Lisa Henriksen, PhD, and colleagues from the Stanford Prevention Research Center have conducted the first ever longitudinal study investigating the causal link between exposure to tobacco advertising at the point of sale (POS) and youth smoking. Results of the three-year study, published in the August 2010 issue of Pediatrics, indicate that the odds of smoking initiation are significantly higher for adolescents who regularly visit convenience, liquor or small grocery stores where POS advertising is prevalent. Increasing visit frequency predicted higher odds of smoking initiation in the sample of more than 1600 California adolescents aged 11 to 14, after controlling for potential confounders. Study protocol included school-based surveys at baseline, 12 months and 30 months, and in-store audits where researchers found, on average, that a student experienced 325 tobacco brand impressions per week. A press release from EurekAlert.org quoted Henriksen as saying, “I was surprised by the sheer number of cigarette brand impressions in the signs and displays in convenience stores near schools…The exposure is unavoidable. It’s impossible to miss.” See the free full text article here.