such as "Introduction", "Conclusion"..etc
Infants who experience viral respiratory
illnesses with wheezing are known to be at increased risk for developing asthma
later during childhood. It is not known, however, whether every type of
respiratory virus that produces wheezing presents similar risk. Using new
molecular techniques to identify different viruses, researchers now believe they
have pinpointed the biggest culprit: rhinovirus (RV).
found that rhinovirus, the most common cause of colds, contributes a
disproportionate amount towards future asthma development in comparison to other
viruses that also cause childhood wheezing," said principle investigator, Robert
F. Lemanske, Jr., M.D., head of the Division of Pediatric Allergy, Immunology,
and Rheumatology and Professor of Pediatrics and Medicine at the University of
Wisconsin School of Medicine and Public Health.
results were reported in the first issue for October of the American Journal of Respiratory and Critical
Care Medicine, published by the American Thoracic Society.
November 1998 to May 2000, researchers at the University of Wisconsin recruited nearly 300 newborns at
high risk for asthma (with one or both parents having had allergies or asthma)
to take part in their prospective cohort study on the etiology of asthma, the
Childhood Origins of Asthma (COAST) study. The children
were followed from birth to six years and evaluated for the presence of specific
viruses during wheezing illnesses.
years, 28 percent of the kids had asthma— and those who had wheezed with
rhinovirus were disproportionately among them. Children who wheezed with RV
during the first year of life were nearly three times as likely to have asthma
at age six, whereas children who wheezed with respiratory syncytial virus (RSV),
another common respiratory ailment that has been linked to asthma risk in
children, did not have an increased asthma risk.
older the children were, the greater the effect. Children who had wheezed with
RV in their second year of life were more than six times as likely to have
asthma. Wheezing with RV at three increased asthma odds by more than 30-fold.
study confirmed previous findings that wheezing with RSV any time during the
first three years led to a nearly three-fold increased asthma risk. However, the
novel finding is that "wheezing RV illnesses occurring at any time during the
first three years of life were associated with a nearly 10-fold increase in
asthma risk at six years, making them the most significant predictor of asthma
development in the high risk COAST cohort," wrote Daniel J. Jackson, M.D.,
Allergy and Immunology Fellow at the University of Wisconsin, lead author of the
nearly 90% of the children wheezing with RV during year three subsequently
developed asthma at age six," he wrote.
Whether RV causes asthma to develop, or
simply reveals children who are already predisposed to the disease (host-related
factors) remains an open question. Alternatively, "In genetically susceptible
children, RV wheezing illnesses could cause airway damage as well as subsequent
asthma (virus-related factors)," stated Dr. Jackson, pointing out that the
possibilities are not mutually exclusive and that additional research would be
required to resolve the question.
These findings mark a shift in medical
knowledge on the topic of virus-induced wheezing and subsequent asthma
development. John E. Heffner, M.D., past president of the ATS, stated
that "the results of this study represent important advances in our
understanding of childhood asthma because the investigators studied infants in
an outpatient setting. Prior studies examined more seriously ill, hospitalized
infants— mild viral illnesses may be just as important for later asthma as more
severe infections. Also, the elegant technique used to identify specific viruses
provides a foothold for understanding the unique viral attributes that cause
wheezing and— potentially— lead to asthma."
News release from American Thoracic Society on October 1, 2008.
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