title: Seasonal trends in restless legs symptomatology: evidence from Internet search query data.
abstract: OBJECTIVE
  Patients with Willis-Ekbom disease (restless legs syndrome [RLS]) frequently report seasonal worsening of their symptoms; however, seasonal patterns in this disorder have not been systematically evaluated. The purpose of our investigation was to utilize Internet search query data to test the hypothesis that restless legs symptoms vary by season, with worsening in the summer months.
  
  
  METHODS
  Internet search query data were obtained from Google Trends. Monthly normalized search volume was determined for the term restless legs between January 2004 and December 2012. Using cosinor analysis, seasonal effects were tested for data from the United States, Australia, Germany, the United Kingdom, and Canada.
  
  
  RESULTS
  Cosinor analysis revealed statistically significant seasonal effects on search queries in the United States (P=.005), Australia (P=.00007), Germany (P=.00009), and the United Kingdom (P=.003), though a trend was present in the search data from Canada (P=.098). Search queries peaked in summer months in both northern (June and July) and southern (January) hemispheres. Search query volume increased by 24-40% during summer relative to winter months across all evaluated countries.
  
  
  CONCLUSIONS
  Evidence from Internet search queries across a wide range of dates and geographic areas suggested a seasonality of restless legs symptomatology with a peak in summer months. Our novel finding in RLS epidemiology needs to be confirmed in additional samples, and underlying mechanisms must be elucidated.
authors.affiliation: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States. Electronic address: dingram@uwhealth.org.
authors.forename: David G
authors.initials: DG
authors.lastname: Ingram
authors.forename: David T
authors.initials: DT
authors.lastname: Plante
mesh_terms: D001315:Australia / Q000453:epidemiology; D002170:Canada / Q000453:epidemiology; D005858:Germany / Q000453:epidemiology; D006801:Humans; D020407:Internet; D012148:Restless Legs Syndrome / Q000453:epidemiology*; D012307:Risk Factors; D012621:Seasons; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
keywords: Cosinor analysis; Google trends; Restless leg syndrome; Restless legs; Seasonality; Willis-Ekbom disease