INTRODUCTION
Obesity and asthma commonly co-exist in children and obesity is related
to more severe asthma as well as deteriorated spirometric indices such
as FEV11, 2. Cottrell et al have reported that asthma
prevalence shows a parallel increase with body mass index (BMI)
indices3. Moreover, a prospective study in school age
children demonstrated that asthma prevalence increases with
obesity4. There are many theories that explain this
co-existence; mechanical influences of obesity on the airway as depicted
by the decreased FEV1 as mentioned above, chronic inflammation due to
increased leptin and oxidative stress in obesity, hormonal changes such
as decreased progesterone leading to blunted beta-2 receptor response in
obese individuals and co-morbid conditions such as
obesity5.
Impulse oscillometry (IOS) is a method that allows passive measurement
of the airway mechanics of the airways by using sound waves. The
technique does not require cooperation and the measurements are taken
during tidal breathing. Airway resistance at different sound frequencies
measure different parts of the airway. Measurements at low frequencies
reflects both the central and peripheral airways while measurement at
higher frequencies reflect the larger airways thus allowing prediction
of the resistance and reactance of the small airways which are known to
be primary area of involvement in asthma6, 7.
The aim of this study was to compare airway resistance between normal
weight and overweight/obese children using IOS.