Exposure to tobacco advertising predicted smoking adoption and continuance among German adolescents, researchers found.
In an observational, longitudinal survey, every 10 tobacco ad sightings boosted the risk of smoking in teens by almost 40%, and increased the chances of their being daily smokers by nearly a third, according to Matthis Morgenstern, PhD, of the Institute for Therapy and Health Research in Kiel, Germany, and colleagues.
Exposure to non-tobacco ads did not increase smoking risks, they reported online in BMJ Open.
The study measured the responses to six tobacco and eight non-tobacco advertisements among 1,320 sixth-to-eighth-grade students (mean age 12.3 years) who reported at baseline that they had never smoked. The students, from 21 public schools in three northern German states, indicated how often they had seen each ad.
The students were surveyed in fall 2008 and again in the spring of 2011. At followup, 5% reported they had smoked more than 100 cigarettes, while another 4.4% classified themselves as daily smokers. Among the daily smoker group, one-third were ages 14 or younger, while nearly one-quarter were 16 or older.
Every 10 additional tobacco advertising exposures increased the relative risk for smoking by 38% (95% CI, 16% to 63%, P<0.001) and for daily smoking by 30% (95% CI, 3% to 64%, P<0.05). The risk was controlled for age, gender, socioeconomic status, school performance, television time, personality characteristics and smoking status of peers and parents, the investigators stated.
One in three (406 students) said they tried smoking during the 30 months, with one in 10 (138) saying that they had smoked within the preceding month.
Billboard and TV images analyzed included those for six popular cigarette brands in Germany: Marlboro (with cowboy and horse images), F6 (sunrises), Gauloises (a couple), Pall Mall (the Empire State Building), L&M (a couple), and Lucky Strike (cigarette packs).
The eight non-tobacco product ads included those for chocolate, clothes, mobile phones, and cars. No significant association for smoking was found for non-tobacco advertising contact.
Teens were twice as likely to start and keep smoking when they saw the most tobacco ads (11 to 55) compared with when they saw the least ads (0 to 2.5). Teens saw far fewer cigarette ads than for non-tobacco products, but one tobacco ad was seen by almost half the adolescents at least once, and more than 10 times by 13% of the group, researchers reported.
Smoking among peers proved the strongest influence, researchers stated, followed by exposure to tobacco ads.
School performance among the sample was "average" for 30.6%, and "good" for 53.9%. TV screen time averaged 1 to 2 hours per day among 60.1% of participants. Students reported that 71.9% of their peers smoked, and that 56.4% of their parents were smokers.
Among the study limitations, the authors noted that 1,026 (44%) of the original 2,346 student participants dropped out. Also, the results may have been biased by unmeasured confounders, they stated, adding that the ad exposure was measured by recall, which could also have been biased.
The results support the content-specific association between tobacco advertising and smoking behavior, as well as the total ban on tobacco advertising advocated by the World Health Organization Framework Convention on Tobacco Control, they wrote.
"Data from this study support this measure, because only exposure to tobacco advertisements predicted smoking initiation, which cannot be attributed to a general receptiveness to marketing," the authors concluded.
Primary source: BMJ Open
Source reference: Morgenstern, M et al "From never to daily smoking in 30 months: the predictive value of tobacco and non-tobacco advertising exposure" BMJ Open 2013; DOI: 10.1136/bmjopen-2013-002907.