Allergies - NIH Research Shows a Pets Help Children to Avoid Developing Allergies

The following is a reprint of an National Institute of Health news release that discusses recent findings that the presence of pets may help children to resist developing allergies. 
FOR IMMEDIATE RELEASE
Tuesday, August 27, 2002
4:00 p.m. ET
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Multiple Pets May Decrease Children's Allergy Risk
Children raised in a house with two or more dogs or cats during the first year of life may be less likely to develop allergic diseases as compared with children raised without pets, according to a study in the August 28 issue of the Journal of the American Medical Association. The study was supported by the National Institute of Allergy and Infectious Diseases (NIAID) and the National Institute of Environmental Health Sciences (NIEHS).

"The striking finding here is that high pet exposure early in life appears to protect against not only pet allergy but also other types of common allergies, such as allergy to dust mites, ragweed, and grass," says Marshall Plaut, M.D., chief of the allergic mechanisms section at NIAID. "Other studies have suggested a protective effect of pet exposure on allergy and asthma symptoms, but generally have looked only at whether pet exposure reduced pet allergy. This new finding changes the way scientists think about pet exposure; scientists must now figure out how pet exposure causes a general shift of the immune system away from an allergic response."

In their paper, lead author Dennis R. Ownby, M.D., of the Medical College of Georgia, and colleagues suggest that bacteria carried by pets may be responsible for suppressing the immune system's allergic response. These bacteria release molecules called endotoxins, and endotoxins are believed to shift the developing immune system away from responding to allergens through a class of lymphocytes called Th-2 cells, which are associated with allergic reactions. Instead, endotoxins may stimulate the immune system to activate Th-1 cells, which may block allergic reactions.

The researchers followed 474 children from birth to six or seven years of age. When the children were one year old, the researchers contacted parents by telephone to find out how many pets were in the home. When the children were two years old, researchers measured the level of dust mite allergen in their bedrooms. When the children were six or seven, the researchers tested them for allergic antibodies to common allergens by two approaches a skin prick test and a blood measurement.

After adjusting for factors such as dust mite allergen levels, parental smoking, and current dog or cat ownership, the researchers found that children exposed to two or more dogs or cats during the first year of life were on average 66 to 77 percent less likely to have any allergic antibodies to common allergens, as compared with children exposed to only one or no pets during their first year.

"Our findings suggest an area of research with many possibilities, one that could potentially bear fruit over the next decade or so," says Dr. Ownby. "If we could find out exactly what it is about pets or the bacteria they carry that prevents the allergic response, scientists might be able to develop a new allergy therapy based on that knowledge."

NIAID is a component of the National Institutes of Health (NIH). NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.

NIEHS is the component of NIH that conducts and supports research on the environmental causes and triggers of disease and our human susceptibility to them.

Press releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov.

The National Institute of Allergy and Infectious Diseases is a component of the National Institutes of Health, U.S. Department of Health and Human Services.


Reference: DR Ownby et al. Exposure to dogs and cats in the first year of life and risk of allergic sensitization at 6 to 7 years of age. Journal of the American Medical Association 288(8): 963-72 (2002).

What to do to prevent or remove pet and dust mite allergens?

  1. Remove carpeting and replace with wood, tile, linoleum, or vinyl floor covering. Remove cloth drapes and blinds. (If you have carpet, vacuum every day.) Vacuuming your carpets and upholstery every week can help. See the caution about vacuuming below under tips. Vacuums with high-efficiency filters pick up more dust mites, but even standard vacuums work well enough. 
  2. Reduce Temperature and humidity: Dust mites love warm, humid conditions, above 70 F (21 C) and 50% humidity Temperature: Keep the thermostat in the house below 70 degrees. Humidity: Effective control of mites would require the maintenance of relative humidity's below 50 percent. A study (Feb 2005) by Kingston University (London UK) shows that simply by leaving your bed unmade each morning, with the sheets to be exposed to the air, allows the sheets to dry out, and substantially reduces the numbers of dust mites. Some researchers feel it is important to focus on decreasing indoor humidity, especially during the winter period to reduce dust mite populations. One might forsake humidifier use during winter periods (or limit it to the bedroom only at night, then ventilate the room during the day). It will help to use dehumidifiers during high-humidity periods, or use central air conditioning. So if you use a humidifier in the winter, adjust it to produce 35% to 45% humidity. Some humidifiers have this control built in; with others, you'll need a humidity gauge (usually sold with a thermometer at Costco, Sam's Club, Wal-Mart, Target, etc.). And generally, homes that have their air conditioners on constantly in the summer and dry heat in the winter have lower mite counts than non-air conditioned homes.
  3. Protect Bedding - The most effective means is to enclose the mattress top and sides with a plastic cover or other dust mite impervious cover (available here, click on allergy bedding on the left in the new page), thoroughly vacuuming mattress pillows and the base of the bed. Put an airtight plastic or polyurethane cover over your mattress. This is the method recommended by Consumer Reports (see their article here). This tip is number one for a reason: it is in your bed (including the baby's crib) that you are closest to the mites and their feces and enclosing the mattress and pillows in a dust mite cover virtually eliminates the mites here.  There is a website, The Allergy Store, that we recommend that sells allergy controls, like the dustmite-proof fitted sheets. Mattresses covered with "fitted sheets" help prevent the accumulation of human skin scales on the surface.  These sheets have the advantage of being waterproof, too, which helps protect your mattress from spills, babies and toddler's waste, too.

 See this page for much more information about dust mites and how to control them.
 



Source page: http://www.nih.gov/news/pr/aug2002/niaid-27.htm


 



 

 

This page was updated on 30-Mar-2016