3.24 Lung disease, smoking and occupational exposures
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Workplace exposures to a range of substances can cause illness. For example, environments containing fine particulate matter from grains, flours, plants, coal dust, asbestos, silica, wood, feathers, insects and fungi, drugs and enzymes, chlorofluorocarbons, alcohols, metals and their salts and welding fumes can cause asthma, progressive lung damage and other serious respiratory disease.130, 131 Combining smoking with these exposures may greatly increase disease risk.131
A well-documented example is the interaction between workplace exposure to asbestos and cigarette smoking. Among the population not exposed to asbestos, smoking increases the lung cancer rate approximately 10-fold. In non-smoking asbestos workers, the lung cancer rate is increased five-fold; but among asbestos workers who smoke, the lung cancer rate is increased 50-fold. In other words, for those workers who both smoke and are exposed to asbestos, the risk of developing and dying from lung cancer is 50 times greater than the risk for individuals who neither smoke nor are exposed to asbestos at work. The risk is also dose-responsive, varying with exposure to both contributing factors. Heavy smokers heavily exposed to asbestos will have a higher than 50-fold increase.131 In Australia, most exposure to asbestos now occurs through the removal of asbestos from buildings, but the long lag-time for development of asbestos-caused disease means that death rates will continue to rise for the next two decades.132 There is also ample evidence suggesting that exposures to petrochemicals, aromatic amines, ionising radiation and pesticides interact with tobacco smoke.131
The US Surgeon General has concluded that 'for the majority of American workers who smoke, cigarette smoke represents a greater cause of death and disability than their workplace environment.'131 The Australian Burden of Disease Study confirms this. It is estimated that in 2003, occupational exposures and hazards accounted for 2% of the total disease and injury burden[5] and 1.3% of all deaths, while tobacco use accounted for 7.8% of the total disease and injury burden and 11.7% of all deaths.6
The accumulation of evidence about workplace health hazards over previous decades has lead to the introduction of industrial health and safety standards that have greatly reduced exposures to carcinogenic and other toxic substances in developed countries. However, the relocation of hazardous industry to less-developed countries, where occupational safety may be less regulated (and where, incidentally, there is more likely to be a higher prevalence of smoking) is a major cause for concern.132
[5] The measure used to express total burden of disease and injury is the 'disability-adjusted life year' (DALY). The DALY 'describes the amount of time lost due to both fatal and non-fatal events; that is, years of life lost due to premature death coupled with years of 'healthy' life lost due to disability.' 6 p2
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