Household cleaning products have been linked with asthma by research conducted in 10 countries.
The study was based on tests conducted on 3,503 people doing the cleaning in homes were free of asthma at baseline.
Frequency of use of 15 types of cleaning products was obtained in face-to-face interviews after nine years and incidence of asthma was measured.
Those who used cleaning sprays weekly were 49% more likely to develop asthma symptoms and 39% more likely to wheeze.
People using cleaning sprays more than four times a week were more than four times more likely to develop asthma.
American Journal of Respiratory and Critical Care Medicine (2007) 176: 735-741