No shocker here: > 90% of American homes have ≥ 3 detectable allergens, and 73% have at least 1 allergen at elevated levels, acceding to the largest U.S. indoor allergen study to date.
Using data from National Institute of Environmental Health Sciences (NHANES) 2005-2006, researchers studied levels of 8 common allergens (cat, dog, cockroach, mouse, rat, mold, and 2 types of dust mite allergens) in nearly 7,000 homes.
Mobile homes, older homes, rental homes, and rural homes were more likely to have higher amounts of indoor allergens, as were homes with pets and pests.
Elevated levels of dust mites were more common in the South and Northeast and humid regions. Cat and dust mite allergens were more common in rural settings compared with urban.
The NHANES 2005-2006 data allowed national comparisons for the first time of exposure and sensitization. Men and non-Hispanic blacks were less likely to be exposed to multiple allergens, and sensitization was more common in those groups compared with women and other racial groups, respectively. Exposure to several elevated allergens was most prevalent in rural areas. Sensitization rates were higher in urban areas.
The researchers emphasize that the relationships between allergen exposures, allergic sensitization, and disease are complex. They also note that studies are still investigating how allergen exposures interact with other environmental and genetic factors in asthma and allergies. However, among the tips they offer: vacuum every week, wash sheets and blankets in hot water every week, and lower indoor humidity levels below 50%.