Occupational Class Groups as a Risk Factor for Gastrointestinal Cancer: A Case-Control Study

BACKGROUND: Cancer has a high mortality rate in both developing and developed countries. 11%–15% of cancers are attributable to occupational risk factors. OBJECTIVE: 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. METHODS: 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 nonGI cancer patients. Each year of working, up until 5 years before the diagnosis, was questioned and categorized by the ISCO classification. RESULTS: 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. CONCLUSION: 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.