A cohort of 736 male and 167 female workers of two anthophyllite mines in Finland was followed up through the Finnish Cancer Registry for cancer in 1953-91. Compared with the total cancer incidence of the east Finnish population, the men had a raised risk of total cancer (standardised incidence ratio (SIR) 1-7; 95% confidence interval (95% CI)1.4-1.9), mainly attributable to an excess in lung cancer (SIR 2-8; 95% CI 2.2-3.6).The risk of lung cancer was somewhat higher among workers classified as heavily exposed (SIR 3*2; 95% CI 2.4-4.1) than among those moderately exposed (SIR 2*3; 95% CI 1.5-3.6) and the risk increased with increasing smoking and with increasing time of work with exposure. There were four cases of mesothelioma v 0*1 expected, all in men who smoked and had had a long and heavy asbestos exposure. Among women, a non-significant excess in total cancer (SIR 1 5; 95% CI 0.9-2.4) was found in the subgroup with heavy exposure to asbestos. Anthophyllite asbestos seems to have high potency in the carcinogenesis of lung cancer and low potency in carcinogenesis of mesothelioma in comparison with the other types of asbestos.

Meurman, L. O., Kiviluoto, R., and Hakama, M. (1974). British Journal ofIndustrial Medicine, 31, 105-112. Mortality and morbidity among the working population of anthophyllite asbestos miners in Finland. A study has been made in Finland of the effects of anthophyllite asbestos on mortality and morbidity of 1 092 asbestos workers first employed at two mines between 1936 and 1969; 95 % of workers were traced, 248 of whom had died. A similar number of agesex-matched controls was selected from a township 60 km from the mines. The causes of death included an excess due to lung cancer and asbestosis, but cancers of the digestive system occurred in equal frequency, and neither the cases nor controls had any confirmed mesotheliomas. Assuming a multiplicative effect of asbestos and smoking, the relative risk of lung cancer was 17 for an asbestos worker who smokes in terms of a non-exposed nonsmoker. The corresponding figures were 12 for a smoker without asbestos exposure and 1-4 for an asbestos worker who did not smoke. More heavy smokers were found among the asbestos workers than among the controls. A threefold excess of dyspnoea and a twofold excess of cough were recorded for the asbestos workers compared with the controls after adjustment for smoking.

Four cases of mesothelioma in a cohort of 999 Finnish anthophyllite miners and millers are described. Three deaths were due to pleural mesothelioma and one to peritoneal mesothelioma among the total of 503 male deaths up to 1991. All four patients with mesothelioma had had long term (13 to 31 years) exposure in anthophyllite mining and milling. The latency time from the onset of employment until diagnosis was 39 to 58 years. All four patients were smokers or ex-smokers and had asbestosis. In three of the cases the pulmonary fibre concentration and fibre type were analysed by transmission electron microscopy. High concentrations (270 to 1100 million fibreslg dry tissue) of anthophyllite fibres were detected. The anthophyllite fibres were thicker and had lower aspect ratios than the values reported for crocidolite fibres retained in the lungs of patients with mesothelioma.

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