Occupation and risk of esophageal and gastric cardia adenocarcinoma

BACKGROUND: Adenocarcinomas of the esophagus and gastric cardia have risen dramatically in incidence over the past few decades, however, little research has been conducted on the occupational risk factors for these cancers. METHODS: In this population-based case-control study, lifetime job histories were compared between cases of esophageal adenocarcinoma (n = 283), gastric cardia adenocarcinoma (n = 259), and population controls (n = 689). Odds ratios (OR) and 95% confidence intervals (CI) for ever employment and by duration in various occupational and industrial categories were calculated using unconditional logistic regression. RESULTS: The risk of esophageal adenocarcinoma was elevated for persons ever employed in administrative support (OR = 1.5; 95%CI = 1.0-2.1); financial, insurance, and real estate (OR = 1.6; 95%CI = 1.0-2.4); and health services (OR = 2.2; 95%CI = 1.2-3.9). The risk of gastric cardia adenocarcinoma was increased among transportation workers (OR = 1.7; 95%CI = 1.1-2.6), as well as among carpenters (OR = 1.8; 95%CI = 0.9-3.9) and workers in the furniture manufacturing industry (OR = 2.4; 95%CI = 0.9-6.3). However, we observed few duration-response relations between length of employment in any category and cancer risk. CONCLUSIONS: This study revealed associations of esophageal adenocarcinoma with employment in administrative support, health services, and a category of financial, insurance, and real estate industries, and of gastric cardia adenocarcinoma with transportation and certain woodworking occupations. Some of these findings may be due to the play of chance associated with the multiple comparisons made in this study. Our results suggest that, overall, workplace exposures play a minor role in the etiology and upward trend of esophageal and gastric cardia adenocarcinomas.