Nonmalignant mortality among workers in six Norwegian aluminum plants

Annual decline in forced expiratory volume is steeper in aluminum potroom workers than in workers without exposure to potroom fumes

Background

Aluminum potroom exposure is associated with increased mortality of COPD but the association between potroom exposure and annual decline in lung function is unknown. We have measured lung volumes annually using spirometry from 1986 to 1996. The objective was to compare annual decline in forced expiratory volume in 1 s (dFEV1) and forced vital capacity (dFVC).

Methods

The number of aluminum potroom workers was 4,546 (81% males) and the number of workers in the reference group was 651 (76% males). The number of spirometries in the index group and the references were 24,060 and 2,243, respectively.

Results

After adjustment for confounders, the difference in dFEV1 and dFVC between the index and reference groups were 13.5 (P < 0.001) and −8.0 (P = 0.060) ml/year.

Conclusion

Aluminum potroom operators have increased annual decline in FEV1 relative to a comparable group with non‐exposure to potroom fumes and gases. Am. J. Ind. Med. 59:322–329, 2016. © 2016 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc.

Construction of a Job Exposure Matrix to Dust, Fluoride, and Polycyclic Aromatic Hydrocarbons in the Norwegian Aluminum Industry using Prediction Models

BACKGROUND

The Norwegian aluminum industry developed and implemented a protocol for prospective monitoring of employees' exposure using personal samplers. We analyzed these data to develop prediction lines to construct a job exposure matrix (JEM) for the period 1986-1995.

METHODS

The protocol for personal monitoring of exposure was implemented in all seven Norwegian aluminum plants in 1986 and continued until 1995. Personal samplers were used to collect total dust, fluorides, and total polycyclic aromatic hydrocarbons (PAH). In addition, exposure could be categorized according to process, i.e. prebake, Søderberg, and 'other'. We constructed four-dimensional JEMs characterized by: Plant, Job descriptor, Process, and Year. Totally 8074, 6734, and 3524 measurements were available for dust, fluorides, and PAH, respectively. The data were analyzed using linear mixed models with two-way interactions. The models were assessed using the Akaike criterion (AIC) and unadjusted R (2). The significance level was set to 10% (two-sided) for retaining variables in the model.

RESULTS

In 1986, the geometric mean (95% confidence interval in parentheses) for total dust, total fluorides, and PAH were 3.18 (0.46-22.2) mg m(-3), 0.58 (0.085-4.00) mg m(-3), and 33.9 (2.3-504) µg m(-3), respectively. During 10 years of follow-up, the exposure to total dust, fluorides, and PAH decreased by 9.2, 11.7, and 14.9% per year, respectively. Each model encompassed from 49 to 72 significant components of the interaction terms. The interaction components were at least as important as the main effects, and 65 to 91% of the significant components of the interaction terms were time-dependent.

CONCLUSION

Our prediction models indicated that exposures were highly time-dependent. We expect that the time-dependent changes in exposure are of major importance for longitudinal studies of health effects in the aluminum industry.

Asthma caused by potassium aluminium tetrafluoride: a case series

The objective of this study is to describe a case-series of potassium aluminium tetrafluoride (KAlF(4))-induced occupational asthma (OA) and/or occupational rhinitis (OR). The study involves five patients from a heat-exchanger production line who were examined (including specific inhalation challenge tests) for suspected OA and/or OR caused by a flux containing almost 100% KAlF(4) - with fluorides' workplace air concentrations ranging between 1.7 and 2.8 mg/m(3). No subject had a previous history of asthma. All five patients had a positive specific challenge test (three patients were diagnosed with OA alone, one with OR and one with both OR and OA). At the follow-up visit, after three years on average, all patients needed permanent corticosteroid therapy (four topical, one oral). After elimination from the exposure, only one of the observed subjects gave an indication of an improvement, two subjects stabilized and two worsened. Our case series focuses on the correlation between patients' exposure to fluorides in air-conditioner production and the subsequent occurrence of OR/OA. Currently, it is uncertain whether these OR/OA were caused by hypersensitivity or irritation.

Respiratory disorders in aluminum smelter workers

Objectives:

Summarizing the knowledge status, including the morphology, possible etiological factors, and clinical expression of aluminum potroom asthma and chronic obstructive pulmonary disease related to aluminum potroom exposure.

Methods:

A review of the literature from the last two decades as it appears in PubMed.

Results:

There is substantial evidence for the existence of potroom asthma, although the incidence seems to decline over the last 10 years. Increased mortality from chronic obstructive pulmonary disease and longitudinal decline in forced expiratory volume in the first second of expiration has been shown in aluminum potroom workers. Morphological manifestations in bronchial biopsies and the inflammatory markers NO and eosinophils in airway tissue and blood are consistent with asthma in general. The causative agent(s) is (are) not known.

