title: Seasonal Variation in Vitamin D Status in Elite Athletes: A Longitudinal Study.
abstract: Studies monitoring vitamin D status in athletes are seldom conducted for a period of 12 months or longer, thereby lacking insight into seasonal fluctuations. The objective of the current study was to identify seasonal changes in total 25-hydroxyvitamin D (25(OH)D) concentration throughout the year. Fifty-two, mainly Caucasian athletes with a sufficient 25(OH)D concentration (>75 nmol/L) in June were included in this study. Serum 25(OH)D concentration was measured every three months (June, September, December, March, June). In addition, vitamin D intake and sun exposure were assessed by questionnaires at the same time points. Highest total 25(OH)D concentrations were found at the end of summer (113 ± 26 nmol/L), whereas lowest concentrations were observed at the end of winter (78 ± 30 nmol/L). Although all athletes had a sufficient 25(OH)D concentration at the start of the study, nearly 20% of the athletes were deficient (<50 nmol/L) in late winter.
authors.forename: Evelien
authors.initials: E
authors.lastname: Backx
authors.forename: Cindy
authors.initials: C
authors.lastname: van der Avoort
authors.forename: Michael
authors.initials: M
authors.lastname: Tieland
authors.forename: Kamiel
authors.initials: K
authors.lastname: Maase
authors.forename: Arie
authors.initials: A
authors.lastname: Kies
authors.forename: Luc
authors.initials: L
authors.lastname: van Loon
authors.forename: Lisette
authors.initials: L
authors.lastname: de Groot
authors.forename: Marco
authors.initials: M
authors.lastname: Mensink
mesh_terms: D000293:Adolescent; D000328:Adult; D056352:Athletes; D015992:Body Mass Index; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009426:Netherlands; D009752:Nutritional Status; D012189:Retrospective Studies; D012621:Seasons; D064133:Sports Nutritional Physiological Phenomena; D013472:Sunlight; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood*; D055815:Young Adult
chemical_list: D014807:Vitamin D
keywords: 25(OH)D; sports nutrition