September/October - West Virginia State Medical Association

Scientific Article |
Exercise Intolerance in Obese Children — is it Asthma?
Robert A. Kaslovsky, MD
Pediatric Pulmonary Division Chief,
Baystate Children’s Hospital,
Springfield, MA
Stephen B. Sondike, MD
Section Head, Adolescent Medicine,
WVU Physicians of Charleston and
Associate Professor of Pediatrics at
WVU Charleston Division
Stephanie Cummings, CMA
Abstract
This is a pilot study designed to
examine the frequency of asthma in
obese children who have exertional
dyspnea. Obese children who complained
of breathlessness with exercise and who
denied asthma were invited to enroll. If
there was evidence of airflow limitation on
spirometry, nebulized albuterol was
administered and spirometry was
repeated. If there was no significant
improvement or if the baseline spirometry
was normal, exercise testing was
performed. A total of 20 patients (ages
from 8 to 16 years) with BMI from 22 to 61
were enrolled. Of the 19 who completed
the study, 9 (47.3%) met criteria for
asthma. Recognizing and treating asthma
may lead to improved exercise tolerance
and improved weight status in these
obese individuals.
Introduction
Asthma is the most common
chronic disease of childhood. It is
estimated that 11.2% of the U.S.
population has at some time been
diagnosed with asthma, 1 and that
about 5 million children across
the U.S. are affected. 1 Asthma
is the leading cause of school
absenteeism due to chronic illness. 2
Untreated asthma may result in
serious consequences, including
lost school or work days, costly
hospitalizations, and possibly death.
Obesity (defined as body mass
index > 95th percentile for age) is
increasing in prevalence in children.
Data from NHANES I (1971–1974)
to NHANES 2003–2004 show
increases in overweight among
all age groups: Among preschoolaged
children, aged 2–5 years, the
prevalence of overweight increased
from 5.0% to 13.9%; among schoolaged
children, aged 6–11 years, the
prevalence of overweight increased
from 4.0% to 18.8%; and among
school-aged adolescents, aged 12–19
years, the prevalence of overweight
increased from 6.1% to 17.4%. 3
Given the increasing prevalence
of both asthma and obesity in
childhood, it is possible that a link
exists between these two conditions.
The medical literature has few
studies that address this question.
Gold et al examined the incidence
of asthma in a longitudinal study
of 9,828 children age 6 – 14 years in
six US cities over a five year period. 4
Girls who were heavier at baseline
were more likely to have asthma and
the risk of developing asthma over
the observation period increased with
increasing BMI. Similarly, Castro-
Rodriguez, et al found that girls
who became overweight or obese
between ages 6 and 11 were seven
times more likely to develop new
asthma between ages of 11 and 13
years. 5 A relationship between BMI
at age 6 and wheezing prevalence
at any age was not found. In an
analysis of outcomes of childhood
asthma in adolescent years, Guerra,
et al found that the mean BMI
was higher in a group with poorly
controlled asthma 6 suggesting that
obesity adversely affects asthma
control. Other studies have suggested
that weight reduction improves
symptoms and lung function in
obese adults with asthma. 6.7 Obese
individuals often have exercise
intolerance which is attributed to
deconditioning. The present study
sought to provide information on the
prevalence of undiagnosed asthma
in obese children who complain of
shortness of breath with exercise.
Methodology
Children age 6 to 18 years were
eligible for the study if they had BMI
> 95th percentile for age, and exercise
induced shortness of breath (see
figure 1). The questions outlined in
figure 2 were asked, and to qualify
for the study, the first two questions
had to be answered affirmatively,
and the last three had to be answered
“no”. Standard spirometry was
performed at rest, with measurement
of forced vital capacity (FVC), and
forced exhaled volume in one second
(FEV1). The reference values of
Polgar 9 for pediatric patients were
used, with normal values for these
parameters and for the ratio of
FEV1/FVC being greater than 80%.
If the test was deemed abnormal, an
inhaled bronchodilator (albuterol)
was administered via jet nebulizer,
and the test was test repeated after 10
to 15 minutes. An increase in 12% in
FEV1 indicated a positive response
to bronchodilator. If there was no
response to bronchodilator, or if the
test was deemed normal, patients
were scheduled for an exercise
challenge test, using a standard
treadmill exercise protocol. 10 After
completing the exercise protocol,
spirometry was performed at 5, 10,
15, and 20 minutes, and a positive
response was a drop in FEV1 >
12% from baseline for the diagnosis
of exercise induced asthma to
be made. If there was no drop in
FEV1, the test was deemed normal,
and the results were interpreted
as unlikely to be asthma
The proportion of tested children
with asthma was calculated by
dividing the number with either
an abnormal spirometry with
bronchodilator response, or a
12 West Virginia Medical Journal