Day Care Settings Are A Significant Source Of Indoor Allergens

"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 1.

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/.