Women who either were or had been domestic cleaners were more than twice as likely (12%) to develop asthma as women who had never worked as domestic cleaners (5%). In a study covering 4521 women, Dr. Josep Anto and colleagues at the Municipal Institute of Medical Research in Barcelona (Spain) also found that
women who had worked as cleaners in hospitals and health clinics also had an increased risk, but smaller. Hotel, laboratory and kitchen cleaners had a slight but insignificantly increased risk. There was no increased risk for office cleaners.

It was unclear why there would be a difference according to the type of place cleaned. Cleaners are exposed to a wide range of chemicals in cleaning products as well as house dust mites and other allergens.