Study: Smoking Habits Create Greater Risk for Severe COVID-19 in Young Adults Than Asthma, Obesity

Contrary to earlier data, a new study from the University of California at San Francisco (UCSF) suggests that younger age may not reduce the severity of coronavirus disease 2019 (COVID-19).

According to a press release from UCSF, data from the CDC has found that although patients aged 65 years and older are more likely to be hospitalized than younger people, the new study found that the gap is narrowing. For the week ending April 18, there were 8.7 hospitalizations per 100,000 people between ages 18 and 29 years, compared with 128.3 per 100,000 for patients over 65 years of age. For the week ending in June 27, however, the numbers were 34.7 and 306.7, respectively, demonstrating a 299% increase in hospitalizations for young adults.

The researchers at UCSF determined patient vulnerability by referencing indicators identified by the CDC, including heart conditions, diabetes, current asthma, immune conditions, liver conditions, obesity, and smoking within the previous 30 days. Medical vulnerability was assessed according to each indicator, so for example, 100% of smokers were vulnerable for severe COVID-19.

Perhaps most notably, the investigators found that medical vulnerability stood at 16.1% for the 6741 non-smokers included in the study, compared with 31.5% for the full sample of 8405 young adults, including smokers.

“Recent evidence indicates that smoking is associated with a higher likelihood of COVID-19 progression, including increased illness severity, ICU admission, or death,” said first author Sally Adams, PhD, in a statement. “Smoking may have significant effects in young adults, who typically have low rates for most chronic diseases.”

These concerns are compounded by recent evidence that young adults are beginning to smoke at higher rates than adolescents, which is a reversal of previous trends, according to the press release.

“The risk of being medically vulnerable to severe disease is halved when smokers are removed from the sample,” said senior author Charles Irwin Jr, MD, in a statement. “Efforts to reduce smoking and e-cigarette use among young adults would likely lower their vulnerability to severe disease.”

Interestingly, the researchers found gender differences among 5 vulnerability indicators. Women were more likely to have asthma (10% vs 7.3%), to be obese (3.3% vs 2.6%), and to have immune conditions (3.2% vs 1.6%). However, they found that significantly fewer young women smoked, which resulted in an overall medical vulnerability of 29.7% compared with 33.3% for young men.

REFERENCE

1 in 3 Young Adults May Face Severe COVID-19, UCSF Study Shows [news release]. University of California at San Francisco; July 12, 2020. https://www.ucsf.edu/news/2020/07/418081/1-3-young-adults-may-face-severe-covid-19-ucsf-study-shows. Accessed July 16, 2020.