Cancer in glass workers: a systematic review and meta-analysis.

PURPOSE: Due to a potential exposure to several definite or probable carcinogens, the IARC classified manufacturing of art glass, glass containers, and pressed ware as probably carcinogenic to humans in 1993 (Group 2A). Purpose of this study was to update the evidence from recently published scientific reports. METHODS: We searched for peer-reviewed articles published between 1993 and 2018 and combined result in terms of a meta-analysis. Overall, we considered twelve articles for a meta-analytic approach published after 1992. RESULTS: From a meta-analysis we derived a standardized incidence ratio (mSIR) and a standardized mortality ratio (mSMR) for lung cancer in men of 1.25 (95% CI 0.97-1.59) and 1.41 (95% CI 1.11-1.77), respectively. The estimated odds ratio (mOR) from five case-control studies was 1.25 (95% CI 0.90-1.73). Associated with an employment in glass factories, the estimated mSMR for larynx cancer was 2.38 (95% CI 1.23-4.16) based on two cohort studies; the mOR from four case-control studies was 1.35 (95% CI 0.73-2.52). Reports on elevated cancer risks at other sites were not consistent. CONCLUSIONS: Only few studies assessed cancer risk solely in glass workers. Gained evidence from more recent reports supports the IARC rating from 1993. Our combined results add limited evidence to a moderately elevated risk for cancer of the airways.

Quantitative crystalline silica exposure assessment for a historical cohort epidemiologic study in the German porcelain industry.

A time-dependent quantitative exposure assessment of silica exposure among nearly 18,000 German porcelain workers was conducted. Results will be used to evaluate exposure-response disease risks. Over 8000 historical industrial hygiene (IH) measurements with original sampling and analysis protocols from 1954-2006 were obtained from the German Berufs- genossenschaft der keramischen-und Glas-Industrie (BGGK) and used to construct a job exposure matrix (JEM). Early measurements from different devices were converted to modern gravimetric equivalent values. Conversion factors were derived from parallel historical measurements and new side-by-side measurements using historical and modern devices in laboratory dust tunnels and active workplace locations. Exposure values were summarized and smoothed using LOESS regression; estimates for early years were derived using backward extrapolation techniques. Employee work histories were merged with JEM values to determine cumulative crystalline silica exposures for cohort members. Average silica concentrations were derived for six primary similar exposure groups (SEGs) for 1938-2006. Over 40% of the cohort accumulated <0.5 mg; just over one-third accumulated >1 mg/m(3)-years. Nearly 5000 workers had cumulative crystalline silica estimates >1.5 mg/m(3)-years. Similar numbers of men and women fell into each cumulative exposure category, except for 1113 women and 1567 men in the highest category. Over half of those hired before 1960 accumulated >3 mg/m(3)-years crystalline silica compared with 4.9% of those hired after 1960. Among those ever working in the materials preparation area, half accumulated >3 mg/m(3)-year compared with 12% of those never working in this area. Quantitative respirable silica exposures were estimated for each member of this cohort, including employment periods for which sampling used now obsolete technologies. Although individual cumulative exposure estimates ranged from background to about 40 mg/m(3)-years, many of these estimates reflect long-term exposures near modern exposure limit values, allowing direct evaluation of lung cancer and silicosis risks near these limits without extrapolation. This quantitative exposure assessment is the largest to date in the porcelain industry.

Threshold value estimation for respirable quartz dust exposure and silicosis incidence among workers in the german porcelain industry.

OBJECTIVES: To estimate a threshold value for the respirable quartz dust concentration and silicosis incidence (1/1, ILO 1980/2000) in the German porcelain worker cohort. METHODS: Forty incident cases occurred among 17,144 workers. Estimation of the relationship to cumulative respirable quartz dust exposures by using Cox regression with restricted cubic splines (7 knots or less) and fractional polynomials (degrees 5 or less). Threshold estimates were obtained by subtracting candidate values from the time-dependent concentration data (setting the result to zero if negative) and recalculating cumulative exposure. RESULTS: Best threshold estimate was 0.25 mg/m (95% confidence interval: 0.15 to 0.30 mg/m). CONCLUSIONS: A concentration threshold for silicosis risk is plausible. A threshold Cox model fitted the data significantly better than a nonthreshold model, summarized the cohort information without a loss in extracted information and more simply than restricted cubic splines and fractional polynomials.

