Professor Peter Openshaw, President of the British Society for Immunology and Professor of Experimental Medicine at Imperial College London, said:
“Although the authors acknowledge that cross-sectional studies raise questions rather than show causality, they conclude that domestic exposure to bleach may increase the risk of respiratory infections. The effect is not large (about a 20% increase), and it is possible that other benefits of domestic hygiene (that are not assessed) may outweigh the adverse effects on respiratory infection that they report. It’s important to recognise that the study relies on self-reported use of bleach and illness rather than objective measurements of exposure and health outcomes. Households that report the use of bleach may well have different thresholds for reporting illness compared to those that don’t.
“What is needed now is a study that comprehensively measures indoor air pollution (including chlorine and other volatiles from cleaning products), uses validated objective measures of respiratory infection and investigates the possible immunological mechanisms by which use of cleaning products might influence the frequency of respiratory infection. The study is interesting, but given these limitations the findings should be treated with caution. I will continue to (sometimes) use bleach at home.”