Obesity is now considered a global health epidemic, affecting millions of people worldwide. In morbidly obese patients, the extra weight has taken a toll on their overall health, including predisposing them to cardiovascular disease, type 2 diabetes, certain cancers, and respiratory issues. However, breathing issues in obese people may be reversed and relieved, thanks to weight loss surgery.
Weight loss surgery or bariatric surgery is recommended to help obese people lose weight. Now, a team of researchers sheds light on the effect of weight loss surgery on respiratory issues among obese patients, citing that the surgery appears to reverse some of the negative effects of obesity on the respiratory system. Their study, 'Lung Parenchymal and Tracheal CT Morphology: Evaluation Before and after Bariatric Surgery', is published in the journal Radiology.
Axial unenhanced inspiratory CT images of the lungs in 51-year-old woman (a) before and (b) 6 months after bariatric surgery with 31-kg weight loss (body mass index decrease, 36.1%). The mosaic attenuation seen before surgery resolved after surgery. Image Credit: Radiological Society of North America
Obesity’s impact on the lungs
Previous body of evidence has shown that obesity harms the respiratory system, including compromising airway resistance, increasing respiratory work, and reduces respiratory muscle strength. All these factors contribute to restrictive pulmonary function impairment, which can restrict lung expansion, and eventually lead to decreased lung volume and inadequate ventilation and oxygenation.
Doctors use CT scan as an imaging technology to capture detailed images of the lungs and airways, showing a glimpse of obesity’s effect in the respiratory system. Today, there is still a limited number of CT studies that provide an evaluation of obesity’s impact on the airway and the lungs.
The researchers wanted to determine if the respiratory system changes are permanent or can be reversed after losing weight.
Bariatric surgery and patent airways
To arrive at the study findings, the team studied the changes in the respiratory tracts of 51 obese patients who had weight-loss surgery or bariatric surgery, a treatment recommended for obese patients who didn’t respond to other weight loss treatments. This procedure involves reducing the stomach size to accommodate lesser food intake and promote weight loss.
In the study, all of the participants who had weight loss surgery lost a mean body mass index of about 10.5 kg/m2. To see the respiratory status of these patients, the team used a CT scan to measure the size and shape of the trachea and evaluate for air trapping, also called gas trapping, which is the abnormal retention of air in the lungs caused by the inability to exhale completely. This condition results in a reduction in lung function, and a sign of obstruction in the small airways.
When the team compared CT results before and after the weight loss surgery, they found that the surgery and the resulting weight loss were tied to structural and morphological changes in the lungs and trachea. There was reduced air trapping, which is a strong predictor of improvement in breathing issues or difficulty of breathing, and lower incidence of tracheal collapse.
“For the first time, this study has demonstrated changes in the CT morphology of large and small airways that improve when individuals lose weight. These features correlate with an improvement in patient symptoms,” Dr. Susan J. Copley, a thoracic radiologist at Hammersmith Hospital in London, part of Imperial College Healthcare NHS Trust, said.
Reversible respiratory impact
The study shows that the respiratory issues experienced by obese individuals are reversible with weight loss. Losing weight has many health benefits, including lower risk of cardiovascular disease, insulin sensitivity, better mobility, reduced cancer risk, and now, reversing breathing issues.
While there is a need for further research to unravel the connection between CT features and biomarkers of inflammation, the study highlights CT’s promise as a component in the work-up of obese patients.
According to the World Health Organization (WHO), more than 650 million people were obese worldwide in 2016 and the number of obese people nearly tripled since 1975. Obesity is preventable and treatable, with many weight-loss treatments used to maintain a healthy weight. These include living a healthy lifestyle, eating a well-balanced diet, and engaging in moderate exercise for 150 minutes each week.
Lung Parenchymal and Tracheal CT Morphology: Evaluation before and after Bariatric Surgery Susan J. Copley, Lalani Carlton Jones, Neil D. Soneji, Jonathan Cousins, Anthony Edey, Ahmed R. Ahmed, and Athol U. Wells, https://pubs.rsna.org/doi/10.1148/radiol.2020191060