Obsesity is a risk for asthma and wheeze but not airway hyperrespsonsiveness 2001; 56:4-8
Obese people are probably being overdiagnosed with asthma, while thin people are probably not being diagnosed enough, suggests a study in Thorax.
To find out whether the much reported rise in asthma was linked to increasing rates of obesity, researchers investigated almost 2000 adults between the ages of 17 and 73. Asthma diagnoses and weight measurements were recorded, and an airways responsiveness challenge test was carried out to detect signs of asthma.
Once all the other confounding factors had been eliminated, the results showed that obese people were twice as likely to be diagnosed with asthma, but they were not twice as likely to have overly responsive airways, a sign of asthma. Obese people were more "breathless" than people of normal weight, but other measures of lung function were no different.
But those who were underweight were more likely to be short of breath, increased airway responsiveness, and reduced measures of lung function.
The authors conclude that although people with obesity reported more wheeze and shortness of breath, true signs of asthma were not in evidence, unlike those who were underweight. They suggest that the breathlessness may be because of the increased effort required for breathing in those who are overweight, and that this is being misdiagnosed as asthma.
Contact:
Linda Schacter, Institute of Respiratory Medicine, University of Sydney, Sydney, Australia.
Tel: + 61 3 9496 3688
Fax: + 61 3 9496 5124
lindams@bigpond.com
Journal
Thorax