Use of E-cigarettes, Cigarettes, or Dual Product Use at Baseline and Odds of Past-30-Day Use at Follow-up

Baseline Product UsePast-30-d Use at Follow-up
Exclusively E-cigarettes Versus None, OR (95% CI)Exclusively Cigarettes Versus None, OR (95% CI)Dual Use Versus None, OR (95% CI)
Past-30-d usea,b,c
 Neither productReferenceReferenceReference
 Exclusively e-cigarettes7.28 (4.86–10.9)d3.84 (1.80–8.19)d8.86 (5.08–15.4)d
 Exclusively cigarettes4.03 (1.30–12.6)d29.5 (12.3–70.8)e28.8 (12.6–66.1)e
 Dual product11.3 (5.51–23.2)d44.3 (20.4–96.1)e105 (56.6–194)f
  • Superscript letters denote a test of independence of effect estimates by row; estimates sharing letters are not statistically significantly different from one another (P < .05).

  • a Stability estimates of remaining in a use pattern (versus nonuse) on the diagonal.

  • b Adjusted for gender, race and/or ethnicity, grade, and study with a random effect for school.

  • c Restricted to the CHS and YASS.