Occupational lung disease

Asthma is the most common work-related lung disease. It is estimated that one in seven severe asthma exacerbations are linked to work-related exposures, and work-related exposures are thought to account for about 15% of all adulthood asthma.

There are a growing number of materials that have been linked with asthma:

• Proteins from animals, plants and seafood
• Man-made proteins used in fabrics, detergents and glue
• Metallic agents used in industrial factories
• Synthetic chemicals used in spray paints, foams and adhesives
• Existing asthma symptoms can also be worsened by the work environment and this is termed ‘work-aggravated asthma’.

Given the important role occupational factors can play in the development and worsening of asthma, the workplace is an important area to focus on for asthma prevention.

This occurs from a single incident resulting in a sudden and large exposure to a material, such as a chemical spillage, fire, gas explosions or exposure to large amounts of dust. Complications with lung health are also a major cause of death in people who are admitted for burn injuries. These exposures can lead to asthma and other rare conditions, such as metal fume fever and organic dust syndrome.

Groups commonly at risk include agricultural workers, fire fighters and emergency personnel. Research from Sweden and Finland found that one in 10 farmers has experienced an acute inhalation injury resulting from exposure to dust.

These infections occur from exposure to bacteria. They include:

• Tuberculosis (TB): Healthcare workers who are treating the condition in other people are the most at-risk group
• Legionnaires disease: This commonly spreads through air conditioning systems and usually affects hotels and leisure centre workers, people working on cruise ships and other crowded and confined areas such as schools
• Q Fever: This is caused by bacteria infecting farm animals, rodents or cats and dogs, putting agricultural workers at risk

Most COPD is caused by smoking, however research suggests that between 15% and 20% of COPD cases are at least partially triggered by a certain material or agent in the work environment.

This can be due to exposure to mineral dusts, irritant gases or vapours in the air. A build-up of these materials can lead to chronic cough, chronic bronchitis and COPD. Underground miners and agricultural workers are most at risk of developing the condition.

In Europe, over 39,000 deaths have been estimated for the year 2000 as a result of work-related exposures to dusts and fumes.

There are a number of rare interstitial lung diseases that are clearly linked with occupational exposures. These include:

Pneumoconiosis: This is caused by exposure to silica, asbestos or coal dust. Dust controls in workplaces and the illegalisation of asbestos in building work has meant there has been a decline in these conditions and they are usually found in people who suffered exposure to these substances many years ago. A total of 7,200 cases of pneumoconiosis related to exposures to asbestos, silica and coal dust has been estimated for the year 2000 in Europe.

Metal-related lung conditions: Lung disease can be caused by exposure to metals such as beryllium used in modern technology (e.g. aerospace engineering) or cobalt used in alloys and batteries. These conditions can often be confused with other diseases, such as sarcoidosis, and more work is needed to ensure they are recognised as occupational diseases.

Extrinsic allergic alveolitis: This is caused by an allergic reaction to an agent in the work environment that affects the alveoli (the small air sacs in the lungs). The causes are diverse and could be from organic dusts, wood processing, birds and bird feed or vegetable stores. Annual incidences have been estimated at 2-6 cases per 1,000 farmers in Sweden in 1980s.

Other interstitial lung diseases: Rare diseases can occur as a random outbreak linked to a work exposure. One example of this is an outbreak of a severe form of pneumonia in textile workers called Ardystil syndrome, caused by aerosolised paints. These rare outbreaks are a reminder that workers should not be exposed to aerosolised compounds unless they have been tested and are known to be safe.

Another area of concern is the use of nano-materials for various new applications. Although no robust research has yet confirmed that lung conditions are caused by exposure to nano-materials, some studies in animals have raised concerns about the damaging effects they may have on humans.

There are a number of cancer-causing work place exposures, including asbestos fibres, nickel compounds, arsenic, diesel exhausts and radon gas. These agents can also react with cigarette smoke to cause harmful effects. Passive smoke from colleagues is also categorised as a workplace exposure. 15% of lung cancer cases in men and 5% in women are thought to be caused by occupational exposures. Occupational lung cancer is often underreported as many people with lung cancer are current or former smokers.

Pleural disease is almost exclusively linked to exposure to asbestos. Although asbestos-use is now illegal, people who were exposed to the condition at a young age are now living with the illness in old age.

Pleural diseases can be non-malignant, which means the tumour does not have the potential to spread. These occur more frequently in people with only light exposure to asbestos.

Malignant forms of the disease include mesothelioma, which usually occurs 30 or more years after asbestos exposure and is predicted to kill 250,000 people between 1995 and 2029. According to this prediction, one in 150 men born between 1945 and 2050 will die of this tumour, for which there is no effective cure.