No justification for claims that cleaning and hygiene contribute to an increase in allergies

May 20 2004

A landmark report by the London-based International Scientific Forum on Home Hygiene (IFH) on the so-called hygiene hypothesis finds "no justification" for claims that cleaning and hygiene contribute to an increase in allergies. The Soap and Detergent Association (SDA) says the 224-page report "reiterates what we've known all along: good hygiene equals good health."

Established in 1926, SDA is dedicated to advancing public understanding of the safety and benefits of cleaning products. "In very simple terms, good hygiene saves lives," said Ernie Rosenberg, SDA President and CEO. "Cleanliness has a highly beneficial effect on our health by combating the spread of many kinds of contaminants, infectious agents and allergens." Some proponents of the hygiene hypothesis have claimed that cleaner homes lead to fewer childhood infections and an increased susceptibility to allergies and asthma.

The IFH report, available online at http://www.ifh-homehygiene.org/2003/2hypothesis/hh.htm, notes there is evidence that changing exposure to microbes may be a factor in the rise of allergies. But it finds "no evidence that cleaning habits prevalent today are to blame" and "firmly dispels the notion that we are living in super-clean, germ-free homes." "The thorough and exhaustive research done by IFH dispels the 'urban myth' status that the hygiene hypothesis has achieved," said SDA's Rosenberg. "There is sufficient data that tie insect and rodent infestation, mold and dust mites to serious asthma and allergy attacks. Suggesting that 'dirty is better than clean' is irresponsible." SDA and its member companies have worked with public health groups to showcase how cleaning is an inexpensive and beneficial way to reduce asthma and allergy triggers in the home. Free online materials for educators, public health professionals, policymakers, and families are available on SDA's website, at http://www.cleaning101.com/asthma.

The IFH is a non-profit, non-government organization comprising scientists and healthcare professionals who play an active role in hygiene policy and scientific research. "The Hygiene Hypothesis and Its Implications for Hygiene" was produced by Dr. Rosalind Stanwell-Smith, an Honorary Senior Lecturer at the London School of Hygiene and Tropical Medicine, and Professor Sally Bloomfield, Honorary Professor at the London School of Hygiene and Tropical Medicine's Hygiene Centre. Other key findings from the report:

• "While patterns of infection exposure and outcome have changed in developed countries over the last century, infection remains a major cause of mortality in world terms and, for two billion or more people, poor sanitation makes them vulnerable to a wide range of pathogens. Any suggestion that we should relax hygiene and sanitation in the developed world is irresponsible from the global perspective."
• "The definition of microbial exposure in the hygiene hypothesis is still poorly understood: the concept of allowing a bit of beneficial dirt back into the environment is sustainable only from an academic viewpoint. In practice, any attempt to provide 'controlled dirtiness' in the environment would inevitably raise the risk of invasive infection. 'Controlled dirtiness' is not a feasible concept, raising questions such as: how often should people wash their hands or clean chopping boards; or how long washing should be delayed after exposure to dirty environments?"
• "This review suggests that there is no justification for a relaxation in hygiene procedures aimed at preventing infection transmission in the home ... [N]evertheless, the findings of this report suggests a much-needed impetus to develop a more focused approach to hygiene practice in the home. We can be clean, hygienic and healthy without attempting to create a sterile environment in our homes or a sterile 'cocoon' around our infants."

Additional resources: London School of Hygiene & Tropical Medicine press release, http://www.lshtm.ac.uk/news/2004/risingallergies.html. International Scientific Forum on Home Hygiene, http://www.ifh-homehygiene.org SDA: Cleaning to Control Allergies and Asthma: http://www.cleaning101.com/health/NewAllergies The Soap and Detergent Association (http://www.cleaning101.com) is the non-profit trade association representing manufacturers of household, industrial, and institutional cleaning products; their ingredients; and finished packaging; and oleochemical producers. SDA members produce more than 90 percent of the cleaning products marketed in the U.S. The SDA is located at 1500 K Street, NW, Suite 300, Washington, DC 20005.