Smoking less doesn’t help, study says ‘social smokers’ 8.6 times likely to die of lung cancer than non-smokers
Many consider ‘light’ smoking to be low risk. A research team, however, warns that even if people smoke a few cigarettes a day, they may not be able to escape the health risks associated with smoking, which includes lung disease and lung cancer. They found that “social smokers” -- those who smoke less than 10 cigarettes a day -- 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. The analysis also reveals that the risk of lung cancer death for social smokers is not substantially lower than heavier smokers.
The findings, presented at the European Respiratory Society International Congress, suggest that cutting down or combining fewer cigarettes with vaping, is no substitute for quitting, caution experts.
“Previous research has shown that the number of current smokers is going down in the US, but the proportion of social smokers, that is, those smoking less than 10 cigarettes per day, is increasing. For example, the proportion of smokers smoking less than 10 cigarettes per day in the US has increased from 16% to 27%. So, we wanted to study the risks of dying from respiratory diseases and lung cancers to social smokers compared to people who don’t smoke and compared to heavier smokers. In our study, we 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 to non-smokers,” study author Dr Pallavi Balte from the Columbia University Irving Medical Center, New York, told MEA WorldWide (MEAWW). She adds, “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.”
The study included 18,730 people selected from a multi-ethnic sample of the general US population with an average age of 61 (56% women, 69% White, 13% current smokers). The authors 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% and the proportion who died of lung cancer was 0.6%. Among social smokers, around 3.3% died from respiratory diseases and 4.7% died from lung cancer. For heavy smokers (people who smoked more than 20 cigarettes a day), these proportions were 10.1% and 12.9%, respectively.
The authors 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. The analysis reveals that 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. “The risks of respiratory and lung cancer mortality associated with less than 10 cigarettes per day smoking were 49% and 71%, of the risks of 20-plus cigarettes per day smoking. Results were slightly attenuated after adjusting for smoking duration,” the findings state.
Based on the current evidence, Dr Balte emphasizes that smoking is dangerous, regardless of whether a person is a heavy smoker or a social smoker. “No amount of smoking is safe. Therefore, regardless of whether you are a heavy smoker or a social smoker, if you don’t want to die of lung cancer or respiratory disease, the best action is to quit completely. However, this does not mean that we should not encourage heavy smokers to reduce the amount of cigarettes smoked per day. Smoking reduction is an important first step to smoking cessation,” she told MEAWW. The research team continues to study the effects of social smoking as well as investigating the effects of new habits such as vaping.
Jørgen Vestbo, chair of the European Respiratory Advocacy Council and professor of Respiratory Medicine at the University of Manchester, UK, who was not involved in the research, explains that while the proportion of people who smoke habitually is falling in many countries, one 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. We need to do all we can to support smokers to quit completely using evidence-based means, for example with access to support services, and nicotine patches or gum,” writes Vestbo.