The use of spray cleaners as little as once a week increased the risk of developing asthma by nearly 50 percent, a new study found. (file photo: xinhua)

But whether or not the cleaning products are a direct cause of asthma, or simply a trigger for people who already have the disease, is not clear from this epidemiological study, which was published in the October issue of the American Journal of Respiratory and Critical Care Medicine.

Researchers, however, believe that spray cleaners can be a cause of new-onset asthma, because the people included in this study did not have asthma or asthma symptoms at the start of the study.

"Cleaning sprays, especially air fresheners, furniture cleaners and glass cleaners, had a particularly strong effect. The risk of developing asthma increased with the frequency of cleaning and number of different sprays used, but on average was 30 to 50 percent higher in people regularly exposed to cleaning sprays than in others," said the study's lead author, Jan-Paul Zock, a research fellow at the Center for Research in Environmental Epidemiology at the Municipal Institute of Medical Research in Barcelona, Spain.

The most important thing consumers need to know, cautioned Zock, is that "cleaning sprays -- for sale in all supermarkets -- are not harmless, and their use may involve serious health risks."

Previous research has found an association between asthma and being employed as a professional cleaner. Other studies have also noted a link between respiratory symptoms and certain cleaning products, but Zock and his colleagues wanted to learn if typical household exposures to cleaning products would have any effect on the development of asthma.

Drawing on a 10-country database, called the European Community Respiratory Health Survey, the researchers identified more than 3,500 people without any history of asthma or asthma symptoms. All reported being responsible for the cleaning of their homes.

(Agencies via Xinhua News Agency October 16, 2007)