Living in a smoking household and having peers who smoke are key factors associated with children smoking, a cohort study has found.

The investigators analysed data on 11,577 teenagers in the Millenium Cohort Study, a birth cohort of children born between September 2000 and January 2002 in the UK.

As well as the smoking history of the participants, the smoking status of caregivers and friends and information about maternal smoking during pregnancy and exposure to smoking in the same room were also recorded.

After adjustment for survey weighting, 16.0% (95% CI: 14.7-17.3%) of 13 and 14 year olds had ever smoked by the time they were early teens. Extrapolating these figures nationally, this equates to 228,136 teenagers in this age group in the UK.

Moreover, 2.8% (95% CI: 2.0-3.6%) of early teens were current smokers, equating to 39,653 nationally. 

Children who reported that their current caregiver smoked were more than twice as likely ever to have smoked (26.0% vs 10.9%); adjusted odds ratio (AOR) 1.69 (95% CI: 1.38-2.06).

Among children who reported that at least some of their friends smoked, 35.1% had tried smoking, compared with 4.0% of those reporting no smoking among their friends; AOR 10.35 (95% CI: 8.35-12.81).

Current smoking was also more common among children whose caregivers currently smoked compared with those whose caregivers did not smoke (4.9% vs 1.2%) AOR 1.92 (95% CI: 1.16-3.19).

Reporting that at least some of their friends smoke, or not answering this question, was also associated with being a current smoker; AOR 22.29 (95% CI: 4.91-101.21) and AOR 9.21 (95% CI: 1.64-51.78) respectively. However, the confidence intervals were wide.

Children exposed to smoking in the same room were more likely ever to have smoked compared with those who were never exposed (20.3% vs 10.3%); AOR 1.55 (95% CI: 1.21-1.98).

Those whose mother smoked during pregnancy were more likely to smoke or have smoked than those whose mother did not. For example, 5.2% of children whose mother smoked during pregnancy were current smokers as early teens compared with 0.9% of children whose mother never smoked during pregnancy; AOR 2.16 (95% CI: 1.42-3.26).

Earlier age of first smoking was associated with continuing to be a current smoker.

‘Our data highlight the “transmissible” nature of the tobacco epidemic in young people and support the need for further urgent and comprehensive action on smoking to protect children,’ the study authors state.

The authors also conclude that the promotion of smoke-free homes has the potential to reduce youth smoking, and that tackling smoking in pregnancy can also reduce child smoking uptake. 

Dr Peter Saul