New research underscores the harms of e-cigarettes, showing that vaping increases the risk of asthma in teens who have never smoked cigarettes.

Although e-cigarettes have fewer toxins than regular cigarettes, they still contain a mixture of harmful chemicals and raise the risk of respiratory diseases, researchers say.

"Increasing knowledge about the harmful effects of e-cigarette use, implementing stricter regulations, and promoting alternative coping mechanisms for mental health are potential interventions to mitigate e-cigarette use," lead author Taehyun Roh, of Texas A&M University, said in a school news release.

Asthma causes wheezing, breathlessness, chest tightness and coughing. It can be controlled by taking medicine and avoiding the triggers that can cause an attack, according to the U.S. Centers for Disease Control and Prevention.