A new study found that roughly one-third of young adults are medically vulnerable to developing severe complications from COVID-19. The most significant risk factor appeared to be smoking. Researchers from the University of California, San Francisco, reviewed the answers of 8,400 people ages 18 to 25 who participated in the National Health Interview Survey and compared them with risk indicators of developing severe symptoms of COVID-19.

Those risk factors include heart conditions, diabetes, asthma, immune conditions, liver conditions, obesity, and smoking.

They found that 32% of the group was at risk of being hospitalized or needing intensive care because of the coronavirus. When they removed smokers from the list, the percentage of at-risk people dropped to 16%.

The researchers said one way to decrease your risk of developing severe complications from COVID-19 is to quit smoking.