Look At Relationship Between Asthma and Obesity
may increase the risk of asthma, suggest two new studies that
were presented at the American Lung Association/American Thoracic
Conference in Chicago April 24-29, 1998. In one
study, researchers using data from a study of more than 100,000
nurses found that the more overweight a nurse was, the greater
her risk of developing asthma in adulthood. The second study
found that the most overweight 26-year-olds were more likely
to have asthma than the thinnest ones.
Obesity and Asthma
Obesity and asthma are both on the rise in
developed nations. An estimated 14.6 million Americans, including
suffer from asthma. Between 1982 and 1994, the rate of asthma
rose 61%, while the rate of pediatric asthma rose 72%. According
to the National Institutes of Health, one in three Americans
is obese. Obesity is second only to smoking as a risk factor
for disease, accountable for about 300,000 deaths per year.
Both of the
studies set out to examine a possible relationship between
obesity and asthma. Until now, it was commonly assumed
that people with asthma may become overweight because their breathing
problems limit their activity, according to Carlos A. Camargo,
Jr., M.D., Dr.P.H., of the Harvard Medical School in Boston,
who led the nurses study on asthma.
"But with proper treatment, people with asthma should not
have activity limitations," he said.
In the nurses study, Dr. Camargo and colleagues used data from
the women in the Nurses Health Study II, a prospective study
of 116,678 female nurses. Of those nurses, they tracked the 89,061
who did not have asthma in 1991, and found that 1,652 developed
asthma between 1991 and 1995. Those who were most obese in 1991
were three times as likely to develop asthma as those who were
the least overweight.
In the second study, British researchers studied the relationship
of birthweight, weight and height at age 26 to the prevalence
of asthma in more than 8,000 people. The heaviest adults were
80% more likely to have asthma than the thinnest ones, according
to researcher Seif O. Shaheen, Ph.D., of the United Medical and
Dental Schools in London.
little research had yet been done to examine how obesity might
to asthma, however, Dr. Camargo said it is possible
that being overweight somehow compresses the airways, making
them smaller and therefore more reactive to cold or other asthma
Dr. Shaheen offered several other possible explanations. One
is that obese people tend to exercise less, and exercise may
be directly beneficial to the lungs and prevent asthma. Another
theory is that obese people may be more at risk because they
eat a different type of diet.
in both studies measured subjects' obesity in terms of body
index (BMI), a measure of how overweight someone
is after taking into account their height. The higher the BMI
the fatter the person; there are conventional cut-offs for "normal
weight" (BMI 20-25), "overweight" (BMI 25-30)
and "obese" (BMI>30).
American Thoracic Society (ATS)
to the Allergy, Sinusitis, and Asthma Ezine
to Asthma Reference Section
to Health Main Reference Category
Return to NEWSdial.com