What is the fine-grained topic of the following text: ​It's long been understood that obesity is linked to asthma in adults, but a new study in the December 2018 Pediatrics, "Being overweight or obese and the development of asthma," shows that an estimated 23 percent to 27 percent of new asthma cases in obese children are directly attributable to obesity. Only return the topic.
The link between obesity and development of asthma in children