Allergies Plague More Than Half the U.S. Population

RESEARCH TRIANGLE PARK, North Carolina, August 8, 2005 (ENS) - For Americans aged six to 59, the chances are greater than 50-50 that that they will be allergic to at least one of 10 common substances. According to a large national study released on Thursday, more than 50 percent of the U.S. population in that age range tested positive to one or more allergens.

Based on data from the third National Health and Nutrition Examination Survey, researchers found that 54.3 percent of individuals tested had a positive skin test response to at least one of the 10 allergens tested. A positive skin test result may mean the individual is more vulnerable to asthma, hay fever, and eczema.

The highest prevalence rates were for dust mite, rye, ragweed, and cockroach, with about 25 percent of the population testing positive to each allergen.

Peanut allergy was the least common, with nine percent of the population reacting positively to that food allergen.

The new findings published in the August issue of the "Journal of Allergy and Clinical Immunology" were conducted by researchers at the National Institute of Environmental Health Sciences (NIEHS) and the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, both components of the National Institutes of Health.

"Asthma is one of the world's most significant chronic health conditions," said David Schwartz, MD, the NIEHS director. "Understanding what may account for the rising worldwide asthma rates will allow us to develop more effective prevention and treatment approaches."

The third National Health and Nutrition Examination Survey is a nationally representative survey conducted by the Centers for Disease Control and Prevention between 1988-1994 to determine the health and nutritional status of the U.S. population.

Common ragweed, Ambrosia artemisiifolia, is a plant typically found in disturbed areas. It is a species native to the United States, although many allergy sufferers wish it were not. (Photo by Mike Terry courtesy USFWS)

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 the third National Health and Nutrition Examination Survey (NHANES III) and the previous survey, known as NHANES II, conducted from 1976-1980.

Many more positive skin test responses were found in NHANES III than in NHANES II.

Says lead author Samuel Arbes, Ph.D. of NIEHS, "An increase in prevalence is consistent with reports from other countries and coincides with an increase in asthma cases during that time."

In the U.S., the prevalence of asthma increased 73.9 percent from 1980 to 1996. But Dr. Arbes was pointed out that differences in skin test procedures between the two surveys prevent the authors from definitively concluding that the prevalence of skin test positivity has increased in the U.S. population.

"There is still much we don't understand about why some people become sensitized to allergens and others do not," said Darryl Zeldin, MD, senior author on the paper. "Much more research is needed in order for us to understand the complex relationships between exposures to allergens, the development of allergic sensitization, and the onset and exacerbation of allergic diseases such as asthma."

While the results reported Thursday are from tests conducted from 1988-1994, the researchers want to obtain current skin test results. They have recently added an allergy component to NHANES 2005-2006.

Dust samples from the homes of 10,000 individuals are being analyzed for allergens, and blood samples taken from these individuals are being examined for antibodies to those allergens.

This new NHANES 2005-2006 allergy component will allow researchers to gain a greater understanding of asthma and the roles that indoor allergens play in asthma and other allergic diseases.

“Allergy and asthma control begins at home for more than 50 million Americans who have allergies, and the 20 million who have asthma,” said Mike Tringale, director of communications for the Asthma and Allergy Foundation of America, a citizens support group. “When allergy sufferers clean properly, they can manage their indoor air quality, and lessen the nasal congestion, coughing, sneezing, headaches and severe, flu-like symptoms, they often experience.”

For tips on cleaning to manage allergies, visit http://www.aafa.org/display.cfm?id=4

Results of a different study released in June showed that day care facilities in the South are "a significant source for indoor allergen levels."

The new study of 89 day care settings in two central North Carolina counties found detectable levels of seven common allergens from fungus, cats, cockroaches, dogs, dust mites, and mice in each facility tested. Both licensed family day care homes and child care centers are represented in the study. The levels were similar to those found in Southern homes.

Dust mites are insects in the arachnid family which includes spiders, scorpions and ticks. (Photo courtesy Asthma and Allergy Foundation of America)

According to the U.S. Census Bureau, 63 percent of children under five spend 37 hours a 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.

The Asthma and Allergy Foundation of America supports Senators Hillary Rodham Clinton, a New York Democrat, and Mike DeWine, an Ohio Republican, who introduced the Family Asthma Act of 2005 in the Senate on July 26. The bill is intended to address the unmet need for better asthma control and management, particularly in underserved populations.

"The government has done an incredible job recognizing the impact of asthma and working with the broad medical community to help millions of people better understand how to control this disease," said Chris Ward, a patient with asthma and allergies and president of the Asthma and Allergy Foundation of America.

"Yet, despite the availability of effective treatments and management strategies, a roadmap for asthma research and coordination of activity is needed to reach American communities most in need. The Family Asthma Act is that roadmap."

The Family Asthma Act authorizes $18 million in each of fiscal years 2006-2010 for pilot prevention and intervention research projects administered by the U.S. National Institutes of Health, an expansion of activities by the U.S. Centers for Disease Control and Prevention, better mechanisms to coordinate federal activities related to asthma, and new training grants for asthma care providers and education specialists.

Nearly 20 million Americans, including over six million children are diagnosed with asthma, and African Americans and certain Hispanic populations are most affected. Asthma prevalence is projected to reach a rate of one in 14 Americans and will affect one in five families by the year 2020, Ward says.

The National Heart Lung Blood Institute at the NIH estimates the annual cost of asthma in the U.S. in 2004 was over $16 billion.