Advertising and Promotion of Tobacco Encourage Smoking Among Youth: Study

B. Tobacco advertising and promotion increase tobacco use by children and adolescents

1. Cross-sectional studies

Many cross-sectional studies have found that smoking status and smoking initiation among youth are correlated with awareness, recognition, and approval of tobacco advertisements and promotions; exposure to tobacco advertisements and promotions; “receptivity” to tobacco advertising and promotion; receipt or ownership of tobacco promotional items; and a feeling that cigarette ads make them want to smoke a cigarette.13, 25, 29-38

Cross-sectional studies evaluate correlations at a single point in time. Although the correlations between smoking behavior and cigarette advertising in these studies are compelling when considering the total body of evidence — which includes many different study designs, study populations, and investigators — the cross-sectional nature of these studies does not allow a definitive conclusion about the direction of causality. For example, if a cross-sectional study shows that teenage smokers are more likely than nonsmokers to “like” cigarette ads, two explanations (with opposite directions of causality between the associated variables) are possible: a) teens who like cigarette ads are more likely to become smokers over time than teens who don’t like the ads; or b) teens who become smokers are more likely to develop a liking of the ads than teens who don’t become smokers. Longitudinal studies, which assess correlations at two or more points in time, can determine the temporal relationship between two associated variables, and hence the causal relationship between the two. Two longitudinal studies of youth smoking in relation to tobacco advertising are described below.

2. Longitudinal studies

Two important longitudinal studies followed up on earlier cross-sectional investigations. In a cross-sectional survey of 6000 primary school children (10-12 years old) in New South Wales, Australia, the children were asked whether cigarettes should be advertised. Logistic regression was used to determine the relative importance of several factors, including approval of cigarette advertising, in relation to the children’s smoking status. Approval of advertising was the second most important predictor of smoking status, after friends’ smoking behavior but ahead of siblings’ smoking behavior, amount of money available to spend weekly, sex, age, and parents’ smoking status.29

The investigators then assessed changes in smoking behavior over 12 months among these 6000 children in a longitudinal study design.39 This design allowed the investigators to assess the strength of the association between several personal and social variables and the process of adopting or quitting smoking. Four study groups were defined: a) children who became smokers (adopters); b) those who remained nonsmokers; c) those who became nonsmokers (quitters); and d) those who remained smokers. As noted by the authors, “Children who approved of cigarette advertising were twice as likely to become smokers as children who disapproved, with the smoking behaviour of those who were ambivalent about advertising falling between that of the other two groups.” The smoking adoption rate per 100 children was 27.0 for those approving of cigarette advertising, 12.1 for those not approving, and 19.3 for those who said they “don’t know,” a difference which was highly statistically significant (p < 0.001). Similarly, children who disapproved of cigarette advertising were significantly more likely to quit smoking than those who approved of it.39

Pierce and colleagues have also used both cross-sectional and longitudinal study designs to establish the relationship between cigarette advertising and smoking initiation among youth. They have defined constructs for “susceptibility to smoking” and “receptivity to tobacco marketing.” With regard to the former, adolescents with no smoking experience are asked two questions to probe the likelihood of future smoking: “Do you think you will try a cigarette soon?” and “If one of your best friends were to offer you a cigarette, would you smoke?” Any answer other than “no” or “definitely not” to both questions results in classifying an adolescent as susceptible to smoking.34

In an earlier cross-sectional study, Evans et al. defined an “Index of Receptivity to Tobacco Marketing.”34 The index was based on the total score from five items: a) whether the adolescent felt that a tobacco advertisement contained at least one of nine messages (e.g., smoking is enjoyable, it helps people relax, it helps people stay thin); b) whether the adolescent could name a cigarette brand in response to either of two questions — “What is the name of the cigarette brand of your favorite cigarette advertisement?” and “Of all the cigarette advertisements you have seen, which do you think attracts your attention the most?”; c) whether the adolescent could name a cigarette brand in response to the question “If you wanted to buy a pack of cigarettes tomorrow, what brand do you think that you would buy?”; d) whether the adolescent said “yes” to the question “Have you ever bought or received for free any product which promotes a tobacco brand or was distributed by a tobacco company?”; and e) whether the adolescent said “yes” to the question “Do you think that you would ever use a tobacco industry promotional item such as a T-shirt?”

Using data from 3,536 adolescent never-smokers from the 1993 California Tobacco Survey in a cross-sectional, logistic regression analysis, Evans et al. found that receptivity to tobacco marketing was independently associated with susceptibility to smoking, after adjustment for sociodemographic variables (including age, sex, and race/ethnicity) and perceived school performance. Adolescents who scored 4 or more on the Index of Receptivity to Tobacco Marketing were 3.91 times more likely to be susceptible to smoking than those who scored 0. Even adolescents who scored 2 on the Index were twice as likely to be susceptible.34