Now that Missourians have closed their windows and cranked up the heat for the cold winter ahead, a new indoor allergen study conducted by researchers from the National Institutes of Health [NIH] may be of note. Considered the nation’s largest study of its kind to date, the NIH research measured allergen levels present in the bedrooms of nearly 7,000 homes across the U.S. It found that more than 90 percent of those homes had three or more detectable allergens, and 73 percent had at least one allergen at elevated levels. The findings recently were published in the Journal of Allergy and Clinical Immunology.
Using data from the National Health and Nutrition Examination Survey, the researchers studied levels of eight common allergens: cat, dog, cockroach, mouse, rat, mold and two types of dust mite allergens. Nationwide, cat, dog and mouse were the most commonly detected allergens, followed by dust mites. In the Midwest, the allergens most commonly found at high levels were dog, cat, dust mites and, to a lesser degree, mold. Overall, the study found that the presence of pets in the home, along with insects and other pests, had a major influence on high levels of indoor allergens.
They also found that levels of different allergens vary between geographic locations, overall climate conditions and type of housing – for example, multiple allergens were more likely in the bedrooms of mobile homes, older homes, rental homes and homes in rural areas.
“Elevated allergen levels can exacerbate symptoms in people who suffer from asthma and allergies, so it is crucial to understand the factors that contribute,” said Darryl Zeldin, M.D., the study’s senior author and scientific director at the National Institute of Environmental Health Sciences, which is part of NIH.
The NIH also outlined the following preventive steps homeowners can take to help reduce exposure to indoor allergens:
• Vacuum carpets and upholstered furniture at least once per week.
• Wash sheets and blankets in hot water every week.
• Encase mattresses, pillows and box springs in allergen-impermeable covers.
• Lower humidity levels in the home below 50 percent.
• For those with sensitivity to pet allergens, remove pets from the home, or at least limit their access to bedrooms.
• Seal entry points and eliminate nesting places for pests, and remove their food and water sources.