Mortality in a Chinese rubber factory: A prospective cohort study

Abstract

To determine the specific causes of mortality in the rubber industry with emphasis on the associations between cancer sites, ischemic heart, and cerebrovascular disorders and work places, A cohort of 1598 rubber workers (934 men, 664 women) were followed up for mortality from 1 January 1973 to 31 December 1997. Work histories of cohort members at the relevant work place were coded and computed by the factory personnel concerned and the record incorporated all job changes with relevant years. Standardized mortality ratios (SMRs) and 95% confidence intervals (95% Cls), controlling for age and calendar year and stratified by work area (employment in respective work areas for at least one year) were calculated from the reference rate. Significant increases in mortality were found for lung cancer among male workers in the curing department (16 deaths, 6.7 expected, SMR 2.39), liver cancer among male workers in the rubber overshoes department (2 deaths, 0.2 expected, SMR 10.00), cerebrovascular disorders among male workers in the rubber overshoes department (4 deaths, 1.0 expected, SMR 4.00), and cerebrovascular disorders among female workers in the mixing and milling department (7 deaths, 2.0 expected, SMR 3.50). Mortality from the remaining cancers was not substantially increased in any of the work departments. Mortality from several diseases was associated with specific work departments. Some of these associations have been reported previously and they may be causally related to occupational exposure in this industry, for example, lung cancer and the curing department. The study also found new risks, such as a possible increase in cerebrovascular disorders.