title: Investigating the patterns and determinants of seasonal variation in vitamin D status in Australian adults: the Seasonal D Cohort Study.
abstract: Vitamin D status generally varies seasonally with changing solar UVB radiation, time in the sun, amount of skin exposed, and, possibly, diet. The Seasonal D Study was designed to quantify the amplitude and phase of seasonal variation in the serum concentration of 25-hydroxyvitamin D, (25OH)D)) and identify the determinants of the amplitude and phase and those of inter-individual variability in seasonal pattern.
  
  
  
  The Seasonal D Study collected data 2-monthly for 12 months, including demographics, personal sun exposure using a diary and polysulphone dosimeters over 7 days, and blood for serum 25(OH)D concentration. The study recruited 333 adults aged 18-79 years living in Canberra (35°S, n = 168) and Brisbane (27°South, n = 165), Australia.
  
  
  
  We report the study design and cohort description for the Seasonal D Study. The study has collected a wealth of data to examine inter- and intra-individual seasonal variation in vitamin D status and serum 25(OH)D levels in Australian adults.
authors: National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia.
authors: Laura
authors: L
authors: King
authors: Duke Kunshan University, Kunshan, China.
authors: Keith
authors: K
authors: Dear
authors: College of Public Health, Medical & Veterinary Sciences, James Cook, University, Townsville, Australia.
authors: Simone L
authors: SL
authors: Harrison
authors: Menzies Research Institute Tasmania, University of Tasmania, Hobart, Australia.
authors: Ingrid
authors: I
authors: van der Mei
authors: Health Research Institute, University of the Sunshine Coast, Sippy Downs, Australia.|Queensland University of Technology, Brisbane, Australia.
authors: Alison M
authors: AM
authors: Brodie
authors: Health Research Institute, University of the Sunshine Coast, Sippy Downs, Australia.|Queensland University of Technology, Brisbane, Australia.
authors: Michael G
authors: MG
authors: Kimlin
authors: National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia. robyn.lucas@anu.edu.au.
authors: Robyn M
authors: RM
authors: Lucas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001315:Australia / Q000453:epidemiology; D002980:Climate; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012621:Seasons; D012867:Skin; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Adult; Australia; Cohort; Determinants; Season; Vitamin D