Does Aluminum Smelting Cause Lung Disease?

Abstract

The evidence concerning a relationship between work in the aluminum industry and lung disease has been reviewed using epidemiologic criteria. Adequate data on environmental exposure are rarely presented. Case series on aluminum potroom workers over the past 50 years have identified an asthmalike syndrome that appears to be due to an irritant rather than an allergic mechanism. These studies have been supported by evidence of within shift variability of measures of lung function. However, to date, there is inadequate evidence to resolve the question of whether potroom exposure initiates asthma or merely precipitates asthmalike symptoms in a predisposed individual. Cross-sectional studies have demonstrated evidence of reduced lung function, consistent with chronic airflow limitation. In exposed aluminum smelter workers compared to unexposed control subjects. Cigarette smoking, the major potential confounding variable, has been measured and accounted for in multivariate analyses. To date, evidence is lacking from longitudinal studies about the development of disabling chronic obstructive lung disease. Exposure to coal tar pitch volatiles in the production and consumption of anodes has biologic plausibility for an association of lung cancer with work in an aluminum smelter. Although retrospective mortality studies have failed to account for the probable high prevalence of smoking in blue collar workers, the relative risk of lung cancer is very low if present at all. Pulmonary fibrosis has not been shown to be a significant problem in aluminum smelter workers. Future research in the aluminum industry needs to concentrate on longitudinal studies, preferably with an inception cohort for the investigation of potroom asthma.

Reduced bronchial CD4+ T-cell density in smokers with occupational asthma

“…The controls consisted of 15 healthy potroom workers (eight nonsmokers and seven smokers) and 10 healthy, nonexposed subjects (all nonsmokers). The diagnosis of occupational asthma was set by confirming the diagnosis of bronchial asthma according to international guidelines [9] and by establishing a causal link between asthma and the working environment, in line with previously defined criteria for occupational asthma in the aluminium industry [10]. Serial monitoring of peak expiratory flow was performed both at work and away from work.…”

Nonmalignant mortality among workers in six Norwegian aluminum plants

“…Several morbidity studies have found associations between potroom work and obstructive lung disease, while some cross-sectional morbidity studies have not been able to detect any work-related respiratory effect (18). However, workers leaving or changing jobs because of symptoms would lower the prevalence of health problems in the work force and tend to attenuate dose-response associations.…”

The etiology of occupational pulmonary aluminosis - the past and the present

“…21,22 ). A clear obstructive pattern of pulmonary ventilation parameters was repeatedly found in aluminium potroom workers 20,[23][24][25] . Radiographic findings may vary considerably, showing nodular or slightly irregular opacities that may merge into more prominent formations, most frequently in the upper lung fields 15,16,21,26 .…”

“…Crepitation is also reported 16 . Restrictive ventilatory defects are observed, sometimes accompanied by decreased diffusing capacity 12,15,18,20 . On the other hand, Townsend et al reported a relationship of impaired lung function to a higher prevalence of small opacities and a decrease in FEV 1 in workers with increasing duration and cumulative total dust exposure (in one study exposure of 20 or more years) (ref.…”