title: Chronic headache and comorbidities: a two-phase, population-based, cross-sectional study.
abstract: BACKGROUND
  Studies using resources of a public family health program to estimate the prevalence of chronic daily headaches (CDH) are lacking.
  
  
  OBJECTIVE
  To estimate the 1-year prevalence of CDH, as well as the presence of associated psychiatric and temporomandibular disorders (TMD) comorbidities, on the entire population of a city representative of the rural area of Brazil.
  
  
  METHODS
  This was a cross-sectional, population-based, 2-phase study. In the first phase, health agents interviewed all individuals older than 10 years, in a rural area of Brazil. In the second stage, all individuals who reported headaches on 4 or more days per week were then evaluated by a multidisciplinary team. CDH were classified according to the second edition of the International Classification of Headache Disorders (ICHD-2). Medication overuse headache was diagnosed, as per the ICHD-2, after detoxification trials. Psychiatric comorbidities and TMD were diagnosed based on the DSM-IV and on the Research Diagnostic Criteria for Temporomandibular Disorders criteria, respectively.
  
  
  RESULTS
  A total of 1631 subjects participated in the direct interviews. Of them, 57 (3.6%) had CDH. Chronic migraine was the most common of the CDH (21, 36.8%). Chronic tension-type headache (10, 17.5%), medication overuse headache (13, 22.8%) and probable medication overuse headache (10, 17.5%) were also common. Psychiatric disorders were observed in 38 (67.3%) of the CDH subjects. TMD were seen in 33 (58.1)% of them.
  
  
  CONCLUSIONS
  The prevalence of CDH in the rural area of Brazil is similar to what has been reported in previous studies. A significant proportion of them have psychiatric comorbidities and/or TMD. In this sample, comorbidities were as frequent as reported in convenience samples from tertiary headache centers.
authors.affiliation: UFMG - Headache Clinic, Belo Horizonte, Brazil.
authors.forename: Ariovaldo
authors.initials: A
authors.lastname: da Silva
authors.forename: Esther Coelho
authors.initials: EC
authors.lastname: Costa
authors.forename: João Bosco
authors.initials: JB
authors.lastname: Gomes
authors.forename: Frederico Motta
authors.initials: FM
authors.lastname: Leite
authors.forename: Rodrigo Santiago
authors.initials: RS
authors.lastname: Gomez
authors.forename: Luiz Paulo
authors.initials: LP
authors.lastname: Vasconcelos
authors.forename: Abouch
authors.initials: A
authors.lastname: Krymchantowski
authors.forename: Pedro
authors.initials: P
authors.lastname: Moreira
authors.forename: Antonio Lucio
authors.initials: AL
authors.lastname: Teixeira
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil; D002648:Child; D002908:Chronic Disease; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D020773:Headache Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D055815:Young Adult