- Fatty tissue can deposit on the walls of the lungs in overweight and obese people
- This alters the structure of the airways and increases the risk of respiratory disorders like asthma
- Reducing body weight and maintaining a low body mass index (BMI) can prevent excess fat build up in the lungs and keep asthma at bay
accumulation in the airway walls of the lungs, especially in overweight and
obese individuals has been reported for the first time in a study conducted by
a team of researchers in Australia.
Although it has been observed for a long time that respiratory disorders such as asthma are more prevalent in overweight and obese individuals, the exact reason was not known, until now. This new study indicates that fatty tissue deposition alters the structure of the airways of the lungs, thereby increasing the risk of asthma.
The study, published in the European Respiratory Journal, was led by John Elliot, who is a Senior Research Officer at the Sir Charles Gairdner Hospital in Perth, Western Australia. The senior author of the paper was Dr. Peter Noble, BSc, PhD, who is an Associate Professor and Director of Research at the School of Human Sciences, University of Western Australia in Perth, Western Australia.
Salient Features of the Study
- First study to show fat accumulation in the walls of the lungs and airways
- Structure of the lungs and airways was studied to find any changes in patients with asthma
- Correlation between fat accumulation in the airways and body mass index (BMI) was investigated
- 52 post-mortem lung tissue samples from the Airway Tissue Biobank were used in the study, which included the following:
- 15 samples were obtained from individuals who didn't have asthma
- 21 samples were obtained from asthma patients who had died of other causes
- 16 samples were obtained from asthma patients who had died of asthma
- Structures of 1,373 airways were studied by microscopy
- Fat accumulation in the tissue samples was detected and quantified
- Quantity of fat deposition was compared to the BMI of each individual
- The amount of fat deposition increased with increasing BMI
- Increased fat deposition altered the airways that led to inflammation in the lungs
He adds: "This study suggests that another mechanism is also at play. We've found that excess fat accumulates in the airway walls where it takes up space and seems to increase inflammation within the lungs. We think this is causing a thickening of the airways that limits the flow of air in and out of the lungs, and that could at least partly explain an increase in asthma symptoms."
Future PlansThe research team plans to develop new ways to detect and quantitate fatty tissue deposited in the lungs and confirm its link with respiratory diseases and whether the pathologic changes could be reversed by weight loss therapy.
Concluding RemarksProfessor Thierry Troosters, President of the European Respiratory Society, who was not involved in the study, says: "This is an important finding on the relationship between body weight and respiratory disease because it shows how being overweight or obese might be making symptoms worse for people with asthma. This goes beyond the simple observation that patients with obesity need to breathe more with activity and exercise hence adding to their ventilatory burden. The observation points at true airway changes that are associated with obesity."
He concludes: "We need to investigate this finding in more detail and particularly whether this phenomenon can be reversed with weight loss. In the meantime, we should support asthma patients to help them achieve or maintain a healthy weight."
Funding SourceThe study was funded by the Sir Charles Gairdner Hospital, the Osborne Park Health Care Group Research Advisory Committee, the Western Australian Department of Health, and the National Health and Medical Research Council of Australia.
- Fatty Airways: Implications for Obstructive Disease - (http://dx.doi.org/10.1183/13993003.00857-2019)