Tobacco promotion and the initiation of tobacco use: assessing the evidence for causality.

OBJECTIVE: We sought to determine whether there is evidence of a causal link between exposure to tobacco promotion and the initiation of tobacco use by children.
METHODS: We conducted a structured search in Medline, PsycINFO, and ABI/INFORM Global to identify relevant empirical research. The literature was examined against the Hill epidemiologic criteria for determining causality.
RESULTS: (1) Children are exposed to tobacco promotion before the initiation of tobacco use; (2) exposure increases the risk for initiation; (3) there is a dose-response relationship, with greater exposure resulting in higher risk; (4) the increased risk is robust; it is observed with various study methods, in multiple populations, and with various forms of promotion and persists after controlling for other factors; (5) scientifically plausible mechanisms whereby promotion could influence initiation exist; and (6) no explanation other than causality can account for the evidence.
CONCLUSIONS: Promotions foster positive attitudes, beliefs, and expectations regarding tobacco use. This fosters intentions to use and increases the likelihood of initiation. Greater exposure to promotion leads to higher risk. This is seen in diverse cultures and persists when other risk factors, such as socioeconomic status or parental and peer smoking, are controlled. Causality is the only plausible scientific explanation for the observed data. The evidence satisfies the Hill criteria, indicating that exposure to tobacco promotion causes children to initiate tobacco use.