Review of 28 studies shows number of smokers among hospitalised patients is ‘lower than expected’ as expert admits the mounting findings are ‘weird’

  • UCL reviewed 28 studies from China, US, France, South Korea and the UK
  • It found smokers were less common than expected among COVID-19 patients 
  • Researchers said there data on smoking is not to a high standard and has holes
  • But it’s not the first time the unexpected link has been spotted by scientists 
  • One expert said ‘something weird is going on with smoking and coronavirus’
  • Here’s how to help people impacted by Covid-19

A review of scientific studies has added more evidence to the claim that people who smoke might have a lower risk of becoming seriously ill with COVID-19.

University College London academics looked at 28 papers and found the proportions of smokers among hospital patients were ‘lower than expected’.

One public health professor said there was ‘something weird going on with smoking and coronavirus‘ and experts are struggling to explain the connection.

One of the studies showed that in the UK the proportion of smokers among COVID-19 patients was just five per cent, a third of the national rate of 14.4 per cent.

Another found in France the rate was four times lower. In China, a study noted 3.8 per cent of patients were smokers – despite more than half of the population regularly smoking cigarettes.

When smokers do get diagnosed with the virus, however, they appear to be more likely to get so sick that they need ventilation, two studies in the review showed.

Researchers admit that hospitals are probably not recording patients’ smoking status properly, potentially because they are too busy, patients are too sick to answer, or because people lie in their answers.

But they are struggling to knock down mounting evidence suggesting an apparent protective effect given by cigarettes, which one expert today admitted was ‘weird’.

A review of five early studies on the topic last month made the exact same conclusions – that smokers may avoid serious infection, but their outlook is worse if they do.

University of College London reviewed 28 studies and found smoking rates were lower than expected among COVID-19 patients. The graph shows the smoking rate of each country against the percentage of smokers among COVID-19 patients. The lowest figure has been chosen for each country to show the stark comparison discovered by some studies

University of College London reviewed 28 studies and found smoking rates were lower than expected among COVID-19 patients. The graph shows the smoking rate of each country against the percentage of smokers among COVID-19 patients. The lowest figure has been chosen for each country to show the stark comparison discovered by some studies

The team are not the first to suggest smokers may be protected by their habit, after a slew of studies have spotted the unexpected link (stock image)

Two of the authors on the recent UCL review received research grants from smoking cessation lobbies.

Their paper was titled ‘The association of smoking status with SARS-CoV-2 infection, hospitalisation and mortality from COVID-19: A living rapid evidence review’ and was published on the study-sharing website Qeios.

David Simons and colleagues looked at 28 studies involving more than 23,000 people.

Twenty-two of the studies were conducted in China, three in the US, one in South Korea, one in France and one was an international study using mostly UK data.

Only three of them split smoking status into three parts – current, former and never smokers.

The other 25 only reported current and former smoking status, but there were questions around how many of the rest had never smoked, and how many had missing data.

‘Notwithstanding these uncertainties, compared with national prevalence estimates, recorded current and former smoking rates in the included studies were generally lower than expected,’ the study authors wrote.

Data from the US suggests that smokers appear to be less likely to test positive for SARS-CoV-2 compared with never smokers.

Rather than this reflecting likelihood of catching the virus in the first place, it is more likely to point to someone’s risk of becoming so ill they have to go to hospital. Most of the countries involved in the studies did almost all of their testing in hospitals.

But the researchers noted that smokers were more likely to be tested, possibly because their symptoms, like a cough, are more obvious due to their habit.

‘We would therefore caution against drawing any conclusion as to whether smokers are at increased risk of SARS-CoV-2 infection at this early stage,’ the UCL team said.

Two high quality studies provided zero evidence that the 657 current or former smokers with the virus were at a higher risk of ending up in hospital.

But among 1,370 people hospitalised across two other studies, smokers were 43 per cent more likely to see their disease progress to become severe than those who had never smoked.

Three studies reported death rates from COVID-19 but there ‘did not appear to be a notable difference’ between smokers and non-smokers.

However, the studies ‘did not explicitly state never smoking status’, the authors said. They implied that patients who died may have smoked in the past, but this was not clearly recorded by a doctor.

The authors concluded there is a lack of evidence that meets a high standard to definitely say whether or not smokers are at higher risk of catching the coronavirus, or having poor outcomes.

Read full article here.

Vanessa Chalmers – Daily Mail – April 28, 2020.

Want More Investigative Content?

LEAVE A REPLY

Please enter your comment!
Please enter your name here