Does 'just one cigarette at parties' turn into a daily habit?

"One cigarette 'may lead to habit for more than two thirds of people'," reports The Guardian. The Mail Online goes further, claiming that "one puff of a cigarette is enough to get you hooked".

The research sparking these headlines used survey data from 216,314 people who were asked whether they had ever tried a cigarette and if they then progressed to regularly smoking. Around 60% of respondents had tried a cigarette and, of these, just over two thirds became regular smokers.

Although there are some limitations with this type of research – for example, it relies on people accurately remembering their history of smoking – this study adds to our understanding of the addictive nature of cigarettes. Hopefully these results will discourage people from trying smoking in the first place.

Find more advice about the risks of smoking and the support available to help you quit.

Where did the story come from?

The study was carried out by researchers from Queen Mary University of London and the University of Glasgow. No external funding was used. It was published in the peer-reviewed journal Nicotine & Tobacco Research.

This story was covered widely in the UK media and, on the whole, the statistics were reported accurately. However, despite the Mail Online's claims, the research did not confirm that "one puff" is enough to cause addiction. The researchers only asked if participants had ever tried a cigarette – not how many puffs they had.

A few of the reports went on to discuss e-cigarette use, with one stating: "Very few non-smokers who try e-cigarettes become daily vapers." However, vaping and e-cigarettes weren't discussed in this study.

What kind of research was this?

This was a meta-analysis, which is a robust way of pooling findings from multiple studies on a specific topic to see if there is a common effect.

However, the findings are only as good as the underlying research, so it's important to consider the quality of the included studies individually when deciding if a meta-analysis is reliable.

What did the research involve?

The researchers searched the Global Health Data Exchange, a large database containing health-related data, for surveys conducted between 2000 and 2016.

The surveys included in the analysis were carried out in developed countries and asked people if they had ever:

• tried a cigarette (described as "experimental smoking")
• been a daily smoker

A total of 216,314 adults from 8 surveys were included in the meta-analysis. Of the surveys, 3 each were conducted in the US and the UK, and 1 each in Australia and New Zealand. Some surveys offered a financial incentive for taking part.

The researchers also looked at whether the results may have been affected by some smokers being less likely to respond because of:

• higher smoking rates in populations such as the homeless and people with mental health problems, as they are less likely to take part in surveys
• smoking being viewed as an undesirable behaviour in the participating developed countries

What were the basic results?

Response rates to the 8 surveys varied from 45% to 88%. Out of the people who responded to the questions:

• 60.3% had tried a cigarette (95% confidence interval [CI] 51.3 to 69.3%)
• of these, 68.9% became a daily smoker (95% CI 60.9 to 76.9%).

The researchers then tested the data to see if it could have been biased because some smokers may have been less likely to respond to a survey, as discussed above. No evidence of bias was found.

How did the researchers interpret the results?

The researchers said: "The transition from trying the first cigarette through occasional to daily smoking usually implies that a recreational activity is turning into a compulsive need that has to be satisfied virtually continuously.

"The findings provide strong support for the current efforts to reduce cigarette experimentation among adolescents."

Conclusion

This meta-analysis used a large sample of data from a global database, and provides evidence of a link between trying a first cigarette and becoming a regular smoker. It also presents a potentially valuable measurement of smoking behaviour over time: the "conversion rate" from initial experimentation to daily smoking.

The study does have limitations, however:

• The surveys worded their questions differently, which means we can't be sure if everyone asked about whether they had ever experimented with smoking/tried a cigarette understood the question in the same way.
• Survey data relies on accurate – and honest – responses. People may not always remember their smoking history correctly.
• Some non-smoking respondents may have forgotten they had tried smoking. If this did happen, it means the results overestimated the proportion found to convert to full-time smokers.
• All of the surveys included were cross-sectional, meaning they took data at just one point in time. Therefore, they may not offer a true representation of people's smoking habits, which are likely to change over time.

As it stands, this research doesn't help us understand the reasons why some people who experiment with cigarettes become smokers and others don't.

Further research – using data collected over longer time periods, and taking into account smokers' mental health, family history of smoking, ethnicity and age – will help public health campaigns target specific populations that may be at increased risk of becoming smokers.