Weight loss surgery could actually reduce asthma attacks in obese people, promising new research has found.

The study found that the risk of an emergency room visit or hospitalization for someone with an asthma attack was slashed in half after bariatric or weight-loss surgery, and that risk stayed lower for at least two years, according to the study as reported by HealthDay News.

Study lead author Dr. Kohei Hasegawa, who is an attending physician in the Massachusetts General Hospital’s emergency department in Boston, said the study didn’t have specific information on the weights of the patients before and after the surgery, relying on the weight-loss surgery to demonstrate substantial weight loss.

The research indicates that losing a lot of weight — although it’s not clear exactly how much — is linked to a greater reduction in flare-ups of asthma. What is not clear is whether losing larger amounts of weight — or smaller — could reduce the amount of asthma attacks as well or more significantly.

The U.S. National Hearth, Lung, and Blood Institute says that 25 million people in the United States has asthma, which is characterized by inflamed and narrowed airways, and can result in difficulty breathing, as well as coughing and wheezing.

Weight-loss surgery is generally only recommended to people who have severe obesity. There are three types that are usually used: gastric bypass, gastric sleeve, and the lap band, with the first two procedures typically being the most effective. The lap band reduces excess weight by about 40 percent compared to 70 to 80 percent for the other two procedures, according to the report.

The findings were published in the Journal of Allergy and Clinical Immunology.