Mortality and cancer morbidity in a cohort of Swedish glassworkers

A cohort of 625 male, art glassworkers with employment of more than one month for some time between 1964 and 1985 was studied with regard to causes of death and cancer incidence. The number of total deaths was 97 versus 98.9 expected from national death rates and 82.9 expected from county death rates. A moderate increase in total cancer deaths was seen (26 observed cases vs 22.3 and 18.9 expected from national and county death rates, respectively) as also associated with duration of exposure. The excess number of cases was particularly noted for lung cancer, (6 observed cases vs 4.2 and 2.5 expected, respectively), colon cancer (4 observed cases vs 1.6 expected from both national and county death rates), cancer of the pharynx (2 observed cases vs 0.2 and 0.1 expected, respectively), and prostate (4 observed cases vs 3.0 and 2.4 expected, respectively). Most of these excesses occurred among men working in the foundry producing either heavy crystal glass or semicrystal glass, except for cancer of the prostate which occurred in the context of glass refinement. Excess risks for deaths from ischemic heart disease (39 observed cases vs 32.1 and 30.9 expected, respectively) and cerebrovascular disease (11 observed cases vs 7.3 and 6.5 expected, respectively) were also found, although with no clear relationship to duration of exposure. These latter risks occurred particularly among men working with the refinement of glass. Approximative correction for smoking habits resulted in increased risk estimates for lung cancer and ischemic heart disease, indicating a negative confounding effect from smoking in this material.