title: Hypovitaminosis D in British adults at age 45 y: nationwide cohort study of dietary and lifestyle predictors.
abstract: BACKGROUND
  Increased awareness of the importance of vitamin D to health has led to concerns about the prevalence of hypovitaminosis D in many parts of the world.
  
  
  OBJECTIVE
  We aimed to determine the prevalence of hypovitaminosis D in the white British population and to evaluate the influence of key dietary and lifestyle risk factors.
  
  
  METHODS
  We measured 25-hydroxyvitamin D [25(OH)D] in 7437 whites from the 1958 British birth cohort when they were 45 y old.
  
  
  RESULTS
  The prevalence of hypovitaminosis D was highest during the winter and spring, when 25(OH)D concentrations <25, <40, and <75 nmol/L were found in 15.5%, 46.6%, and 87.1% of participants, respectively; the proportions were 3.2%, 15.4%, and 60.9%, respectively, during the summer and fall. Men had higher 25(OH)D concentrations, on average, than did women during the summer and fall but not during the winter and spring (P = 0.006, likelihood ratio test for interaction). 25(OH)D concentrations were significantly higher in participants who used vitamin D supplements or oily fish than in those who did not (P < 0.0001 for both) but were not significantly higher in participants who consumed vitamin D-fortified margarine than in those who did not (P = 0.10). 25(OH)D concentrations <40 nmol/L were twice as likely in the obese as in the nonobese and in Scottish participants as in those from other parts of Great Britain (ie, England and Wales) (P < 0.0001 for both).
  
  
  CONCLUSIONS
  Prevalence of hypovitaminosis D in the general population was alarmingly high during the winter and spring, which warrants action at a population level rather than at a risk group level.
authors.affiliation: Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, London, United Kingdom. e.hypponen@ich.ucl.ac.uk
authors.forename: Elina
authors.initials: E
authors.lastname: Hyppönen
authors.forename: Chris
authors.initials: C
authors.lastname: Power
mesh_terms: D001827:Body Height; D001835:Body Weight; D015331:Cohort Studies; D005260:Female; D005843:Geography; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D018673:Nutrition Policy; D009765:Obesity / Q000453:epidemiology; D012621:Seasons; D012959:Socioeconomic Factors; D006113:United Kingdom; D014807:Vitamin D / Q000008:administration & dosage / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D014807:Vitamin D