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Vulnerability to smoking “Just one cigarette in childhood can lead to later addiction, says study”
Three news stories were looked at from one national broad sheet and two online news channels. All appeared on 25th March. All three focussed on reported findings that children who reporting smoking one cigarette at age 11 were twice as likely as those who have never smoked to take up smoking at a later age, even if they had not smoked for several years in the interim. The results of this study indicate the suitability of substance use prevention aimed at younger age groups.
The reports were based on a study funded by Cancer Research UK and published in the journal Tobacco Control1. The researchers examined the development of smoking behaviour in adolescents who at age 11 had tried smoking cigarettes just once. The study utilised data from the HABITS (Health and Behaviour in Teenagers) project, a five year prospective study in a socioeconomically and ethnically diverse population. A total of 5863 students from across 36 London schools took part in the HABITS study, a five year cohort study with data collected annually between 1999 and 2003. Every year across the five years of secondary school from school year 7 (age 11-12) to year 11 (age 15-16) students completed a questionnaire in the classroom and provided a saliva sample for a cotinine assay (a sensitive measure of nicotine intake). The results showed that 20% of year 7 “one time triers” became current smokers for the first time in year 10 (age 14-15) compared with 10% (146) of year 7 never smokers. No further smoking beyond the initial cigarette had been reported by the respondents in the intervening years and therefore current cigarette use was not reported until several years after the first cigarette. By year 11 (age 15-16) new current cigarette use had equalised across the year 7 “one time triers” 12% (10) and never smokers 11% (131).
The main results of the study were reported accurately in all three news items. However, only the national newspaper conceded that the study did not imply all pupils who tried an early cigarette were likely to become smokers. This was only implied in the online reports. One news article provided a response to the findings by a member of the smokers’ group, Forest and a member of the anti-smoking group, Ash.
The researchers acknowledge the limitations of their study. Firstly, smoking behaviour was self-reported. Secondly, the analyses in the current paper are restricted to those pupils who provided smoking data at each year of the study (only 34% of the full sample) and caution should be taken in concluding that the non-significant result in year 11 signifies that the “sleeper effect” does not extend for more than three years. Finally, there may be concern regarding the generalisability of the results. The schools studied were all based in London.
None of the news items reported on these limitations, focusing instead on the link between early experimentation and smoking in later life. Headlines suggesting that the results concentrated upon the effects of ‘one [cigarette] puff’, or that one cigarette “can lead to later addiction” were not supported by the original article. It is also important to note that by the time they reached school year 11 (age 15-16) there was no difference in smoking rate between earlier “one time triers” and abstainers. This may suggest that year 7 smokers have earlier exposure to cigarettes and/or greater opportunity to use rather than early smoking causing neurochemical changes. Studies show that early initiation of any substance use leads to greater likelihood of substance dependence in later life so an important follow up to this research would be to analyse levels of dependence in year 11 smokers as they progress into adulthood. This data would provide a greater understanding of the public health implications (if any) of early initiation of smoking.
Title, Authors and Source?
Fidler JA, Wardle J, Henning Broderson N, Jarvis MJ, West R (2006) Vulnerability to smoking after trying a single cigarette can lie dormant for three years or more. Tobacco Control 15: 205-209. Available from http://www.bmjjournals.com/cgi/reprintform.
What were the study objectives?
To examine the development of smoking behaviour among adolescents who, at age 11, had tried cigarettes just once.
What was the nature of the evidence?
The evidence is developed from the HABITS study, a five year cohort study involving 5863 students from 36 London schools. Students from year 7 to year 11 completed a questionnaire on a yearly basis and provided a saliva sample for a cotinine assay. Schools were selected from a sampling frame designed to produce a socioeconomically and ethnically diverse sample. Parents were given the option to withdraw their child, and students could withdraw themselves from the study which was approved by University College London / University College London Hospital Ethics Committee. At baseline 84% of those registered at the 36 schools took part; 10% were absent on the day of data collection and 5.5% opted out. Response proportions ranged from 74-85% throughout the study. Current smokers were defined as reporting smoking cigarettes sometimes or more frequently, “one time triers” describes those having only ever smoked once, and non-current smokers included never smokers, one time triers and ex-smokers. Non-current smokers whose cotinine value was above the cut point of 15ng/ml were reclassified as current smokers. Other measures included in the analyses were: sex, area level socioeconomic deprivation, ethnicity, parental smoking and conduct problems.
What were the findings?
Students who at age 11 reported having tried smoking cigarettes just once, but were not smoking at the time, were more likely to take up smoking at a later age than those who had not tried smoking, even after a gap of up to three years of not smoking. The odds of starting to smoke at age 14 were 2.1 times greater in the age 11 “one time triers” than the non-triers, even once sex, ethnicity, deprivation, parental smoking and conduct disorder were adjusted for. However, at age 15, rates of smoking were equivalent in the age 11 “one time triers” than the non-triers.
What were the conclusions?
These data suggest a “sleeper effect” or period of dormant vulnerability. The findings have implications for understanding the development of cigarette use and for policies to reduce smoking in young people. Preventing children from trying even one cigarette may be important, and the design of interventions should recognise adolescents who have smoked just once, several years previously, as potentially vulnerable to later smoking uptake.
References
1. Fidler JA, Wardle J, Henning Brodersen N, Jarvis MJ, West R (2006) Vulnerability to smoking after trying a single cigarette can lie dormant for three years or more. Tobacco Control 15: 205-209
Media sources
ITV Online (25/5/6) One cigarette ‘means three-year cravings’ (http://www.itv.com/news/britain_614666.html |
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