title: Chronic pain prevalence and associated factors in a segment of the population of São Paulo City.
abstract: A cross-sectional epidemiologic survey was performed to determine the prevalence of chronic pain (CP) and to identify associated factors in a random sample of persons 15 years or older from a segment of the population of São Paulo City, Brazil. A total of 1,108 eligible participants were randomly selected, and face-to-face interviews were performed with 826 individuals (74.5%) between December 2011 and February 2012. Chronic Pain Grade, Hospital Anxiety and Depression Scale, and EuroQol-5D were used to verify pain characteristics and the associated signs of psychological distress. A prevalence of 42% (95% confidence interval, 38.6-45.4) was observed for CP, and the participants with CP had an average pain intensity of 5.9 (standard deviation = 1.9) and a pain-related disability of 4.1 (standard deviation = 3.2) on a 0 to 10 scale. Persistent pain was present in 68.6% of those with CP, and 32.8% of the population sample had high-intensity or high-interference pain (Chronic Pain Grade II, III, and IV). Quality of life was significantly worse among the CP individuals. The following factors were independently associated with CP: female gender, age 30 years or older, ≤ 4 years of education, symptoms consistent with anxiety, and intense physical strain. Indicators of pain severity increased with pain grades.
  
  
  CONCLUSIONS
  CP is highly prevalent in the city of São Paulo and has a considerable impact on health-related quality of life. Demographic, socioeconomic, and psychological factors are independently associated with this condition.
authors.affiliation: University of São Paulo School of Medicine, São Paulo, Brazil. Electronic address: dayane_mcc@yahoo.com.br.
authors.forename: Dayane
authors.initials: D
authors.lastname: Maia Costa Cabral
authors.affiliation: University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Sawaya Botelho Bracher
authors.affiliation: University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Jidiene
authors.initials: J
authors.lastname: Dylese Prescatan Depintor
authors.affiliation: University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: Eluf-Neto
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D059350:Chronic Pain / Q000453:epidemiology* / Q000209:etiology / Q000523:psychology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D011788:Quality of Life; D012959:Socioeconomic Factors; D055815:Young Adult
keywords: Chronic pain; cross-sectional studies; disability; prevalence; quality of life