New research published in the Journal of Adolescent Health found that one in three young adults is at risk of severe Covid-19, and smoking plays a big part in that risk.

Researchers at the University of California, San Francisco, looked at more than 8,000 participants ages 18 to 25 who had participated in the National Health Interview Survey to see what their medical vulnerability to severe Covid-19 was in relation to risk indicators that had been set out by the US Centers for Disease Control and Prevention, including health conditions and smoking habits.

The researchers found 32% of the total study population were medically vulnerable for severe Covid-19. However, when the group of participants who smoked cigarettes or e-cigarettes were taken out of the analysis, the medically vulnerable percentage decreased by half, to 16%.”The difference between estimates is driven largely by the sizable portion of young adults who reported that they engaged in past 30-day smoking (1 in 10) and past 30-day e-cigarette use (1 in 14),” the report said. “By contrast, relatively fewer young adults reported medical conditions identified by the CDC as conferring severe illness risk.”

Get the full story at cnn.com.