Results of a Portuguese study suggest that, contrary to expectations, obesity is not associated with an increased risk of asthma.
For their study, Dr Pedro Moreira and colleagues from the University of Porto examined data on nearly 40,000 adults who took part in a national health survey in Portugal between 1998 and 1999.
Each participant was asked about their social and demographic characteristics, weight and height, and whether or not they had experienced asthma symptoms in the past 12 months.
The researchers found that, surprisingly, asthma was slightly more prevalent in people who were underweight than in normal weight, overweight or obese individuals.
Although this association disappeared after taking into account age, smoking habits, education, income, physical activity and residential area, the researchers still found no association between increasing weight and a higher risk of asthma.
“Although the results from several?studies suggest that obesity antedates [precedes] asthma, in the present study obesity was not related to asthma occurrence,” Dr Moreira and his team write in the journal Allergy.
They add that further research is necessary to confirm their findings and to study whether race, genetics and environment can influence the risk of asthma among overweight and obese individuals.