title: Occupational Class Groups as a Risk Factor for Gastrointestinal Cancer: A Case-Control Study.
abstract: Cancer has a high mortality rate in both developing and developed countries. 11%-15% of cancers are attributable to occupational risk factors.
  
  
  
  To determine if specific occupational classes, based on the International Standard for Classification of Occupations 2008 (ISCO-08), are risk factors for gastrointestinal (GI) cancer.
  
  
  
  In this case-control study, 834 cancer patients were interviewed by a single physician. Cases included patients with GI cancer. Age-matched controls were selected from non-GI cancer patients. Each year of working, up until 5 years before the diagnosis, was questioned and categorized by the ISCO classification.
  
  
  
  243 GI cancer cases and 243 non-GI cancer patients (486 in total) were studied. Working in ISCO class 8 (plant and machine operators, and assemblers) was significantly associated with higher risk of GI cancer (OR 1.63, 95% CI 1.05 to 2.52). Working in ISCO class 6 (skilled agricultural, forestry and fishery workers) and 9 (elementary occupations) were also associated with higher incidence of GI cancers.
  
  
  
  Working in ISCO classes of 8, 6, and 9, which are usually associated with low socio-economic status, can be considered a risk factor for GI cancers.
authors.affiliation: Occupational Medicine Research Center (OMRC), Iran University of Medical Sciences and Health Services (IUMS), Tehran, Iran.
authors.forename: Mashallah
authors.initials: M
authors.lastname: Aghilinejad
authors.affiliation: Occupational Medicine Research Center (OMRC), Iran University of Medical Sciences and Health Services (IUMS), Tehran, Iran.
authors.forename: Elahe
authors.initials: E
authors.lastname: Kabir-Mokamelkhah
authors.affiliation: Department of Occupational Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Imanizade
authors.affiliation: Department of Occupational Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran. drhosseindanesh@gmail.com.
authors.forename: Hossein
authors.initials: H
authors.lastname: Danesh
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009790:Occupations / Q000706:statistics & numerical data*; D012307:Risk Factors; D012923:Social Class
keywords: Classification; Epidemiology; Gastrointestinal tract; Neoplasms; Occupations; Risk factors