title: Seasonal variation in Internet searches for vitamin D.
abstract: Internet search rates for "vitamin D" were explored using Google Trends. Search rates increased from 2004 until 2010 and thereafter displayed a seasonal pattern peaking in late winter. This knowledge could help guide the timing of public health interventions aimed at managing vitamin D deficiency.
  
  
  OBJECTIVE
  The Internet is an important source of health information. Analysis of Internet search activity rates can provide information on disease epidemiology, health related behaviors and public interest. We explored Internet search rates for vitamin D to determine whether this reflects the increasing scientific interest in this topic.
  
  
  METHODS
  Google Trends is a publically available tool that provides data on Internet searches using Google. Search activity for the term "vitamin D" from 1st January 2004 until 31st October 2016 was obtained. Comparison was made to other bone and nutrition related terms.
  
  
  RESULTS
  Worldwide, searches for "vitamin D" increased from 2004 until 2010 and thereafter a statistically significant (p < 0.001) seasonal pattern with a peak in February and nadir in August was observed. This seasonal pattern was evident for searches originating from both the USA (peak in February) and Australia (peak in August); p < 0.001 for both. Searches for the terms "osteoporosis", "rickets", "back pain" or "folic acid" did not display the increase observed for vitamin D or evidence of seasonal variation.
  
  
  CONCLUSIONS
  Public interest in vitamin D, as assessed by Internet search activity, did increase from 2004 to 2010, likely reflecting the growing scientific interest, but now displays a seasonal pattern with peak interest during late winter. This information could be used to guide public health approaches to managing vitamin D deficiency.
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK.|Paediatric Endocrinology, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Moon
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Curtis
authors.affiliation: Paediatric Endocrinology, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: Justin H
authors.initials: JH
authors.lastname: Davies
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK.|NIHR Southampton Nutrition Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK.|National Institute for Health Research (NIHR) Musculoskeletal Biomedical Research Unit, University of Oxford, Oxford, UK.
authors.forename: Cyrus
authors.initials: C
authors.lastname: Cooper
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK. nch@mrc.soton.ac.uk.|NIHR Southampton Nutrition Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK. nch@mrc.soton.ac.uk.
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Harvey
mesh_terms: D001315:Australia; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data*; D057386:Search Engine / Q000706:statistics & numerical data*; D012621:Seasons; D014481:United States; D014807:Vitamin D
chemical_list: D014807:Vitamin D
keywords: Epidemiology; Google Trends; Internet; Vitamin D