title: A nationwide population-based study of tension-type headache in Brazil.
abstract: OBJECTIVE
  To estimate the 1-year prevalence of tension-type headache (TTH) and the degree of the association of TTH with some sociodemographic characteristics of a representative sample of the adult population of Brazil.
  
  
  METHODS
  This was an observational, cross-sectional, population-based study. We conducted telephone interviews on 3848 people, aged 18-79 years, randomly selected from the 27 states of Brazil. Trained lay interviewers administered the structured questionnaire. It included questions about the sociodemographic characteristics of the population, as well as questions about headache. The degree of the association was calculated through prevalence ratios, adjusted with Poisson regression by gender, age, years of education, marital status, household income, job status, body mass index (BMI), and physical exercise.
  
  
  RESULTS
  The estimated 1-year gender- and-age-adjusted prevalence of TTH was 13.0% (95% CI: 11.8-14.2%); 15.4% in males and 9.5% in females. The prevalence of probable TTH was 22.6% (95% CI: 21.1-24.1%). Most (86.2%) subjects reported episodic TTH; 6.4% had chronic TTH. The prevalence was higher at 18-29 years of age (16.2%). TTH was 1.6 times more prevalent in men, and 1.54 times more in subjects with more than 11 years of education. There was no significant association of TTH with marital or job status, household income, BMI, and physical activity.
  
  
  CONCLUSIONS
  This is the first nationwide epidemiological study of TTH in Brazil. The overall prevalence of TTH in Brazil is low, at 13%. TTH is significantly more prevalent in males and subjects with higher education level.
authors.affiliation: Universidade Federal de Santa Catarina, Neurology Department, Florianopolis, Brazil.
authors.forename: Luiz P
authors.initials: LP
authors.lastname: Queiroz
authors.forename: Mario F P
authors.initials: MF
authors.lastname: Peres
authors.forename: Elcio J
authors.initials: EJ
authors.lastname: Piovesan
authors.forename: Fernando
authors.initials: F
authors.lastname: Kowacs
authors.forename: Marcello C
authors.initials: MC
authors.lastname: Ciciarelli
authors.forename: Jano A
authors.initials: JA
authors.lastname: Souza
authors.forename: Eliova
authors.initials: E
authors.lastname: Zukerman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012959:Socioeconomic Factors; D018781:Tension-Type Headache / Q000453:epidemiology*; D055815:Young Adult