11/08/2009 - Press release
The study published in the Journal of Allergy and Clinical Immunology, analysed 3,626 people from 10 European countries who are responsible for cleaning at their homes
Researchers at the Centre for Research in Environmental Epidemiology (CREAL) and the Municipal Institute of Medical Research (IMIM-Hospital del Mar) have observed that the household use of bleach is associated with a lower sensitivity to allergens, both inside the home (for example, cat allergens) as well as those outside the home (pollen allergens). However, they also observed an elevated tendency for non-allergenic respiratory symptoms among those who used bleach four or more days a week.
Chlorine derivates like bleach have been used for more than 200 years to whiten, clean and disinfect. Today, bleach is the product that is most-often used in homes around the world as a disinfectant and laundry whitener. Nevertheless, a large difference ranging from 17% in Switzerland to 92% in Spain was noted in the use of bleach between the countries.
The purpose of this epidemiological study was to analyse the relationship between the household use of bleach and allergy sensitivity, allergic diseases and the respiratory health of adults. Prior studies had already shown that the professional use of bleach was linked to respiratory symptoms and it was known that bleach was capable of allergen inactivation, even reducing the risk of allergies in children.
The authors selected 3,626 people who were responsible for cleaning their homes to participate in the 2nd European Community Respiratory Health Survey, which was conducted in 10 countries. Data was available for a parameter used to measure the allergy sensitivity of these individuals (specific serum IgE) for four environmental allergens. The authors interviewed the participants in order to establish how often they used bleach as well as the nature of their respiratory symptoms. The levels of household dust mite allergens and cat allergens in mattress dust were also measured in the participants’ homes.
According to Jan-Paul Zock, the first author of the article, “bleach has a paradoxical effect as it seems that on the one hand, it reduces allergy sensitivity; but on the other hand, it increases non-allergenic respiratory symptoms". However, the authors warn that further studies are still needed in order to explain this relationship and to assess the implications of this for public health.
Domestic use of hypochlorite bleach, atopic sensitization, and respiratory symptoms in adults. Journal of Allergy & Clinical Immunology. DOI: 10.1016/j.jaci.2009.06.007