More than fifty percent of the U.S. population tested
positive to one or more allergens, according to a large
national study. The new findings, based on data from
the third National Health and Nutrition Examination
Survey (NHANES III), shows that 54.3% of individuals
aged 6-59 years old had a positive skin test response
to at least one of the 10 allergens tested. The highest
prevalence rates were for dust mite, rye, ragweed, and
cockroach, with about 25% of the population testing
positive 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 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, both components of
the National Institutes of Health.
A positive skin test result may mean the individual
is more vulnerable to asthma, hay fever, and eczema. “Asthma
is one of the world’s most significant chronic health
conditions,” said David A. 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.”
NHANES III 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. 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 the
reaction 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
NHANES III and the previous survey, NHANES II, conducted
from 1976-1980. The prevalence of a positive skin test
response was much higher in NHANES III than in NHANES
II.
According to the lead author, Samuel J. 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% from 1980 to 1996.
However, Dr. Arbes was quick to point 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 C. 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.”
The researchers recently added an allergy component
to NHANES 2005-2006. In addition to the other NHANES
data collection components, 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.
NIEHS, a component of the National Institutes of Health,
supports research to understand the effects of the environment
on human health. NIAID supports basic and applied research
to prevent, diagnose and treat infectious diseases such
as HIV/AIDS and other sexually transmitted infections,
influenza, tuberculosis, malaria and illness from potential
agents of bioterrorism. NIAID also supports research
on transplantation and immune-related illnesses, including
autoimmune disorders, asthma and allergies. For more
information about allergens and other environmental
health topics, please visit the NIEHS website at http://www.niehs.nih.gov/ or the NIAID website at http://www.niaid.nih.gov.
The National Institutes of Health (NIH) — The
Nation's Medical Research Agency — is comprised
of 27 Institutes and Centers and is a component of
the U. S. Department of Health and Human Services.
It is the primary Federal agency for conducting and
supporting basic, clinical, and translational medical
research, and investigates the causes, treatments,
and cures for both common and rare diseases. For more
information about NIH and its programs, visit www.nih.gov.