Social smokers are more than twice as likely to die of lung disease and more than eight times as likely to die of lung cancer than people who do not smoke, new research suggests.
The study, presented at the European Respiratory Society International Congress, 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.
Researchers said 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.
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.
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.
Around 3.3 per cent of social smokers died from respiratory diseases and 4.7 per cent died from lung cancer.
For people who smoked more than 20 cigarettes a day these proportions were 10.1 per cent and 12.9 per cent, respectively.
Dr Balte added: “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.”