Respirable crystalline silica exposure-response evaluation of silicosis morbidity and lung cancer mortality in the German porcelain industry cohort.

OBJECTIVE: To quantify silicosis and lung cancer risks among porcelain workers occupationally exposed to respirable crystalline silica. METHODS: We reread historical radiographs to identify silicosis and estimated exposure on the basis of detailed work history and about 8000 industrial hygiene measurements. Cox proportional hazards models estimated risks by cumulative and average exposure. RESULTS: Adjusted silicosis hazards ratios were 5.3 (95% confidence interval [CI], 1.6 to 17.3); 7.3 (95% CI, 2.6 to 20.8); and 6.8 (95% CI, 3.0 to 15.3) for cumulative exposures >4 to 5; >5 to 6; and >6 mg/m-years, and 3.3 (95% CI, 0.8 to 14.7), 13.6 (95% CI, 4.2 to 44.4) and 23.2 (95% CI, 8.2 to 65.8) for average exposures >0.1 to 0.15; >0.15 to 0.2 and >0.2 mg/m, respectively. Exposure was not associated with any cause of death including lung cancer. CONCLUSIONS: Respirable crystalline silica exposure more than 4 mg/m-years (cumulative) or more than 0.15 mg/m (average) were strongly associated with silicosis, but unrelated to lung cancer risks.

Mortality in the German porcelain industry 1985-2005: first results of an epidemiological cohort study.

OBJECTIVES: To evaluate mortality due to lung cancer, silicosis, renal cancer, renal disease and other causes among German porcelain production workers potentially exposed to crystalline silica. METHODS: Seventeen thousand six hundred forty-four medical surveillance participants (1985-1987) were followed through 2005 for mortality. Cause-specific Standardized Mortality Ratios (SMR) and 95% confidence intervals were estimated. RESULTS: Women (SMR = 0.85; 95% CI = 0.78 to 0.93), but not men, demonstrated a healthy worker effect. Lung and renal cancers, and renal disease (non-malignant renal disease) were not associated with employment or exposure surrogates. Mortality was increased from silicosis (SMR = 7.20; 95% CI = 2.32 to 16.8) liver (SMR = 1.99; 95% CI = 1.29 to 2.93) and pancreatic (SMR = 1.71; 95% CI = 1.18 to 2.41) cancers among men, and diabetes among women (SMR = 1.74; 95% CI = 1.07 to 2.65). A sub-cohort of Bavarian workers generated similar but generally higher SMRs. CONCLUSIONS: Silicosis mortality was increased in this, among the largest studies to date. However, associations previously observed between crystalline silica exposure and renal or lung cancers or non-malignant renal disease were not supported.

Lung cancer among rock and slag wool production workers.

BACKGROUND: Previous cohort studies have found an elevated risk of lung cancer among rock and slag wool (RSW) production workers. The aim of the present study was to investigate the risk of lung cancer associated with exposure to RSW while controlling for other occupational exposures and tobacco smoking. METHODS: Since 1971, a total of 196 lung cancer cases occurred among men who worked in seven plants in Denmark, Norway, Sweden, and Germany, with start of production between 1937 and 1950. We obtained information on occupational history and extra-occupational factors from either the subject or the next of kin for 133 cases and 513 matched controls. We assessed occupational exposure on the basis of interview data combined with information from expert panels set up in each factory. RESULTS: For cumulative exposure to RSW assessed with a 15-year lag, the smoking-adjusted odds ratios in the second, third, and fourth quartiles of exposure were 1.3 (95% confidence interval [CI] = 0.7-2.3), 1.0 (CI = 0.5-1.9), and 0.7 (CI = 0.3-1.3). Similar results were obtained when we included only those workers employed for more than 1 year, when we included other indicators of RSW exposure, and after control for co-exposures. CONCLUSIONS: This study provides no evidence of a carcinogenic effect on the lung of rock and slag wool under exposure circumstances in the production industry during the last four to five decades.