This study highlights the much stronger association between individual health risk factors and youth smoking behaviour compared to community risk factors. Two studies that have examined the relationship between tobacco outlet density or proximity and youth smoking have suggested that tobacco outlet density (but not proximity) is associated with youth smoking.21
Consistent with those studies, in the unadjusted model we saw a statistically significant association between tobacco outlet density and youth smoking, but not after accounting for additional community and individual risk factors for youth smoking. More importantly, the magnitudes of the community associations with youth smoking were small compared to individual risk factors. Thus, regardless of whether the association of tobacco outlet density reached accepted standards for statistical significance, the small potential effect across a broad range of tobacco outlet densities suggests that policies designed to lower density would have only a small impact on adolescent smoking. In contrast, the associations between team sports participation and both smoking outcomes were large enough to suggest that interventions and policies aiming to support those activities could help prevent adolescent smoking.
This study used Bronfenbrenner's Ecological Systems Theory to frame the possible joint effects of individual-level, microsystem, mesosystem and exosystem variables on youth smoking. When variables were scaled so as to compare effect sizes, our findings indicated a relative importance of individual-level variables compared to the community variables we studied. We suggest that empirical multilevel studies pay attention to estimating effects that allow for such comparisons, in addition to focusing on statistical significance. Although we found no strong associations with smoking for the community variables studied, this study does not rule out the possibility that other neighbourhood characteristics, such as measures of social capital or neighbourhood smoking, may have an important impact on youth smoking. In fact, one study using the Brofenbrenner model found that neighbourhood rates of youth smoking affected adolescent smoking trajectories, over and above individual risk factors.41
The association between some risk factors and smoking was present for trying smoking but not smoking intensity among experimental smokers, underlying the importance of modelling different smoking transitions separately. Trying smoking is strongly influenced by social risk factors (sibling smoking, friend smoking, movie smoking and team sports participation). Among experimental smokers, smoking intensity continues to be associated with smoking by some social influence factors—peers, team sports and exposure to tobacco marketing,35
but is also is predominantly driven by addiction processes.43
In this study, sensation seeking was a risk factor for trying smoking and higher smoking intensity, consistent with other research.45
Sensation-seeking level probably captures, in part, biological characteristics that promote experience seeking46
and tolerance of deviance,47
but it may also be associated with higher sensitivity to the addictive influence of nicotine.48
Given its large association with both smoking outcomes in this study, research on using sensation seeking to target high-risk adolescents,49
modifying risk factors that affect sensation seeking deserve greater emphasis. For example, one study suggested that higher exposure to adult-rated movies resulted in higher growth in sensation seeking during adolescence.50
Consistent with other studies that have distinguished between trying smoking and smoking intensity,51
some characteristics were associated with one outcome but not the other. Exposure to smoking in movies was associated with trying smoking but not smoking intensity, consistent with some other reports.35
Minority youth tried smoking at rates similar to White youth, but minority ever smokers had much lower smoking intensity than Whites. This finding is not surprising, given that minority adolescents have lower rates of smoking compared with Whites,52
with larger temporal declines in smoking among Black adolescents54
and lower rates of progression to regular use.55
Studies of trying smoking have been inconsistent, with some confirming lower rates among minorities,56
including this one, did not. Why minority youth that try smoking have lower-smoking intensity than Whites deserves further research, given that the finding holds across studies;52
minority adolescents could be less susceptible to nicotine addiction in its earliest stages or social or family circumstances could reduce the likelihood of progression of experimental smoking during adolescence.
This study was limited in that it relied on cross-sectional data and therefore cannot address temporality. However, it would be unusual to see a weak correlation in a cross-sectional study become a key predictor in a longitudinal one. The national scope of the study could be viewed as a strength but precluded us from directly assessing where tobacco outlets were in each community. Instead, we relied on available commercial data, subject to higher levels of error. Although this limitation could have widened CIs due to random error, we have no reason to believe that the error is larger in some neighbourhoods than others, which would lead to biased estimates. We suggest that, even if the results were statistically significant, the size of the associations were still small for tobacco outlet density and the other community characteristics we measured.
Compared to individual risk factors, tobacco outlet density might be less relevant for minors who are legally constrained in their purchase of tobacco. One previous study of adolescent smoking found no association for tobacco outlet density but a positive association between access—the proportion of stores that illegally sell to minors—and youth smoking.25
This suggests that tobacco outlet density could be more important in determining smoking patterns among adults, who are less constrained in their purchase of tobacco at retail outlets. Although we found no evidence for that in the small number of adults present in this sample, further study in adult samples may be indicated. Our study did not explicitly measure exposure to tobacco storefront advertising in the context of community-level influences and therefore cannot address this issue explicitly—we cannot rule out a storefront advertising influence without more elaborate measurements of access to this particular aspect of tobacco retailing. Tobacco outlet density should be a proxy for exposure to storefront advertising but would not capture individual differences in how adolescents respond to or remember it, which could explain differences between our findings and those of others who assessed recollection of storefront advertising.58
Finally, we studied tobacco density and proximity at home, not in school. McCarthy et al
. looked at the relationship between tobacco retail density near schools and youth tobacco use and found that the effects were limited to trying smoking (not established smoking), and only among high-school students in urban areas.59
However, their work did not include the depth of individual-level variables presented in this analysis. Future studies should consider the role of tobacco outlet density and proximity around schools in the context of individual risk factors for adolescent smoking.
This study adds to the growing body of evidence that public health campaigns to prevent and reduce youth smoking should emphasise individual risk factors for smoking, including supporting participation in team sports, minimising exposure to movie smoking, addressing the social influence of friend smoking and addressing experience seeking among high sensation-seekers.