A recent study from the National Institutes of Health (NIH) shows over 90 percent of U.S. homes have three or more detectable allergens and 73 percent have at least one allergen at an elevated level.
The study, published in the Journal of Allergy and Clinical Immunology, is one of the largest indoor allergen studies done to date, according to the NIH.
"Elevated allergen levels can exacerbate symptoms in people who suffer from asthma and allergies, so it is crucial to understand the factors that contribute," Dr. Darryl Zeldin, senior author and scientific director at the National Institute of Environmental Health Sciences (NIEHS), said in a press release.
Researchers used 2005-06 data from the National Health and Nutrition Examination Survey to study eight common allergens in bedrooms which include dog, cat, cockroach, rat, mouse, mold and two different dust mite allergens in 7,000 U.S. homes.
Pets and pests were the major culprit of indoor allergens, according to the study, with more allergens in older homes, mobile homes, homes in rural areas and rental homes. The study also found exposure levels for individual allergens varied with age, sex, race, ethnicity and socioeconomic status, according to the release.
The NIH recommends weekly vacuuming of carpets and washing of sheets and blankets in hot water and limiting pets' access to bedrooms, keeping humidity levels below 50 percent and sealing entry points as ways to reduce allergen exposure.