Lung cancer mortality among female mine workers exposed to silica

A mortality cohort study (1951-1988) was conducted on 526 female workers in two lead and zinc mines in southwestern Sardinia (Italy), 310 of whom had been exposed to silica. Women exposed to silica showed a nonsignificant 38% increase in the standardized mortality ratio (SMR) for nonmalignant respiratory diseases, which was highest and statistically significant among women at the mine with the highest exposure to silica (SMR = 217; 95% confidence interval [CI] = 104, 400; based on 10 observed and 4.6 expected deaths). Five deaths from lung cancer also occurred among those exposed to silica (SMR = 283; 95% CI = 91,660), but the excess was not related to the level or duration of exposure. No information was available concerning lifestyle risk factors in this cohort. However, smoking was quite rare among Sardinian women at the time cohort members worked, so it may be presumed that very few of them were smokers.