Estimating the causal effect of filter ventilation levels in cigarettes on past 30-day smoking.

ABSTRACT

INTRODUCTION: Cigarettes with higher levels of filter ventilation are misperceived as less harmful and may be more appealing to consumers. Setting limits on filter ventilation has been considered as a policy, but a better understanding of any potential unintended consequences is needed. METHODS: Filter ventilation (0.2-61.1%) measured for 114 subbrands was merged with Wave 1 (2012-2013) of the Population Assessment of Tobacco Use and Health (PATH) data, restricted to adults 25+ years of age who smoked daily, and examined by quartiles. Inverse probability of exposure weights were used to estimate the causal effect of filter ventilation on past-30 day smoking at subsequent waves while accounting for potential confounders including demographics, menthol, heaviness of smoking and past quit attempts. RESULTS: Compared to those in the 1st (lowest) quartile of filter ventilation, those in the 2nd, 3rd and 4th quartiles had 1.02 (95% confidence interval 0.57, 1.82), 0.86 (0.42, 1.73) and 1.52 (0.90, 2.56) times the odds of no past 30-day smoking at Wave 2 (approximately 1 year later, p=0.163), and 1.28 (0.80, 2.07), 1.11 (0.67, 1.83) and 1.65 (1.01, 1.24) times the odds of no past 30-day smoking at Wave 4 (3 years later, p = 0.238). CONCLUSIONS: This observational study found no strong evidence of a causal effect of filter ventilation on past 30-day smoking at approximately 1 and 3 years follow-up. However, our effect size estimates were not precise and thus an increase in the ability to quit smoking due to higher filter ventilation levels cannot be ruled out. IMPLICATIONS Setting a maximum limit on filter ventilation (FV) in cigarettes could address the misperception that highly ventilated cigarettes are less harmful and the link between FV and lung adenocarcinoma. It is important to understand whether such a policy would have unintended consequences on longer-term smoking behavior. We found no strong evidence that FV affects past 30-day smoking 1-3 years later, but could not rule out the possibility that higher FV increases cessation rates. If future studies confirm these epidemiologic findings, this could mean that setting a limit on FV would not lead to reductions in the ability to quit smoking.