title: An epidemiologic internet survey of fibromyalgia and chronic pain in Japan.
abstract: OBJECTIVE
  To determine the epidemiologic features and symptom characteristics of fibromyalgia (FM) in Japan, and compare them with those for other chronic pain (CP) diagnoses.
  
  
  METHODS
  An internet survey was conducted in June and July 2011. The questionnaire consisted of 111 questions, including assessments of the Japanese version of the 2010 American College of Rheumatology preliminary diagnostic criteria for FM, the Japanese Fibromyalgia Impact Questionnaire, and additional questions regarding pain and lifestyle.
  
  
  RESULTS
  The questionnaire was completed by 20,407 male and female respondents in all prefectures of Japan. Of the survey population, 2,524 respondents (12.4%) reported symptoms consistent with CP; of these, 425 (2.1%) reported symptoms consistent with FM. Among respondents with FM and CP, 61% and 53%, respectively, were women. Pain severity and Widespread Pain Index scores were significantly higher in respondents meeting the diagnostic criteria for FM than in those meeting the criteria for CP. In terms of symptom severity scores, the proportions of respondents reporting the 3 major symptoms as "highly applicable" and greater numbers of 41 somatic symptoms were higher among respondents with FM than among those with CP. The incidence of FM in the present survey was similar to that reported (1.7%) in a study of FM in Japan in 2003, despite the use of the newer, easier to use 2010 diagnostic criteria.
  
  
  CONCLUSIONS
  Because FM usually presents with more severe and more widely distributed pain, as well as more nonpainful symptoms than CP, our results suggest that FM is a different clinical phenotype of CP.
authors.affiliation: Kasumigaseki Medical Center for Rheumatic Disease, Toranomonkai Medical Corporation, Tokyo, Japan.
authors.forename: Ikuro
authors.initials: I
authors.lastname: Nakamura
authors.forename: Kenya
authors.initials: K
authors.lastname: Nishioka
authors.forename: Chie
authors.initials: C
authors.lastname: Usui
authors.forename: Kenichi
authors.initials: K
authors.lastname: Osada
authors.forename: Hisao
authors.initials: H
authors.lastname: Ichibayashi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Ishida
authors.forename: Dennis C
authors.initials: DC
authors.lastname: Turk
authors.forename: Yoshifuji
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Kusuki
authors.initials: K
authors.lastname: Nishioka
mesh_terms: D000328:Adult; D000368:Aged; D059350:Chronic Pain / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D016021:Epidemiologic Studies; D005260:Female; D005356:Fibromyalgia / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D006801:Humans; D020407:Internet; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012621:Seasons