A Pragmatic Trial in the Rio de Janeiro Subway to Capture Smokers for a Quitline: Methodological Challenges and Opportunities

Abstract

According to the World Health Organization, smoking is an important cause of death worldwide. To encourage smoking cessation, persuasive messages can be used to raise smokers' risk perception. This article discusses challenges and solutions in designing a study to evaluate the effect of two different communication strategies (“gains from quitting” vs. “losses from continuing smoking”) in encouraging calls to a quitline. The authors conducted an intervention study in two subway stations for 4 weeks, considering only 1 strategy per station. Large posters containing non–age-specific images and texts, on the basis of the theme“shortness of breath,” were displayed on central dividing columns on the boarding platforms. Call rates from the selected stations, and respective rate ratios, overall and per study week, were calculated. Passengers who were smokers, exposed to the positive-content message, called on average 1.7 times more often than did those exposed to the negative-content message (p = .01). Moreover, call rate ratios did not decline over the 4 weeks of the study (p = .40). The effectiveness findings suggest that antismoking campaigns could use positive-content messages in order to recruit a larger smoker population. The proposed methodology can also be used to evaluate effectiveness of messages for “capturing” individuals with other health problems (e.g., alcohol abuse), thereby increasing its potential impact.

Acknowledgments

The authors thank the staff at Communications Unit of Rio de Janeiro Subway Company (MetrôRio), and Helena Barros, Luciana Rizzieri, and Taís Moreira from VIVAVOZ Quitline, who made this study possible. They also thank Rejane Spitz and Nilton Gamba Jr., for helping with the design of communications interventions.

This work was supported by the Brazilian Ministry of Health (953/2006) and the Brazilian National Cancer Institute (10302122087580033021830/2008).

The authors have no potential or actual relationship to individuals or organizations that could have influenced the research inappropriately.

Notes

Note. CTG = Cantagalo; ACV = Arcoverde; LE = Leme (shuttle bus service); FLA = Flamengo; CAT = Catete; GLO = Glória; SFX = São Francisco Xavier; AFP = Afonso Pena; VIS = Vila Isabel (shuttle bus service).

^a Residents/household.

^b Variable only available for head of household.

^c Mean value (in Brazilian currency, reais).

Note. This table summarizes the proposed solutions for minimizing the potential problems involving lack of homogeneity between subway stations' passengers and contamination of intervention contents between study groups, which allowed to calculate a potential unbiased call rate ratio between stations.

^a No detailed passenger profile data were available a priori for the Rio de Janeiro subway stations.

^b Excludes last stop on subway main entrances.

^a This station displayed a poster with a positive message, highlighting the gains of quitting smoking.

^b This station displayed a poster with negative message, emphasizing possible losses from not quitting smoking.

^c Smokers aged 15 years and older.

^d Total number of nonsmokers who called from positive-content station and negative-content station were, respectively, 14 and 9. Overall number of individuals who were “lost” (i.e., hung up before providing all pertinent information) was 7.

^e Call rates per 10,000 passenger-days.

^f Multiplicative interaction calculated between the variables “station” (proxy for intervention's groups) and “study week” (2nd to 4th weeks were grouped in the same category) for the call rate ratios: p = .40.

^g Confounding effects of the stratified variable (i.e., study week) were taken into account.