title: Changes of 25-OH-Vitamin D during Overwintering at the German Antarctic Stations Neumayer II and III.
abstract: OBJECTIVE
  Humans in Antarctica face different environmental challenges, such as low ultra-violet radiation, which is crucial for vitamin D production in humans. Therefore we assessed changes in 25-OH-vitamin D serum concentration during 13 months of overwintering at the German Stations Neumayer II and III (2007-2012). We hypothesized that (i) 25-OH-vitamin D serum concentration would significantly decrease, (ii) changes would be affected by age, gender, baseline (i.e. pre-overwintering) fat mass, baseline 25-OH-vitamin D serum concentration, and station residence, and (iii) our results would not differ from similar previous studies in comparable high latitudes.
  
  
  METHODS
  25-OH-vitamin D serum concentrations were determined before, after, and monthly during the campaigns from venous blood samples of n = 43 participants (28 men, 15 women). Baseline fat mass was determined via bio impedance analysis and body plethysmography. Data were analyzed for change over time, dependency on independent parameters, and after categorization for sufficiency (>50nmol/l), insufficiency (25-50nmol/l), and deficiency (<25nmol/l). Results were compared with data from similar previous studies.
  
  
  RESULTS
  We found a significant decrease of 25-OH-vitamin D with dependency on month. Age, gender, fat mass, and station residence had no influence. Only baseline 25-OH-vitamin D serum concentrations significantly affected subsequent 25-OH-vitamin D values.
  
  
  CONCLUSIONS
  Overwinterings at the Antarctic German research stations Neumayer II and III are associated with a decrease in 25-OH-vitamin D serum concentrations, unaffected by age, gender, baseline fat mass, and station residence. Higher baseline vitamin D serum concentrations might protect from subsequent deficiencies. Residence at the Neumayer Stations may lead to lower vitamin D serum concentrations than found in other comparable high latitudes.
authors.affiliation: Center for Space Medicine and Extreme Environments Berlin, Institute for Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Steinach
authors.affiliation: Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Kohlberg
authors.affiliation: Center for Space Medicine and Extreme Environments Berlin, Institute for Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.|Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.
authors.forename: Martina Anna
authors.initials: MA
authors.lastname: Maggioni
authors.affiliation: Center for Space Medicine and Extreme Environments Berlin, Institute for Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Mendt
authors.affiliation: Center for Space Medicine and Extreme Environments Berlin, Institute for Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Opatz
authors.affiliation: Center for Space Medicine and Extreme Environments Berlin, Institute for Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Stahn
authors.affiliation: Center for Space Medicine and Extreme Environments Berlin, Institute for Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Josefine
authors.initials: J
authors.lastname: Tiedemann
authors.affiliation: Center for Space Medicine and Extreme Environments Berlin, Institute for Physiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Hanns-Christian
authors.initials: HC
authors.lastname: Gunga
mesh_terms: D000328:Adult; D000367:Age Factors; D000864:Antarctic Regions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012621:Seasons; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D