title: The effect of body composition and BMI on 25(OH)D response in vitamin D-supplemented athletes.
abstract: Fat mass is inversely associated with vitamin D status, and athletes with the most adipose tissue may have the greatest risk for insufficient (25(OH)D 20-32 ng mL(-1)) or deficient (25(OH)D < 20 ng ml(-1)) status. The effects of fat and lean mass on 25(OH)D change in response to vitamin D supplementation have yet to be elucidated in athletes. In addition, vitamin D has a known role in bone health yet a link between short-term changes in 25(OH)D and bone turnover in indoor athletes have not yet been described. Thirty-two collegiate swimmers and divers (19 male, 13 female; 19 (1) years) participated in a 6-month randomized controlled trial and consumed either 4000 IU d(-1) of vitamin D3 (n = 19) or placebo (PLA; n = 13). Anthropometry and blood collection of 25(OH)D, bone-specific alkaline phosphatase (B-ALP) and N-terminal telopeptide (NTx) occurred at three time points. Dual-energy X-ray absorptiometry measured body composition analysis at baseline and endpoint. In the vitamin D group, BMI was negatively correlated with 6-month 25(OH)D change (R = -0.496; P = .03) and a stronger predictor of 25(OH)D change (P = .04) than ultraviolet B exposure and fat mass change. Athletes in the high bone turnover group showed significantly greater losses of 25(OH)D over 6-months compared to athletes in the low bone turnover group (P = .03). These results suggest athletes within the normal BMI category experience a diminished response to 4000 IU d(-1) of vitamin D3 supplementation, and periods of high bone turnover may be an additional risk factor for developing compromised vitamin D status in athletes.
authors.affiliation: a Division of Pulmonary, Critical Care and Sleep Medicine , University of Kentucky , Lexington , KY , USA.
authors.forename: Evan P
authors.initials: EP
authors.lastname: Cassity
authors.affiliation: b Department of Pharmacology and Nutritional Sciences , University of Kentucky , Lexington , KY , USA.
authors.forename: Maja
authors.initials: M
authors.lastname: Redzic
authors.affiliation: c College of Health Sciences , University of Kentucky , Lexington , KY , USA.
authors.forename: Cassidy R
authors.initials: CR
authors.lastname: Teager
authors.affiliation: c College of Health Sciences , University of Kentucky , Lexington , KY , USA.
authors.forename: D Travis
authors.initials: DT
authors.lastname: Thomas
mesh_terms: D000328:Adult; D056352:Athletes; D001823:Body Composition / Q000187:drug effects / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D008297:Male; D013550:Swimming / Q000502:physiology; D014807:Vitamin D / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D006887:Hydroxycholecalciferols; D014807:Vitamin D
keywords: BMI; Bone turnover; fat mass; swimmer