Researchers in China, Europe, Canada, and now the United States are reporting a possible connection between smoking and an increased risk for COVID-19 infection.
When the novel coronavirus attacks the body, its main entry point is a receptor called ACE2, which is attached to the cells of our lungs, arteries, heart, kidney, and intestines. A report recently published in the American Journal of Respiratory and Critical Care Medicine states that smokers have more of these activated ACE2 gene receptors than those who have never smoked. This may make cigarette and marijuana smokers more vulnerable to COVID-19 infection.
But, the COVID-19 patients treated in local emergency rooms and hospitals do not reflect this clinical data.
“Our data is inconsistent with the numbers coming out of China and Europe, where smoking rates are much higher in the general population,” says Mehdi Mirsaeidi, M.D., a pulmonary and critical care specialist with the University of Miami Health System. “In the U.S., we are not yet sure if their findings are valid among our population.”
What do UHealth doctors and researchers know?
“The expression of gene receptor AEC2 definitely does increase with smoking,” Dr. Mirsaeidi says, “but that may or may not cause the COVID-19 virus to attach. This part of the association and causation is not yet proven. We know that the virus attaches to this receptor, but we don’t know if this translates to smokers having an increased risk for COVID-19 infection or death.”
Dr. Mirsaeidi reports that, at UHealth, experts studied 127 patients with COVID-19 infection. Out of those cases, 80 of them had never smoked in their lifetime (28 of them were male, 42 were female). Twenty-five of the 127 patients were former smokers. The smoking history of 17 of them was unknown. Only 5 of the 127 patients were current smokers. “So, less than 5% of the cases in our cohort were active smokers,” he says.
Out of these 127 patients, 17 of them died from COVID-19 disease and complications. Only one of those patients was a current smoker. Seven of them were former smokers, and six of them had never smoked in their lifetime. None of them reported having used e-cigarette vaporizers. Their history with smoking marijuana was not reported.
From these statistics, “Generally speaking, smokers may be at a higher risk than those who have never smoked," he says. "This doesn’t mean that most COVID-19 patients are smokers or have smoked. Smoking on its own does not appear to be a major driver for this viral infection. I can’t say that nonsmokers are safer than smokers from this virus.”
He also says that the medical community is against smoking of any kind. “That has not changed. If you’re smoking, you need to quit for many health reasons, including your cardiovascular health and the serious risk for developing chronic obstructive pulmonary disease (COPD).”
Patients with COPD have a significantly higher risk of mortality. Dr. Mirsaeidi says, “up to 90% of those with COPD currently smoke or have been smokers. The chronic damage in the lungs caused by COPD may be another reason smoking increases the risk for COVID-19 disease and, ultimately, death.
"This is just another reason every smoker should quit, particularly in the COVID-19 era.”
Dana Kantrowitz is a contributing writer for UMiami Health News.
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