Researchers studying day care facilities in the South have found the facilities to be a significant source for indoor allergen levels. A new study of 89 day care settings in two central North Carolina counties found detectable levels of seven common allergens from fungus, cats, cockroaches, dogs, dust mites, and mice in each facility tested. The levels were similar to those found in Southern homes.

“Because children spend a significant portion of time in day care settings, it is important that parents understand the risks of allergen exposure and know where these allergens can be found,” said David A. Schwartz, M.D., the new Director of the National Institute of Environmental Health Sciences (NIEHS), the part of the National Institutes of Health that supported the study. The study will be available online in the Journal of Allergy and Clinical Immunology on June 1st.

According to the U.S. Census Bureau, 63 percent of children under five spend 37 hours per week in child care. Exposure to indoor allergens has been shown in previous studies to increase the likelihood of developing asthma or allergic diseases, especially in vulnerable children.

Both licensed family day care homes and child care centers are represented in the study. The researchers used a three-pronged data collection approach to evaluate allergens in each care facility, including administering a questionnaire to each manager, observing the room where the children spent most of their time, and collecting dust samples from that room.

Dust was collected from up to four, one square meter areas of floor on both carpet and hard surfaces. Twenty facilities had dust collected from both surfaces.

Detectable levels of each allergen were found in every facility where dust samples were collected. Concentrations were the highest for allergens from cats, dogs, and a fungus known as Alternaria.

“Interestingly, similar to other studies, dog and cat allergens were detected in nearly all the facilities tested, although no dog or cat was observed in most,” said, Samuel Arbes, Ph.D., a NIEHS researcher and lead author on the study. “It is likely the pet allergens are brought in on the children’s clothing.”

The study also found significant differences between carpeted and non-carpeted surfaces. Concentrations for five of the allergens were lower on the non-carpeted surfaces.

The researchers compared the day care allergen levels to concentrations found in Southern homes collected previously as part of the National Survey of Lead and Allergens in Housing (NSLAH). The NSLAH collected samples from 831 homes representing various regions and settings across the country. Five of the seven allergen levels were statistically similar with only one of two dust mite allergens and mouse allergen being slightly higher in the NSLAH.

“The similarities in allergen levels between the day care centers and Southern home living rooms means children and the day care workers may be getting prolonged exposure to allergens,” said Dr. Arbes. “More research needs to be conducted to determine the effects of allergen exposures outside of the home.”

NIEHS, a component of the National Institutes of Health, supports research to understand the effects of the environment on human health. For more information about indoor allergens and other environmental health topics, please visit our website at http://www.niehs.nih.gov/.

Positive test responses were also more likely to be seen among men of all ages, people in their 20s of both sexes, minorities and those living in older homes.

For the next national health survey, under way this year and in 2006, skin tests are again being done for about 10,000 individuals nationwide, but researchers are also analyzing dust samples from the participants' homes. Blood samples from each person will also be analyzed to see if he or she has antibodies that indicate an allergy to the most common allergens in their homes.

"Understanding what may account for the rising worldwide asthma rates will allow us to develop more effective treatment and prevention approaches," said Dr. David Schwartz, director of the NIEHS.