In a new study, researchers looked at the potential impact of exposure to bleach in the home among more than 9000 children aged between 6 and 12, attending schools in The Netherlands, Finland and Spain. Parents completed a questionnaire on the frequency of flu; tonsillitis; sinusitis; bronchitis; otitis; and pneumonia infections their children had had in the last 12 months, and whether they used bleach to clean their homes at least once a week.
Bleach use was common in Spain (72% of respondents) and rare (7%) in Finland. After taking account of factors, such as passive smoking at home, parental education, presence of household mould, and use of bleach to clean school premises, the findings indicated that the frequency of infections were higher among children whose parents regularly used bleach to clean the home in all three countries. The differences were statistically significant for flu, tonsillitis, and any infection. The authors suggest that irritancy of volatile or airborne compounds generated during cleaning may damage the lining of lung cells, making it easier for infections to take hold. Bleach may also potentially suppress the immune system.
This study tends to ask more questions than it answers and is clearly intended to make the case for further research rather than show there is a real effect. By the authors’ admission, the reported health effects are rather modest, and were self-reported rather than medically diagnosed.
Since this is an observational study, no conclusions can be drawn about cause and effect. The authors noted potentially important confounding factors which they were not able to control for which could explain the results. For example, they didn’t have any information on the use of other cleaning products used in the home, and only basic information on the use of bleach in the home, making it difficult to differentiate between exposure levels. i.e. what concentrations were used, where the product was used, how much was used and how often, all of which would affect the extent of exposure and any response.
Importantly, the authors provide limited biological evidence to support the proposed mechanism by which bleach exposure might damage the respiratory epithelium and thereby lower resistance to infection.
We should be very careful in reporting these results. Oxidizing microbiocides such as chlorine bleach are used at concentrations ranging from 0.5 up to 50,000 ppm, and are a vital part of our armory to prevent infections in healthcare settings, water treatment, the food and pharmaceuticals industries – and also in the home when used in a targeted manner to prevent the spread of infectious germs. The vital importance of bleach to protect against infection was demonstrated in the recent and ongoing fight against Ebola in West Africa.”
The study can be found at: http://oem.bmj.com/content/early/2015/02/20/oemed-2014-102701
