)D levels were positively correlated with resting SBP; however, the magnitude of this effect is likely not clinically meaningful.

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Pamela J. Magee, L. Kirsty Pourshahidi, Julie M. W. Wallace, John Cleary, Joe Conway, Edward Harney and Sharon M. Madigan

Background:

A high prevalence of vitamin D insufficiency/deficiency, which may impact on health and training ability, is evident among athletes worldwide. This observational study investigated the vitamin D status of elite Irish athletes and determined the effect of wintertime supplementation on status.

Methods:

Serum 25-hydroxyvitamin D [25(OH)D], calcium, and plasma parathyroid hormone were analyzed in elite athletes in November 2010 (17 boxers, 33 paralympians) or March 2011 (34 Gaelic Athletic Association [GAA] players). A subset of boxers and paralympians (n = 27) were supplemented during the winter months with either 5,000 IU vitamin D3/d for 10–12 weeks or 50,000 IU on one or two occasions. Biochemical analysis was repeated following supplementation.

Results:

Median 25(OH)D of all athletes at baseline was 48.4 nmol/L. Vitamin D insufficiency/deficiency (serum 25(OH)D <50 nmol/L) was particularly evident among GAA players (94%) due to month of sampling. Wintertime supplementation (all doses) significantly increased 25(OH)D (median 62.8 nmol/L at baseline vs. 71.1 nmol/L in April or May; p = .001) and corrected any insufficiencies/deficiencies in this subset of athletes. In contrast, 25(OH)D significantly decreased in those that did not receive a vitamin D supplement, with 74% of athletes classed as vitamin D insufficient/deficient after winter, compared with only 35% at baseline.

Conclusions:

This study has highlighted a high prevalence of vitamin D insufficiency/deficiency among elite Irish athletes and demonstrated that wintertime vitamin D3 supplementation is an appropriate regimen to ensure vitamin D sufficiency in athletes during winter and early spring.

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Gal Dubnov-Raz, Netachen Livne, Raanan Raz, Avner H. Cohen and Naama W. Constantini

It is hypothesized that vitamin D insufficiency in athletes might negatively affect sport performance. The objective of this study was to examine the effect of vitamin D3 supplementation on physical performance of adolescent swimmers with vitamin D insufficiency. Fifty-three adolescent competitive swimmers with vitamin D insufficiency (serum 25-hydroxyvitamin-D concentrations (25(OH)D)<30ng/ml, mean 24.2 ± 4.8ng/ml) were randomized to receive 2,000IU/day of vitamin D3 or placebo for 12 weeks. Swimming performance at several speeds, arm-grip strength, and one-legged balance, were measured before and after supplementation. The age-adjusted changes in performance variables during the study were compared between groups. 25(OH) D concentrations at study end were significantly higher in the vitamin group compared with the placebo group (29.6 ± 6.5ng/ml vs. 20.3 ± 4.2ng/ml, p < .001), yet only 48% of the vitamin group became vitamin D sufficient with this dosing. No between-group differences were found in the changes of the performance variables tested. No significant differences in performance were found between participants that became vitamin D sufficient, and those who did not. No significant correlation was found between the change in serum 25(OH)D and ageadjusted balance, strength or swimming performance at study end. Vitamin D3 supplementation that raised serum 25(OH)D concentrations by a mean of 9.3ng/ml above placebo in adolescent swimmers with vitamin D insufficiency, did not improve physical performance more than placebo.

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Gal Dubnov-Raz, Harri Hemilä, Avner H. Cohen, Barak Rinat, Lauryn Choleva and Naama W. Constantini

Observational studies identified associations between vitamin D insufficiency (serum 25(OH)D > 30ng·ml−1) and risk of upper respiratory infection (URI). Swimmers are highly prone to URIs, which might hinder their performance. The aim of this study was to examine if vitamin D3 supplementation reduces URI burden in vitamin D-insufficient swimmers. Fifty-five competitive adolescent swimmers with vitamin D insufficiency were randomized to receive vitamin D3 (2,000IU·d4) or placebo for 12 winter weeks. A URI symptom questionnaire was completed weekly. Serum 25(OH)D concentrations were measured by radio-immunoassay before and after supplementation. We used linear regression to examine the relation between the change in 25(OH)D concentrations during the trial, and the duration and severity of URIs. There were no between-group differences in the frequency, severity, or duration of URIs. Exploratory analyses revealed that in the placebo group only, the change in 25(OH)D concentrations during the trial was highly associated with the duration of URIs (r = −0.90,p > .001), and moderately associated with the severity of URIs (r = −0.65,p = .043). The between-group differences for duration were highly significant. Vitamin D3 supplementation in adolescent swimmers with vitamin D insufficiency did not reduce URI burden. However, larger decreases in serum 25(OH)D concentrations were associated with significantly longer and more severe URI episodes.

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Kirsty A. Fairbairn, Ingrid J.M. Ceelen, C. Murray Skeaff, Claire M. Cameron and Tracy L. Perry

-controlled intervention study, in which the players were randomly allocated 1:1 to receive either a 50,000 IU (1.25 mg) cholecalciferol tablet (pharmaceutical grade: Cal.D.Forte, PSM Healthcare, Auckland NZ), or a similar placebo (NZ Nutritionals, Christchurch NZ) once a fortnight for 11–12 weeks. Players were not

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Kelly Pritchett, Robert C. Pritchett, Lauren Stark, Elizabeth Broad and Melissa LaCroix

(cholecalciferol; Klean Athlete, Pittsburgh, PA) supplementation protocol from the United States Olympic Committee. Performance measures were assessed using handgrip strength and 20-m wheelchair sprints pre- and postsupplementation. Participants completed a 24-hr dietary recall prior to each testing session

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Matthew A. Wyon, Roger Wolman, Nicolas Kolokythas, Karen Sheriff, Shaun Galloway and Adam Mattiussi

often insufficient to meet vitamin D needs in both children and adults. 5 The relatively limited amounts of dietary vitamin D can be obtained as either cholecalciferol (vitamin D3 through oily fish and dairy products) or ergocalciferol (vitamin D 2 through plant extracts). Therefore, sun exposure in