Conclusions:

Reduction of exposure and cessation of smoking seem to be the major preventive measures to avoid respiratory disorders in the aluminum industry.

Medical follow-up for workers exposed to bladder carcinogens: the French evidence-based and pragmatic statement

BACKGROUND

The aim of this work was to establish recommendations for the medical follow-up of workers currently or previously exposed to carcinogenic substances for the bladder.

METHODS

A critical synthesis of the literature was conducted. Sectors of activity where workers are or were exposed to carcinogenic substances for the bladder were listed and classified according to the level of bladder cancer risk. Performances of techniques available for the targeted screening of bladder cancer were analysed, including a simulation of results among high-risk populations in France.

RESULTS

The risk level for the professional group and the latency period between the start of exposure and the natural history of the disease were selected to define a targeted screening protocol. The NMP22BC test, exclusive haematuria testing, and combinations of urine cytology with, respectively, the NMP22BC test and haematuria test, generated an extremely high proportion of false positive results.

CONCLUSION

Urine cytology is the test that offers the best specificity. Although poor for all bladder cancer stages and grades combined, its sensitivity is better for high grades, which require early diagnosis since late-stage cancers are of very poor prognosis. These results suggest that urine cytology is currently the only technique suitable for proposal within the context of a first line targeted screening strategy for occupational bladder cancer. An algorithm summarising the recommended medical follow-up for workers currently or previously exposed to carcinogenic substances for the bladder is proposed, based on the level of risk of bladder cancer.

Chronic and acute effects of coal tar pitch exposure and cardiopulmonary mortality among aluminum smelter workers

Air pollution causes several adverse cardiovascular and respiratory effects. In occupational studies, where levels of particulate matter and polycyclic aromatic hydrocarbons (PAHs) are higher, the evidence is inconsistent. The effects of acute and chronic PAH exposure on cardiopulmonary mortality were examined within a Kitimat, Canada, aluminum smelter cohort (n = 7,026) linked to a national mortality database (1957-1999). No standardized mortality ratio was significantly elevated compared with the province's population. Smoking-adjusted internal comparisons were conducted using Cox regression for male subjects (n = 6,423). Ischemic heart disease (IHD) mortality (n = 281) was associated with cumulative benzo[a]pyrene (B(a)P) exposure (hazard ratio = 1.62, 95% confidence interval: 1.06, 2.46) in the highest category. A monotonic but nonsignificant trend was observed with chronic B(a)P exposure and acute myocardial infarction (n = 184). When follow-up was restricted to active employment, the hazard ratio for IHD was 2.39 (95% confidence interval: 0.95, 6.05) in the highest cumulative B(a)P category. The stronger associations observed during employment suggest that risk may not persist after exposure cessation. No associations with recent or current exposure were observed. IHD was associated with chronic (but not current) PAH exposure in a high-exposure occupational setting. Given the widespread workplace exposure to PAHs and heart disease's high prevalence, even modest associations produce a high burden.

Relationship between cardiopulmonary mortality and cancer risk and quantitative exposure to polycyclic aromatic hydrocarbons, fluorides, and dust in two prebake aluminum smelters

OBJECTIVES

We examined the risk of mortality and cancer incidence with quantitative exposure to benzene-soluble fraction (BSF), benzo(a)pyrene (BaP), fluoride, and inhalable dust in two Australian prebake smelters.

METHODS

A total of 4,316 male smelter workers were linked to mortality and cancer incidence registries and followed from 1983 through 2002 (mean follow-up: 15.9 years, maximum: 20 years). Internal comparisons using Poisson regression were undertaken based on quantitative exposure levels.

RESULTS

Smoking-adjusted, monotonic relationships were observed between respiratory cancer and cumulative inhalable dust exposure (trend p = 0.1), cumulative fluoride exposure (p = 0.1), and cumulative BaP exposure (p = 0.2). The exposure-response trends were stronger when examined across the exposed categories (BaP p = 0.1; inhalable dust p = 0.04). A monotonic, but not statistically significant trend was observed between cumulative BaP exposure and stomach cancer (n = 14). Bladder cancer was not associated with BaP or BSF exposure. No other cancer and no mortality outcomes were associated with these smelter exposures.

CONCLUSIONS

The carcinogenicity of Söderberg smelter exposures is well established; in these prebake smelters we observed an association between smelter exposures and respiratory cancer, but not bladder cancer. The exploratory finding for stomach cancer needs confirmation. These results are preliminary due to the young cohort and short follow-up time.

