Cancer morbidity and quartz exposure in Swedish iron foundries

Occupational and Environmental Medicine, 2011

Annals of Occupational and Environmental Medicine, 2013

Background: Iron and steel foundry workers are exposed to various toxic and carcinogenic substances including crystalline silica, polycyclic aromatic hydrocarbons, and arsenic. Studies have been conducted on lung cancer in iron and steel founding workers and the concentration of crystalline silica in foundries; however, the concentration of crystalline silica and cases of lung cancer in a single foundry has never been reported in Korea. Therefore, the authors report two cases of lung cancer and concentration of crystalline silica by the X-ray diffraction method. Case presentation: A 55-year-old blasting and grinding worker who worked in a foundry for 33 years was diagnosed with lung cancer. Another 64-year-old forklift driver who worked in foundries for 39 years was also diagnosed with lung cancer. Shot blast operatives were exposed to the highest level of respirable quartz (0.412 mg/m 3), and a forklift driver was exposed to 0.223 mg/m 3. Conclusions: The lung cancer of the two workers is very likely due to occupationally related exposure given their occupational history, the level of exposure to crystalline silica, and epidemiologic evidence. Further studies on the concentration of crystalline silica in foundries and techniques to reduce the crystalline silica concentration are required.

2014

Annals of Occupational Hygiene, 2011

Background: Swedish foundries have a long tradition of legally required surveys in the workplace that, from the late 1960s onwards, included measurements of quartz. The availability of exposure data spanning almost 40 years presents a unique opportunity to study trends over that time and to evaluate the validity of exposure models based on data from shorter time spans. The aims of this study were (i) to investigate long-term trends in quartz exposure over time, (ii) using routinely collected quartz exposure measurements to develop a mathematical model that could predict both historical and current exposure patterns, and (iii) to validate this exposure model with up-to-date measurements from a targeted survey of the industry. Methods: Eleven foundries, representative of the Swedish iron foundry industry, were divided into three groups based on the size of the companies, i.e. the number of employees. A database containing 2333 quartz exposure measurements for 11 different job descriptions was used to create three models that covered time periods which reflected different work conditions and production processes: a historical model (1968-1989), a development model (1990-2004), and a validation model (2005-2006). A linear mixed model for repeated measurements was used to investigate trends over time. In all mixed models, time period, company size, and job title were included as fixed (categorical) determinants of exposure. The within-and between-worker variances were considered to be random effects. A linear regression analysis was performed to investigate agreement between the models. The average exposure was estimated for each combination of job title and company size. Results: A large reduction in exposure (51%) was seen between 1968 and 1974 and between 1975 and 1979 (28%). In later periods, quartz exposure was reduced by 8% per 5 years at best. In the first period, employees at smaller companies experienced $50% higher exposure levels than those at large companies, but these differences became much smaller in later years. The furnace and ladle repair job were associated with the highest exposure, with 3.9-8.0 times the average exposure compared to the lowest exposed group. Without adjusting for this autonomous trend over time, predicting early historical exposures using our development model resulted in a statistically significant regression coefficient of 2.42 (R 2 5 0.81), indicating an underestimation of historical exposure levels. Similar patterns were seen for other historical time periods. Comparing our development model with our validation model resulted in a statistically significant regression coefficient of 0.31, indicating an overestimation of current exposure levels. Conclusion: To investigate long-term trends in quartz exposure over time, overall linear trends can be determined by using mixed model analysis. To create individual exposure measures to predict historical exposures, it is necessary to consider factors such as the time period, type of job, type of company, and company size. The mixed model analysis showed systematic

