Mass media and smoking: cause and cure?

Smoking

Do mass media anti-smoking campaigns work? A recent Cochrane systematic review evaluated the evidence from controlled trials of mass media interventions on tobacco cessation.

Not surprisingly, the reviewers found huge variation between the studies in the types of campaign they evaluated, and how they measured success.

A key difficulty with this type of research is conducting a fair comparison between the intervention and the alternative.  By their very nature, it is hard to control who is exposed to mass media campaigns, and it is equally hard to ensure that the comparison groups are similar.

Methods

The reviewers addressed this problem by looking for studies that compared geographical regions in which one region received exposure to a campaign whilst another did not.  Studies that did not conduct a direct comparison like this were excluded.

They found studies evaluating eleven different campaigns, reporting a range outcomes, including quit rates and amount of tobacco consumption.  The reviewers concluded:

Tobacco control programmes that include mass media campaigns may change smoking behaviour in adults, but the evidence comes from studies of variable quality and scale. The specific contribution of the mass media component is unclear.

Comments:

  • The review is not exactly clear which studies were included!  The PRISMA flow diagram mentions three, whilst up to 8 are described in the results narrative.
  • Many of the studies were assessed as having a high risk of bias.
  • There was clear evidence of confounding from other events in many of the studies.

Did advertising make them start smoking in the first place?

Notwithstanding the instinctive temptation to answer in the form “Do bears relieve themselves in arboreal settings?”, previous reviews have shown that exposure to tobacco advertising is a risk factor for smoking in children and young people.

A new cohort study in BMJ Open addresses the association between young people starting to smoke and their exposure to tobacco advertising.

The researchers surveyed 3,415 German students aged between 10 and 15 from 29 schools, stratified accQuit smokingording to socio-demographic status.  They measured how much they had been exposed to tobacco advertising by asking them if they recognised a series of advertising images.  They compared this with how many students ended up smoking after 30 months.

The researchers found that the more children had been exposed to tobacco advertising, the more likely they were to smoke.  This association was observed at baseline, follow-up and after adjustment for other factors. The researchers estimated that the impact on smoking behaviour was in a risk ratio of 1.38 (95% CI 1.16 to 1.63) for every 10 instances of exposure to tobacco advertising.

Comments

  • This relied on self-reports, where students reported their own levels of smoking
  • There was a very high drop-out rate and a small sample size to begin with.  Further studies are needed to investigate this relationship.

References

  1. Bala MM, Strzeszynski L, Topor-Madry R, Cahill K. Mass media interventions for smoking cessation in adults. Cochrane Database of Systematic Reviews 2013, Issue 6. Art. No.: CD004704. DOI: 10.1002/14651858.CD004704.pub3
  2. Morgenstern M, Sargent JD, Isensee B, et al. From never daily smoking in 30 months: the predictive value of tobacco and non-tobacco advertising exposure. BMJ Open 2013;3:e002907. doi:10.1136/bmjopen-2013-002907