Heavy smokers 89% more likely to die with coronavirus, study suggests

Alexandra Thompson
·4 min read
cigarette in the hand
Smokers are at greater risk of hospitalisation and death with the coronavirus, research suggests. (Stock, Getty Images)

Heavy smokers are 89% more likely to die following a coronavirus diagnosis, research suggests.

Early in the outbreak, the UK’s chief medical adviser Professor Chris Whitty stressed “if you are going to give up smoking, this is a very good moment to do it”.

Health secretary Matt Hancock also warned “it is abundantly clear from the research into previous coronaviruses that smoking makes the impact of a coronavirus worse”.

Feeling there was little research to back up these claims, medics from The Cleveland Clinic in Ohio and Florida analysed more than 7,000 coronavirus patients.

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Results revealed those who smoked for more than 30 years were over twice as likely to be hospitalised as the patients who had never lit up.

These heavy smokers were also 89% more likely to die with the coronavirus.

Unable to marshal the right cells and molecules to fight off the invader, the bodies of the infected instead launch an entire arsenal of weapons — a misguided barrage that can wreak havoc on healthy tissues, experts said. (Getty Images)
Smoking suppresses the immune system, potentially leaving it less able to fight off the coronavirus. (Stock, Getty Images)

A small study of 102 lung cancer patients has previously suggested those who smoked for 30 years had worse coronavirus outcomes than those who did so for 20 years.

“To our knowledge, no studies have assessed the cumulative effect of smoking over time, as measured by pack-years,” the Cleveland medics wrote in the journal JAMA Internal Medicine. Pack-years was defined as the number of years smoking.

The scientists therefore analysed adults with “full smoking information” who tested positive for the coronavirus between March and August.

“The findings showed a dose-response association between pack-years and adverse COVID-19 [the disease caused by the coronavirus] outcomes,” wrote the medics.

“The results of this study suggest cumulative exposure to cigarette smoke is an independent risk factor for hospital admission and death from COVID-19.”

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The team believes this risk may be “mediated in part by comorbidites”.

Smoking raises a person’s risk of cancer, heart attacks and chronic obstructive pulmonary disease, to name a few conditions. These disorders have been linked to more severe coronavirus complications.

The medics acknowledged gauging smoking status from electronic medical records may be an imperfect method, potentially causing former-smokers to be classed as never-smokers.

“Nevertheless, we have demonstrated in this single central registry of patients who tested positive for COVID-19 that increased cumulative smoking was associated with a higher risk of hospitalisation and mortality from COVID-19 in a dose-dependent manner,” they added.

Watch: Can you catch coronavirus twice?

Why are smokers at greater risk of coronavirus complications?

Smoking damages the lungs, reducing their function.

“Lungs naturally produce mucus, but people who smoke have more and thicker mucus that is hard to clean out of the lungs,” according to Quit.org.

“This mucus clogs the lungs and is prone to becoming infected.

“Smoking also affects the immune system, making it harder to fight infection.”

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In severe cases, the coronavirus can spread from the respiratory tract to the air sacs in the lungs, where gas exchange takes place.

The air sacs then become inflamed and filled with fluid or pus, making it harder to draw in air.

This can cause oxygen levels in the blood to fall dangerously low and carbon dioxide to accumulate.

“Stopping smoking also helps improve heart and lung conditions, wound healing and many other health conditions, which will carry on at the same time as [the coronavirus],” Dr Charlie Kenward, a Bristol GP, has previously said.

“Stopping smoking remains the single most effective thing people can do to improve their and their family’s health both now and in the future.”

While in-person stop-smoking services may have shut up shop, the NHS and Action on Smoking and Health (Ash) have tips on how to combat the habit.

Quitting smoking is said to have immediate benefits, with lung health and breathing both improving relatively quickly.

It is unclear, however, whether a former-smoker has the same low coronavirus complication risk as a never-smoker.

Watch: Can you catch coronavirus twice?