American Journal of Epidemiology, 1998

An industry-wide mortality study on the association between lung cancer and occupational exposure to cobalt and tungsten carbide was carried out in the French hard-meta) industry. This case-control study was nested in the historical cohort of workers ever employed in this Industry's 10 facilities, most of which are located in eastern France. Workers were followed up from 1968 to 1991. Occupational exposure was assessed using a job-exposure matrix that provided semiquantitative scores for 320 job periods. These scores were significantly correlated with the levels of cobalt measured in 744 historical air samples. In this cohort, which comprised 5,777 males and 1,682 females, the death rate from lung cancer was significant (63 deaths, standardized mortality ratio = 1.30, 95% confidence interval (Cl) 1.00-1.66) when compared with national death rates. Sixty-one cases and 180 controls were included In the study. When the exposures during the last 10 years were ignored, a twofold lung cancer risk was observed among workers simultaneously exposed to cobalt and tungsten carbide (odds ratio (OR) = 1.93, 95% Cl 1.03-3.62) adjusted for other cobalt exposure (OR = 2.21, 95% Cl 0.99-4.90). The odds ratios increased with cumulative exposure (first quartile, OR = 1.00; second quartile, OR = 2.64; third quartile, OR = 2.59; fourth quartile, OR = 4.13) and, to a lesser degree, with duration of exposure (one decade, OR = 1.00; two decades, OR =1.61; three decades, OR = 2.77; four decades, OR = 2.03). Adjustments for smoking and for exposures to known or suspected carcinogens did not change the results, yet the odds ratio for smoking (3.38) was lower than expected, suggesting the possibility of some misclassification. Occupational risk was highest among smokers. This study supports the hypothesis that workers who manufacture hard metals have an increased mortality from lung cancer due to simultaneous exposure to cobalt and tungsten carbide. Am J Epidemiol 1998; 148:241-8.

American Journal of Industrial Medicine, 2003

Journal of occupational and environmental medicine, 2017

The cancer incidence was determined for 3713 workers from three plants from 1958 to 2011. The exposure measures were ever/never exposed, duration, cumulative, and mean cobalt concentrations. The incidence of all malignant neoplasms was increased at one plant, but standardized incidence ratio (SIR) was 0.96 for all workers. Lung cancer incidence was increased for all workers, SIR 1.38 (1.01 to 1.85). The lung cancer incidence was associated with shorter employment time and showed no exposure-response. There was decreased incidence for skin cancer. Increased lip cancer incidence found at one of the production plants might be related to diagnostic intensity. Lung cancer incidence showed no correlation to cobalt exposure based on internal comparison. The increased SIR for all workers might be associated with other factors.

Annals of Occupational Hygiene, 2002

Following the classification of quartz as a human carcinogen by the IARC, many standardsetting committees are currently trying to convert this hazard into their national or EU standards. Since human data to set a safe exposure limit for quartz are limited, we hypothesized that lung burden data on quartz in coal miners' lungs after lifetime exposure could be used to set a non-carcinogenic lung burden of quartz, and that this might be valid for other groups occupationally exposed to quartz. A review of data shows that lungs of coal miners with simple coal workers' pneumoconiosis (sCWP) typically contain up to 30 g of dust, and in one specific study lung burdens between 0.7 and 1.7 g of quartz were associated with macules only, and no sCWP. Assuming independent actions of coal and quartz and no clearance of quartz, and sCWP as a prerequisite for lung cancer due to quartz exposure in coal mine dust, a simple kinetic approach was applied. A no observed adverse effect level (NOAEL) for quartz of between 0.03 and 0.13 mg/m 3 (40 yr exposure) is derived, but it is concluded that more refined physiologically based pharmacokinetic modelling is needed for a better estimate, also including interindividual differences in lung clearance. Considering the independent effects of, and the well-known interaction between coal and quartz, these data could be important to other workplaces with usual mixed-dust exposure.

A questionnaire survey on the lifetime exposure to asbestos, quartz, and welding fumes among males aged 38-48 years (n=9,186) and females aged 40-43 years (n=3,495) in the county of Telemark, Norway was carried out in 1989-90. The overall response rate was 72%. A total of 42.9% of the males and 39.8% of the females were current smokers. Among the male responders, 32.5%, 16.4%, 21.1%, and 10.5% had been exposed at any time to asbestos, quartz, welding fumes, and stainless steel welding fumes respectively. The figures for exposure among female responders were negligible, i.e. 0.7%, 0.5%, 0.5%, and 0.1% respectively. The mean reported duration of exposure for the exposed subjects was 9.8 years for asbestos, 8.8 years for quartz, and 11.3 years for welding fumes. Subjects reporting any one of the exposure factors were more likely to be smokers. Exposure at the time of the survey was reported by 13.8% among the asbestos-exposed subjects, and by 22.7% and 34.4% among those exposed to quartz and welding fumes respectively. The need for primary intervention is emphasized. Smoking intervention in those already exposed to any of these determinants for lung cancer is also needed, as tobacco smoke may increase the lung cancer risk further.

Cancer Letters, 1986