title: Reliability and validity of opiate use self-report in a population at high risk for esophageal cancer in Golestan, Iran.
abstract: OBJECTIVE
  To assess the reliability and validity of self-reported opium use in a rural Iranian population at high risk for esophageal cancer in preparation for a large cohort study.
  
  
  METHODS
  1,057 subjects ages 33 to 84 years were recruited from Gonbad city and three surrounding villages in Golestan province of Iran and completed a questionnaire and provided biological samples. The history and duration of using opium, smoking tobacco, chewing nass, and drinking alcohol were measured by questionnaire in the entire cohort. A subgroup of 130 people was reinterviewed after 2 months to assess reliability. Validity of the opium question was assessed by comparing the questionnaire responses with the presence of codeine and morphine in the urine of 150 selected subjects.
  
  
  RESULTS
  Self-reported opiate use is reliable and valid in this population. The reliability of ever opium use and duration of opium use had kappa's of 0.96 and 0.74, respectively. The validity of self-reported opium use was also high. Using urine codeine or morphine as the gold standard for use of opium, self-report had a sensitivity of 0.93 and a specificity of 0.89.
  
  
  CONCLUSIONS
  The self-reported use of opium can provide a reliable and valid measurement in this population and will be useful for studying associations between opium use and occurrence of esophageal cancer and other diseases.
authors.affiliation: Cancer Prevention Studies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. abnetc@mail.nih.gov
authors.forename: Christian C
authors.initials: CC
authors.lastname: Abnet
authors.forename: Mitra
authors.initials: M
authors.lastname: Saadatian-Elahi
authors.forename: Akram
authors.initials: A
authors.lastname: Pourshams
authors.forename: Paolo
authors.initials: P
authors.lastname: Boffetta
authors.forename: Ali
authors.initials: A
authors.lastname: Feizzadeh
authors.forename: Paul
authors.initials: P
authors.lastname: Brennan
authors.forename: Philip R
authors.initials: PR
authors.lastname: Taylor
authors.forename: Farin
authors.initials: F
authors.lastname: Kamangar
authors.forename: Sanford M
authors.initials: SM
authors.lastname: Dawsey
authors.forename: Reza
authors.initials: R
authors.lastname: Malekzadeh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects; D000701:Analgesics, Opioid / Q000633:toxicity / Q000652:urine; D003061:Codeine / Q000633:toxicity / Q000652:urine; D004938:Esophageal Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000633:toxicity / Q000652:urine; D018307:Neoplasms, Squamous Cell / Q000139:chemically induced / Q000453:epidemiology; D009293:Opioid-Related Disorders / Q000150:complications / Q000453:epidemiology* / Q000652:urine*; D009892:Opium / Q000633:toxicity / Q000652:urine; D010865:Pilot Projects; D012307:Risk Factors; D012423:Rural Health; D012650:Self Disclosure; D012907:Smoking / Q000009:adverse effects; D015813:Substance Abuse Detection; D011795:Surveys and Questionnaires
chemical_list: D000701:Analgesics, Opioid; D009020:Morphine; D009892:Opium; D003061:Codeine