More than fifty percent of the U.S. population tested positive to oneor more allergens, according to a large national study. The newfindings, based on data from the third National Health and NutritionExamination Survey (NHANES III), shows that 54.3% of individuals aged6-59 years old had a positive skin test response to at least one of the10 allergens tested. The highest prevalence rates were for dust mite,rye, ragweed, and cockroach, with about 25% of the population testingpositive to each allergen. Peanut allergy was the least common, with 9%of the population reacting positively to that food allergen.
The new findings published in the August issue of the Journal ofAllergy and Clinical Immunology were conducted by researchers at theNational Institute of Environmental Health Sciences (NIEHS) and theNational Institute of Allergy and Infectious Diseases, both componentsof the National Institutes of Health.
A positive skin test result may mean the individual is morevulnerable to asthma, hay fever, and eczema. "Asthma is one of theworld's most significant chronic health conditions," said David A.Schwartz, MD, the NIEHS Director. "Understanding what may account forthe rising worldwide asthma rates will allow us to develop moreeffective prevention and treatment approaches."
NHANES III is a nationally representative survey conducted bythe Centers for Disease Control and Prevention between 1988-1994 todetermine the health and nutritional status of the U.S. population.Approximately 10,500 individuals participated in the skin testing.During these tests, skin was exposed to allergy-causing substances(allergens) and a positive test was determined by the size of thereaction on the skin. The 10 allergens tested include: Dust mite,german cockroach, cat, perennial rye, short ragweed, Bermuda grass,Russian thistle, White oak, Alternia alternata, and peanuts.
Researchers also compared skin test responses between NHANESIII and the previous survey, NHANES II, conducted from 1976-1980. Theprevalence of a positive skin test response was much higher in NHANESIII than in NHANES II.
According to the lead author, Samuel J. Arbes, Ph.D. of NIEHS, "Anincrease in prevalence is consistent with reports from other countriesand coincides with an increase in asthma cases during that time." Inthe U.S., the prevalence of asthma increased 73.9% from 1980 to 1996.However, Dr. Arbes was quick to point out that differences in skin testprocedures between the two surveys prevent the authors fromdefinitively concluding that the prevalence of skin test positivity hasincreased in the U.S. population.
"There is still much we don't understand about why somepeople become sensitized to allergens and others do not," said DarrylC. Zeldin, MD, senior author on the paper. "Much more research isneeded in order for us to understand the complex relationships betweenexposures to allergens, the development of allergic sensitization, andthe onset and exacerbation of allergic diseases such as asthma."
The researchers recently added an allergy component to NHANES2005-2006. In addition to the other NHANES data collection components,dust samples from the homes of 10,000 individuals are being analyzedfor allergens, and blood samples taken from these individuals are beingexamined for antibodies to those allergens. This new NHANES 2005-2006allergy component will allow researchers to gain a greaterunderstanding of asthma and the roles that indoor allergens play inasthma and other allergic diseases.
NIEHS, a component of the National Institutes of Health, supportsresearch to understand the effects of the environment on human health.NIAID supports basic and applied research to prevent, diagnose andtreat infectious diseases such as HIV/AIDS and other sexuallytransmitted infections, influenza, tuberculosis, malaria and illnessfrom potential agents of bioterrorism. NIAID also supports research ontransplantation and immune-related illnesses, including autoimmunedisorders, asthma and allergies. For more information about allergensand other environmental health topics, please visit the NIEHS websiteat http://www.niehs.nih.gov/ or the NIAID website at http://www.niaid.nih.gov.
Materials provided by NIH/National Institute of Environmental Health Sciences. Note: Content may be edited for style and length.
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