A population based case-control study was performed in Cracow, Poland, to determine the effect of
occupational air pollutants on various histological types of
lung cancer. Male cases and controls were identified from the Cracow Death Register. Information was obtained by mailed questionnaire from next of kin on smoking, occupational branch, occupational exposures, and other pertinent variables. Response rates were 73.5% in cases and 72.0% in controls. For cases that underwent a bronchial biopsy or surgical excision the histological diagnosis of the tumour was obtained from clinical records. The case group contained 343 subjects with
squamous cell carcinomas, 151 with
small cell carcinomas, and 106 with
adenocarcinomas. Twenty seven cases showed other histological types (
large cell carcinoma and not classifiable). Analysis was performed separately by histological type for occupational exposure variables adjusted for smoking. Long term exposure to
mineral dust and
metal dust (20 years or more) was found to be a significant risk factor for small cell and
squamous cell carcinoma. The effect was more pronounced if the analysis was restricted to those aged less than 70 years. The highest relative risk (RR) due to occupational exposures was found for
squamous cell carcinoma and exposure to
mineral dust for more than 20 years (RR = 2.45, 95% CI 1.43-4.19). The estimated effect of
mineral dust on
small cell carcinoma and
adenocarcinoma was smaller (RR = 2.29, 95% CI 1.16-4.53 and RR = 2.04, 95% CI 0.89-4.64 respectively). The effect of
metal dust and fumes seemed about the same for squamous and
small cell carcinoma. No specific agent could be identified as particularly important for a specific histological type; it rather seemed that the effects of the substances considered were similar for
lung cancers in general.