Cancer incidence was analysed in a retrospective cohort of 3710 male Swedish smelter workers between 1958 and 1982 using a record linkage with the Swedish Cancer Register. During this period 467 cancers were registered in the cohort. An excess incidence of total cancer of about 30% was shown relative to general and local populations mainly due to 120 respiratory cancers. Excess SMRs for all cancer and respiratory cancer were highly significant. Trends in the incidence of cancer were studied using moving five year calendar periods. A decreasing rate of lung cancer was found during 1976-80 for both mortality and incidence. Incidence figures for two more years show a continued decreasing trend. This is validated by an analysis of different employment cohorts, taking latency into account, showing that the later the date of first employment the lower the incidence of cancer, especially for lung cancer.
A cohort study of the mortality experience (1950-1984) of 1,772 Newfoundland underground fluorspar miners occupationally exposed to high levels of radon daughters (mean dose = 382.8 working levels months) has been conducted. Observed numbers of cancers of the lung, salivary gland, and buccal cavity and pharynx were significantly elevated among these miners. A highly significant relation was noted between radon daughter exposure and risk of dying of lung cancer; the small numbers of salivary gland (n = 2) and buccal cavity and pharynx (n = 6) cancers precluded meaningful analysis of dose response. Attributable and relative risk coefficients for lung cancer were estimated as 6.3 deaths per working level month per million person-years and 0.9% per working level month, respectively. Relative risk coefficients were highest for those first exposed before age 20 years. Cigarette smokers had relative and attributable risk coefficients comparable to those of nonsmokers. Relative risks fell sharply with age, whereas attributable risks were lowest in the youngest and oldest age groups. The results suggest that efforts to raise existing occupational exposure standards may be inappropriate.
A retrospective cohort study was undertaken to investigate the cancer mortality of granite workers. The study comprised 1026 workers who took up such work between 1940 and 1971. The number of person-years was 23,434, and the number of deaths was 296. During the total follow-up period, 59 tumours were observed as compared with 54.4 expected. An excess mortality from tumours was observed in workers followed up for 20 years or more. Of the 59 tumours, 31 were lung cancers (expected 19.9), and 18 gastrointestinal cancers (expected 11.6), nine of which were stomach cancers (expected 7.1). Mortality from lung cancer was excessive for workers followed up for at least 15 years (28 observed, 12.7 expected). The results indicate that granite exposure per se may be an etiological factor in the initiation or promotion of malignant neoplasms.
We conducted a study to determine the types and causes of serious injuries to young workers (YW) (ages 14-24) in British Columbia.
The WorkSafeBC database from 2000 to 2005 was searched for all claims, all non-health-care-only (NHCO) injuries and all serious injury claims involving workers aged 14-24.
Of 384,250 NHCO claims, 15.6% were for YW, not significantly different from the British Columbia workforce (P > 0.75). Of the 5217 serious injuries, 9.8% (including 40 fatalities) were to YW-455 males and 56 females, significantly different from the workforce (50% male) ((2) = 259.8; df = 1; P
A collaborative study has been performed in order to detect cases of pleural mesothelioma diagnosed or treated in Italy in the years 1984-88. Cases have been notified to ISS by 88 centres (clinics of thoracic surgery and respiratory diseases, oncologic centres, institutes of pathology), active in 14 Italian regions. Altogether, 575 cases (415 males and 160 females) have been included in the study. Information on occupation and/or on non occupational exposure to asbestos was available for 65% of the subjects, and the occurrence of definite or possible exposure to asbestos was estimated for 58% of them.
Mortality rates of two cohorts of asbestos friction product (FP) workers were studied in comparison with the population of the adjoining towns over periods of 20 and 40 years respectively. The second cohort was subdivided into 3 subcohorts exposed to chrysotile asbestos (CA), vulcanization and/or polymerization vapours and gases (VPGV) and asbestos bakelite (AB) or asbestos rubber (AR) dusts. In the first cohort no deaths from lung cancer were recorded, even though the total tumour mortality was higher than in the general population. In the second cohort an excess tumour mortality was observed in the first subcohort for stomach cancer only. In the other two subcohorts the expected rates were higher for all the tumour sites. Following intraperitoneal injection of CA, AB and AR dusts, malignant tumours developed in 31.5% of the rats which received CA, and in about 10% of the rats which were injected with AB and AR dusts. Also, the mean longevity of CA-treated animals was significantly lower than in the other two groups. Thus, the carcinogenic risk was real in the group of FP production workers with significant CA exposure only.