A study of more than 15,500 people from 26 areas in 12 industrialised countries, including the United Kingdom, New Zealand and Spain, found that the risk of asthma was highest among farmers, painters, plastics workers and cleaners. In the biggest population study conducted on occupational asthma, the researchers found that up to 10 per cent of cases in young adults were related to their work.
Asthma is a common disease, worldwide affecting one in twenty adults and one in four children. It inflames the airways, causing them to over- react to dust, cold air, smoke and infections. The lining of the airways also becomes swollen, which can make breathing difficult. The study, done at the respiratory and environmental health research unit, in Bar- celona, provides evidence of asthma being developed or aggravated because of someone's occupation.
Not only those in paid work are at risk; housewives have a higher incidence of asthma than office workers. "About 5 per cent of asthma among women may be due to dust and other airborne material in the home," said Dr Joseph Anto, of the research unit. "The prevalence of occupational asthma in women and in specific occupations has been underestimated and should be an important public health issue in industrialised countries."
The findings, published in The Lancet, showed that the levels of asthma for farmers and cleaners were consistent across all 12 countries. The highest rates for farmers were in Italy, Australia and New Zealand.
Excess risks of asthma of 30 to 50 per cent were found for people who worked with biological dusts, mineral dusts and fumes. Of the 15,637 people assessed in Australia, Belgium, Germany, Iceland, Ireland, Italy, New Zealand, Norway, Spain, Sweden, the UK and United States, cleaners, the biggest of the 16 occupational groups, showed an increased risk of more than 30 per cent.
Dr Anto said: "Cleaners are commonly exposed to substances known to cause asthma, such as chlorine and acids, detergents and dusts."
The researchers also found that the incidence of asthma attributable to occupational exposure among women, excluding housewives, was higher than expected. Many different groups of workers were at high risk of asthma, including textile workers and many farm workers were also female. "Under-reporting of occupational asthma may be more common among women particularly if the potential adverse effects of household exposures on health are included," Dr Anto said.
A separate study, of nearly 3,000 asthma sufferers in Europe, showed nearly one in six adults had taken time off work because of his or her asthma and a similar number said the illness had influenced their choice of job. The survey, done by Asthma Insights and Realities in Europe, showed that nearly a quarter of sufferers had been woken up at night by their symptoms at least once a week in the past month.