Occupational causes of chronic obstructive pulmonary disease

The relation between Chronic Obstructive Pulmonary Disease (COPD, including chronic bronchitis and emphysema (CBE), and exposure to coal dust is well established. This paper reviews the evidence relating to other occupational causes of COPD, including industries associated with exposure to fumes, chemical substances, and dusts. A review of key literature has been carried out with a focus on the magnitude of risks and levels of exposure causing disabling health effects. The literature suggests that elevated risks of developing COPD are clearly associated with several occupations, with risk estimates being high in some, even after taking into account the effect of confounders, such as smoking. Of particular concern are agricultural workers who can be exposed to a variety of gases and organic dusts, among whom CBE is clearly elevated, particularly for pig farmers and exposure to endotoxins, with an increased annual decline in lung function. Similarly, cotton textile workers are exposed to a mixture of substances affecting development of atopy, byssinosis, and CBE, and across-shift and long-term decline in lung function. Atopy also has an important role in the development of COPD in flour mill workers and bakers, with those sensitized to bakery allergens having a greater lung function decline than non-sensitized individuals. Welding processes involve a range of potential chemical, physical and radiation hazards. The average reduction in FEV1 associated with welding fumes is similar to that associated with smoking. Challenges in assessing the evidence include variation in diagnostic methods; concurrent exposure to cigarette smoke (direct or second-hand) and multiple work-place irritants; healthy worker selection/survivor effects; poor exposure definition. Raising awareness of occupational causes of COPD among employers, employees, and health service professionals is important.

Fluoride poisoning: a puzzle with hidden pieces

Key industry data regarding harm from chronically inhaled fluoride have been unavailable publicly for decades. Recent unveiling of unpublished reports reveals three examples of data mishandling that disguised the need for more stringent occupational standards for particulate and gaseous fluorides and fluorine. Injury reports from workers handling chemicals show that unjustifiable reductions of injury and disability numbers in the process of publication shifted concern from respiratory to mineralized tissue damage. Selective editing and data omissions allowed bias that fluoride reduces caries without detrimental effects. Finally, industry's failure to publish an important industry-funded laboratory study buried knowledge of low thresholds for fluoride-induced lung disease. Data from that study are presented to clarify the dose- and duration-dependent changes caused by chronic inhalation of calcium fluoride.

Health effects of occupational exposure to fluorine and its compounds in a small-scale enterprise

A 7-yr study was conducted to evaluate the respiratory effects of fluorine compounds on exposed workers in a small-scale enamel enterprise. Air monitoring was done and 75 pairs, exposed and non-exposed workers were examined. The applied tests were: an epidemiological questionnaire, the bronchitis record, clinical examinations and urinary fluorine. Linear regression analysis was done. The values of fluorine in the air of workplaces ranged from 0.1 to 3.7 mg/m3 air during the study. Twenty five point and seven percent of exposed workers presented chronic rhinitis, laryngotracheitis and bronchitis. The smoking habit was similar in both groups. The incidence of chronic bronchitis was significantly higher in exposed workers compared to the non-exposed ones. The values of urinary fluorine were higher in the exposed versus the control group. Linear regression analysis has shown positive correlations between the fluorine exposure and incidence of chronic bronchitis (r=0.75), as well as the incidence of chronic respiratory diseases (r=0.71). Fluorine exposure may be responsible for the high incidence of chronic irritative respiratory diseases, especially for chronic bronchitis in exposed workers. For diseases prevention it is advisable to reduce the levels of fluorine in the air of workplaces and to decrease the concentration of fluorine compounds in the composition of enamel.

Mortality from non-malignant diseases among male Norwegian asphalt workers

BACKGROUND

The possible associations between asphalt work and mortality from non-malignant diseases in a cohort of male Norwegian asphalt workers that formed part of the European asphalt worker mortality study are examined.

METHODS

The mortality experience among 8,610 male workers ever employed in asphalt work was observed from 01.01.1970 until 12.31.1996, yielding 127,636 person years of observation. The cause-specific deaths observed in the study cohort were compared with the expected figures calculated from 5-year period- and age-specific national death rates. A study-specific job exposure matrix was used for individual-individual exposure estimates.

RESULTS

Eight hundred and three workers died during the observation period (SMR = 0.92, 95% confidence intervals (CI) = 0.58, 1.40). The mortality from non-malignant respiratory diseases was elevated (SMR = 1.25, 95%CI = 0.97, 1.58) and was associated with years since first employment in the asphalt industry. Mortality from respiratory diseases was highest among the workers first employed in the 1960s. Among the different job types held by the workers the pavers and mastic asphalt workers had the highest mortality from respiratory diseases. A weak dose-response was found with cumulative exposure to PAH and bitumen fume and mortality from non-malignant respiratory diseases in analyses employing the job-exposure matrix. Overall mortality, the mortality from circulatory diseases (SMR = 0.93, 95%CI = 0.83, 1.03) and external causes (SMR = 0.90, 95%CI = 0.72, 1.11) was lower than expected.

CONCLUSIONS

Mortality from respiratory diseases was found somewhat elevated among the asphalt workers. There was some evidence of exposure-response with both bitumen fume and PAH exposure. PAH from coal tar contributes to the PAH exposure.