FIGURE 1—

Directed acyclic graph to test the hypothesized relationship of cigarette excise tax and periodontitis operating via cigarette pack sales and secondhand smoke exposure pathway.

Note. CI = confidence interval; OR = odds ratio. All ORs adjusted for age in years, gender, and National Health and Nutrition Examination Survey cycle (i.e., 1999–2000; 2001–2002; 2003–2004).

^aORs are for each additional $0.10 in tax excise (expressed as constant-dollar value in 1982–1984).

^bData available as a supplement to the online version of this article at http://www.ajph.org for the relationship between cigarette excise tax and per capita sales.

^cORs are for each additional pack/person/month cigarette sales.

^dSecondhand smoke exposure dichotomized as < 0.05 ng/mL vs ≥ 0.05 ng/mL.

^eCenters for Disease Control and Prevention/American Academy of Periodontology case classification for moderate or severe periodontitis defined as ≥ 2 interproximal sites with clinical attachment level ≥ 4 mm, not on the same tooth, or ≥ 2 interproximal sites with probing depth ≥ 5 mm, not on the same tooth.