Social smokers just as at risk of lung cancer as those smoking 20 a day © Getty Images

Social smokers just as at risk of lung cancer as those smoking 20 a day

Published: 06th September, 2020 at 14:00
Try 3 issues of BBC Science Focus Magazine for £5!

Researchers said their 17-year-long study suggests that cutting down, or combining fewer cigarettes with vaping, is no substitute for quitting.

People who smoke socially are more than twice as likely to die of lung disease and more than eight times as likely to die of lung cancer than non-smokers, a study suggests.


The research shows that the risk of lung cancer death for “social smokers” – those who smoke fewer than 10 cigarettes per day – is not substantially lower than those who smoke more than 20 a day.

According to the researchers, their 17-year-long study suggests that cutting down, or combining fewer cigarettes with vaping, is no substitute for quitting.

The research was by Dr Pallavi Balte and Dr Elizabeth Oelsner, at Columbia University Irving Medical Centre in New York, presented at the European Respiratory Society International Congress.

Read more about smoking:

Dr Balte told the virtual conference: “Everyone knows that smoking is bad for you, but it’s easy to assume that if you only smoke a little, the risks won’t be too high.

“Previous research suggests that people are cutting down on smoking, for example in the USA the proportion of smokers smoking less than 10 cigarettes per day has increased from 16 per cent to 27 per cent. So we wanted to study the risks to social smokers compared to people who don’t smoke and compared to heavier smokers.”

The study included 18,730 people selected from a multi-ethnic sample of the general US population, with an average age of 61.

Researchers followed the people for an average of 17 years, during which time 649 died of respiratory disease and 560 died of lung cancer.

Cutting down is a step in the right direction, but it’s clear that there is no safe level of smoking
Jorgen Vestbo, University of Manchester

Among non-smokers, the proportion of people who died from respiratory diseases was 1.8 per cent and the proportion who died of lung cancer was 0.6 per cent.

Among social smokers – people who smoked fewer than 10 cigarettes a day – around 3.3 per cent died from respiratory diseases and 4.7 per cent died from lung cancer. For heavy smokers – people who smoked more than 20 cigarettes a day – these proportions were 10.1 per cent and 12.9 per cent, respectively.

The researchers calculated the death rates from respiratory disease and lung cancer and compared these rates between non-smokers, social smokers and heavy smokers.

They took account of other factors that can influence death rates, such as age, sex, race, educational attainment and body weight.

Read more about lung cancer:

They found that social smokers were 2.5 times as likely to die of respiratory disease and 8.6 times as likely to die of lung cancer, compared with non-smokers.

Social smokers had around half the rate of death from respiratory disease as heavy smokers, but their rate of lung cancer death was two thirds that of heavy smokers.

Dr Balte said: “You might think that if you only smoke a few cigarettes a day you are avoiding most of the risk. But our findings suggest that social smoking is disproportionately harmful.”

Jorgen Vestbo, chairman of the European Respiratory Society Advocacy Council and professor of respiratory medicine at the University of Manchester, was not involved in the research, but said: “Although the proportion of people who smoke habitually is falling in many countries, we should still be concerned about those who identify as social smokers.

“Cutting down on smoking is a step in the right direction, as quitting tobacco is one of the best ways to protect the lungs and our overall health, but it’s clear that there is no safe level of smoking.


“This large study is important because it shows that smoking less will probably not have the effect that people are hoping for.”

Is vaping safe?

Asked by: Stacey Hughes, Buckinghamshire

The most recent research shows that vaping is much less bad for you than smoking. If you already smoke cigarettes, then switching completely to e-cigarettes will significantly improve your health.

But smoking is so bad for you that you could switch to skydiving and still come out ahead! Skydiving every day for 70 years gives a 23 per cent chance of early death, while lifelong smokers have a 50 per cent chance of dying before 70.

The real question is: can you safely take up recreational vaping, even if you don’t already smoke? The evidence for this is much less clear. Nicotine by itself doesn’t cause cancer, and vape juice doesn’t contain any of the 70 known carcinogens that are present in tobacco.

But it does contain other chemicals, such as propylene glycol. When this is heated by the electric element in the e-cigarette, it can create formaldehyde, which is carcinogenic. The different flavour chemicals used in vape juice are all organic compounds, and these can also be altered by the heating element.

Vaping has only been around for a decade, so it is still too soon to be sure of long-term effects. Since e-cigarettes will get you hooked on nicotine just as surely as tobacco does, it doesn’t seem wise to take up a whole new addiction.


Amy BarrettEditorial Assistant, BBC Science Focus

Amy is the Editorial Assistant at BBC Science Focus. Her BA degree specialised in science publishing and she has been working as a journalist since graduating in 2018. In 2020, Amy was named Editorial Assistant of the Year by the British Society of Magazine Editors. She looks after all things books, culture and media. Her interests range from natural history and wildlife, to women in STEM and accessibility tech.


Sponsored content