title: Serum 25-hydroxyvitamin D in early autumn to ensure vitamin D sufficiency in mid-winter in professional football players.
abstract: OBJECTIVE
  There is growing awareness that vitamin D sufficiency is required for overall optimal health. Most experts agree that 25-hydroxyvitamin D levels of at least 75 nmol/L, as sufficient vitamin D status. Our aim was to investigate the serum 25-hydroxyvitamin D concentration required in mid-October to ensure vitamin D sufficiency in early February, and to assess the rate of vitamin D insufficiency in both seasons.
  
  
  METHODS
  We measured serum 25-hydroxyvitamin D, parathormone, and other related biochemical parameters, in a sample of 28 professional football players homogeneous in factors influencing serum 25-hydroxyvitamin D concentration in a sunny area of southern Spain.
  
  
  RESULTS
  The serum 25-hydroxyvitamin D concentration of 122.7 nmol/L was required; 14.3% reached this level. Ninety-three percent had levels ≥75 nmol/L in mid-October, and 64% had levels <75 nmol/l in early February (χ(2) test, ρ = 0.001).
  
  
  CONCLUSIONS
  Despite the homogeneity in sunlight exposure and vitamin D intake few football players reached the level ensuring vitamin D sufficiency in mid-winter, and two thirds had vitamin D insufficiency in early February. Given our findings, it would be advisable to assess the vitamin D levels in early autumn, although additional studies are necessary.
authors.affiliation: Department of Medicine, Medical School, University of Seville, Internal Medicine Service, University Hospital Virgen Macarena, Avda. Doctor Fedriani s/n, Seville 41009, Spain. fgalan@us.es
authors.forename: Fernando
authors.initials: F
authors.lastname: Galan
authors.forename: Juan
authors.initials: J
authors.lastname: Ribas
authors.forename: Pilar María
authors.initials: PM
authors.lastname: Sánchez-Martinez
authors.forename: Tomás
authors.initials: T
authors.lastname: Calero
authors.forename: Antonio Barco
authors.initials: AB
authors.lastname: Sánchez
authors.forename: Adolfo
authors.initials: A
authors.lastname: Muñoz
mesh_terms: D000328:Adult; D056352:Athletes; D006801:Humans; D010281:Parathyroid Hormone / Q000097:blood; D012621:Seasons; D012916:Soccer; D013030:Spain / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology*; D044465:White People; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D