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Paradoxical Relationships Between Vitamin D and Body Composition in Collegiate Athletes Training in the Midwest
Author(s) -
HewButler Tamara,
LandisPiwowar Kristin,
Aprik Carrie,
Byrd Brigid
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.317.7
Subject(s) - basketball , vitamin d and neurology , vitamin , medicine , athletes , bone mineral , zoology , dual energy , endocrinology , physical therapy , biology , osteoporosis , geography , archaeology
Objective To assess both changes and relationships between serum 25‐hydroxyvitamin D (vitamin D) and body composition in NCAA D1 athletes (training latitude 42.6°N) over the Fall season. Methods Student‐athlete volunteers from seven sport teams (men and women's cross country, swimming, and basketball plus women's soccer) were tested both pre‐season (August–September) and post‐season (January–February) for vitamin D (Crittenton Hospital laboratory), and body composition (dual energy x‐ray absorptiometry scan). Data reported as mean±SD with significance set at p<0.05. Results 24 males and 49 females (N=73) completed both pre and post‐season testing. Significant decreases noted in vitamin D (pre‐season vs. post‐season) when all athletes were combined (40±14 vs. 33±13ng/mL;p=0.005;N=73) and more specifically in male basketball (22±8 vs. 15±6ng/mL;p=0.03;n=9) and cross country (47±5 vs. 38±6ng/mL;p=0.001;n=9) athletes. Combined data (N=73) revealed significant inverse relationships between pre‐season vitamin D vs. pre‐season total bone mineral content (BMC; r=−0.32;p=0.005), pre‐season total lean mass (r=−0.36;p=0.002), and post‐season minus pre‐season change (Δ) in total fat mass (r=−0.23;p=0.04). When separated by sex, male athletes demonstrated more robust inverse correlations between pre‐season vitamin D vs. pre‐season: BMC (r=−0.71;p=0.000), bone mineral density (BMD;r=−0.60;p=0.002), and total fat mass (r=−0.61;p=0.001). Male basketball players (n=9) demonstrated the strongest inverse correlations between post‐season vitamin D vs. post‐season BMD (r=−.85;p=0.004) and BMC (r=−.78;p=0.01) despite having the lowest pre‐season and post‐season vitamin D levels and highest (pre‐season and Δ) BMC (3697±404g and 55±86g) and BMD (1.37±0.09g/cm 3 and 0.02±0.02g/cm 3 ). Female athletes demonstrated significant negative relationships between pre‐season vitamin D vs. Δ BMC (r=−.35;p=0.02), Δ %body fat (r=−.34;p=0.02), and Δ total fat mass (r=−0.31;p=0.03). Conclusions Vitamin D levels (on average) decreased in all tested teams, regardless of indoor (swimming and basketball) or outdoor (cross country, soccer) training. No significant relationships were noted between the Δ in Vitamin D vs. the Δ in any total body composition variable. However, significant (inverse) linear relationships were noted at single testing time points (pre‐season or post‐season) between vitamin D versus bone (BMD or BMC), lean and fat mass which were driven largely by the male athletes (particularly the basketball players). Collectively, higher pre‐season vitamin D levels were paradoxically associated with reduced pre‐season bone and muscle (lean) mass with greater fat mass losses (over the season) observed in this cohort of male and female Fall sport athletes. Support or Funding Information Support provided by the Oakland University Athletics Department