Plasma vitamin concentrations and incidence of mesothelioma and lung cancer in individuals exposed to crocidolite at Wittenoom, Western Australia.

ABSTRACT

Increased rates of death from asbestos-related diseases have been reported in former workers and residents exposed to crocidolite (blue asbestos) at Wittenoom (Western Australia). The relationships between plasma concentrations of retinol, carotene and vitamin E and incidence of mesothelioma and lung cancer in a cohort of people from this town were examined. The relationships were evaluated by survival analyses using data obtained at the first visit, at each visit and with the rate of change of each vitamin during the period of follow-up. Of 1953 study participants, 65 developed mesothelioma during the follow-up, and 47 developed lung cancer. A lower incidence of mesothelioma was related to plasma concentrations of retinol at the first visit [hazard ratio (HR)=0.63, 95% confidence interval=0.41-0.99], and to measurements at each visit (HR=0.71, 95% confidence interval=0.50-1.00). Plasma carotene concentrations at the first measurement, but not during the follow-up period, were associated with lower incidence of lung cancer in men and in workers. No significant associations were found between carotene concentrations and incidence of mesothelioma. Vitamin E concentrations were not significantly associated with mesothelioma or lung cancer incidence. These findings suggest that people with chronically low plasma levels of retinol have increased risk of developing mesothelioma and lung cancer.