Smoking rates have dropped dramatically since their peak in the mid-1960s when 40 percent of all adults in the United States smoked, according to the National Center for Health Statistics. Current data from the US Centers for Disease Control and Prevention say the rate is 13.7 percent, but that still means 32.4 million Americans smoke. And at least 16 million are affected by smoking-related conditions such as lung cancer, heart disease, high blood pressure, diabetes, emphysema, and chronic obstructive pulmonary disease.

Smoking is also associated with vascular dementia and stroke, and with poorer outcomes for people with multiple sclerosis. "We know that smoking can damage the endothelium, the thin layer of cells that line blood vessels, which can lead to cardiovascular disease and stroke," says Philip B. Gorelick, MD, MPH, FAAN, professor of neurology at Northwestern University Feinberg School of Medicine in Chicago. "In addition, smoking causes oxidative stress and inflammation in the brain, which may contribute to cognitive impairment and dementia."

Since March, people who smoke or use tobacco products like e-cigarettes have faced a new threat: COVID-19. Not only are tobacco users at higher risk of infection, they also are more likely to be admitted to the intensive care unit, to need a ventilator, and to die of the virus, says Jonathan Winickoff, MD, MPH, professor of pediatrics at Massachusetts General Hospital, whose work includes tobacco control research for the health and well-being of children and teens. "Anything that damages the lungs creates the possibility of more illness, and that's exactly what the epidemiology of COVID-19 is showing," he says.

For instance, a meta-analysis of 19 peer-reviewed studies that included a total of 11,590 COVID patients worldwide found that smoking nearly doubled the risk of progression of COVID-19. The analysis, published in Nicotine and Tobacco Research in May 2020, also revealed that when the disease worsened, current or former smokers had more acute conditions or were more likely to die.

Another study, published online in August 2020 in the Journal of Adolescent Health, said that young adults who smoked e-cigarettes, regular cigarettes, or both were five to seven times more likely to be diagnosed with COVID-19 than nonusers.

Vapers—those who use e-cigarettes—touch their faces more often than people who don't smoke or vape, increasing the likelihood of transferring the virus from their hands to their mouths, says Dr. Winickoff. And they are more susceptible to getting infected or infecting others if they share water pipes or vape pens. "Vaping products are commonly shared among young adults," he says. "Because of that, we've seen an increase in positive cases in this group."

It's impossible to wear a mask when smoking or vaping, thus heightening the risk of being infected or infecting others. And smoking provides another potential route of infection. "If somebody has an active infection, that plume of smoke is likely filled with virus particles," says Larry B. Goldstein, MD, FAAN, chair of the neurology department at the University of Kentucky in Lexington.

Smoking increases vulnerability to COVID-19 in other ways, says Stanton Glantz, PhD, director of the Center for Tobacco Control Research and Education at the University of California San Francisco. Studies show that the coronavirus enters cells by binding to angiotensin-converting enzyme 2 (ACE2) receptors. "If you think of these receptors as doors, smokers have more of them, so there are more openings for the virus," says Dr. Glantz. "When you quit smoking, the number of ACE2 receptors goes back to normal."

Smoking also damages cilia, the microscopic hairs lining the nose and upper airways, and macrophages. Cilia are important because they catch foreign objects, such as viruses and bacteria, and push them out. Macrophages are a natural immune system in the air cells deep in the lungs, which gobble up bacteria and viruses, says Dr. Glantz. "This system is compromised in smokers."

Flavoring agents like menthol that make it easier for smokers to inhale more deeply only worsen the situation, says Dr. Winickoff. "Flavors mixed with tobacco products tend to cause more severe lung inflammation, which is exactly what's happening with COVID-19."

Given the volatile association between smoking and COVID-19, health officials say quitting is more important than ever. "There are many more tobacco-related deaths than COVID-19-related deaths, so if we could get half the world to stop using tobacco because of the pandemic, that would be one positive consequence of this terrible disease," says Dr. Winickoff.

Quitting smoking is difficult to accomplish in one attempt, says Dr. Glantz. "The strongest predictor of success in quitting is how many times you've tried," he says. Other cessation experts agree. "Every try counts," says Laura Corbin, bureau chief of Tobacco Free Florida, a state-run program in Tallahassee. "Most smokers who keep trying eventually succeed, so don't give up," she says.

Proven Ways to Kick the Habit

Whether it's your first time trying to quit smoking or your umpteenth time, these strategies can help.

Seek support. Don't go it alone, says LaToya Clark, MPH, director of the tobacco program at the Area Health Education Center (AHEC) at the University of South Florida in Tampa. "More than 90 percent of people try to quit cold turkey, and only 5 percent are successful," she says. "We know that many people want to quit, but they can't do it on their own." Every state has an 800-QUIT-NOW helpline that connects people wanting to quit with web resources, coaches, and smartphone apps. You can also visit smokefree.gov or ask your health care provider for a referral to a local cessation program. Tell your friends and family about your goal of quitting, and ask them to encourage you and keep you accountable.

Create a plan. The best tactic for you depends on how much you smoke. For light or infrequent smokers, making the home and car smoke-free could be enough to encourage quitting, says Stanton Glantz, PhD, director of the Center for Tobacco Control Research and Education at the University of California San Francisco. For people who smoke a pack a day or more, a combination of behavioral therapy and medication may be required, he says.

Consider nicotine replacements. Talk to your doctor about nicotine patches, gums, and lozenges. Do not smoke or use e-cigarettes while on nicotine replacement therapy. Several medications, including varenicline (Chantix) and the antidepressant bupropion (Wellbutrin), have been approved by the US Food and Drug Administration to help smokers quit by reducing cravings and withdrawal symptoms.

Try behavioral therapy. Trained cessation counselors can help identify triggers and ways to overcome them, says Clark, who notes that AHEC moved its group therapy sessions online because of the pandemic. "We saw an uptick in inquiries and referrals from providers about a month after our virtual sessions began," she says.

Combine approaches. The data show that smokers are more likely to quit if they incorporate counseling, social support, and nicotine replacement therapy, says Clark. "Whenever you combine therapies, the quit rate doubles or even triples."

Commit to quitting. Once you formulate a plan, stick to it. If you're consistent with a customized cessation program, you have a better chance of becoming a nonsmoker, says Dr. Glantz.