Oesophageal cancer and occupational exposure to rubber: a nested case-control study

Findings for cancer of the oesophagus in the rubber industry are not consistent between studies, and derive from too few studies. Few studies were carried out to examine risks of oesophageal cancer in different departments and the confounding by non-occupational risk factors such as smoking, drinking, and economic status. In this paper these questions have been explored. Following a nested case-control study, the data were used of nine oesophageal cancer deaths during 1973-1995 and 36 controls matched for sex and age from the same cohort of a rubber plant workers. Oesophageal cancer risks for exposure to rubber were assessed, unadjusted and adjusted for non-occupational factors by conditional logistic regression. In grouped analysis, odds ratios (ORs) for oesophageal cancer were found to be 2.67 (95%CI=0.42,17.0) for milling, etc. workers and 1. 40 (95%CI=0.24,7.97) for building workers, who worked for one or more years. No excess risks were found in the remaining three departments. The models for continuous exposure variables indicated that a one-unit year change in the milling, etc. department was associated with a 4% increment in the OR. When adjusted for serum cholesterol level, the 6% increase (OR) was observed. Significant associations between risk for oesophageal cancer and specific exposures or processes within the rubber plant were not found. The slight excess risk for oesophageal cancer in the rubber plant may be related to exposure to dusts and solvents.