Table 2

Correlates of initiating P30D use among never users (youth 12–17 years) at baseline

P30D use at follow-up
Any tobaccoCigarettesENDSCigarsHookahSmokeless
Correlates at baseline%95% CIaOR1 95% CI%95% CIaOR1 95% CI%95% CIaOR1 95% CI%95% CIaOR1 95% CI%95% CIaOR1 95% CI%95% CIaOR1 95% CI
Overall4.4(4.0-4.7)N/AN/A2.0(1.8-2.2)N/AN/A3.1(2.8-3.4)N/AN/A1.7(1.5-1.9)N/AN/A1.4(1.3-1.6)N/AN/A0.8(0.7-0.9)N/AN/A
Demographic characteristics
 Age group
  12-142.3(2.0-2.7)----1.0(0.7-1.3)----1.6(1.3-1.9)----0.4(0.3-0.6)----0.5(0.4-0.6)----0.4(0.3-0.5)----
  15-177.1(6.4-7.8)3.2(2.6-3.8)***3.2(2.9-3.6)2.4(1.8-3.3)***4.9(4.3-5.5)2.4(1.9-3.0)***3.2(2.8-3.5)5.7(3.9-8.3)***2.5(2.2-2.9)4.1(2.9-5.9)***1.2(1.0-1.5)2.1(1.3-3.3)**
 Sex
  Female4.3(3.7-4.9)----2.0(1.7-2.3)----2.8(2.4-3.4)----1.2(1.0-1.4)----1.5(1.2-1.8)----0.3(0.2-0.4)----
  Male4.5(4.0-5.0)1.0(0.9-1.3)2.0(1.7-2.3)0.8(0.6-1.0)3.3(2.9-3.8)1.2(1.0-1.5)2.3(2.0-2.6)2.3(1.7-3.0)***1.4(1.2-1.6)0.8(0.6-1.0)1.3(1.0-1.5)4.6(2.7-7.9)***
 Race/ethnicity
  Non-Hispanic White4.9(4.5-5.5)----2.4(2.1-2.7)----3.8(3.3-4.3)----1.8(1.6-2.1)----1.3(1.1-1.6)----1.1(0.9-1.4)----
  Non-Hispanic Black3.4(2.6-4.5)0.7(0.5-0.9)**1.4(1.0-2.0)0.6(0.4-0.9)*1.8(1.3-2.6)0.5(0.3-0.6)***2.0(1.5-2.8)1.3(0.9-1.9)1.4(1.1-2.0)1.2(0.8-1.7)####
  Non-Hispanic Other (includes two or more races)2.9(2.1-4.0)0.6(0.4-0.8)**1.5(0.9-2.3)0.7(0.4-1.1)2.4(1.7-3.2)0.6(0.4-0.8)**1.3(0.9-2.0)0.9(0.5-1.4)1.5(1.0-2.2)1.2(0.8-2.0)####
  Hispanic4.4(3.8-5.1)0.9(0.8-1.1)1.8(1.5-2.2)0.8(0.6-1.0)*2.6(2.2-3.1)0.7(0.5-0.8)**1.4(1.2-1.8)0.8(0.7-1.1)1.7(1.4-2.2)1.5(1.1-2.0)*0.5(0.3-0.8)0.4(0.2-0.8)**
 Sexual orientation (ages 14+)
  Straight/Heterosexual5.9(5.3-6.4)----2.5(2.2-2.8)----3.9(3.4-4.4)----2.5(2.2-2.8)----2.0(1.7-2.3)----1.0(0.8-1.2)----
  Other (includes gay, lesbian, bisexual, other)9.1(7.1-11.7)1.6(1.2-2.2)**5.1(3.5-7.2)1.9(1.3-2.9)**8.0(6.1-10.4)1.9(1.3-2.6)***3.3(2.3-4.7)1.4(0.9-2.2)3.1(2.1-4.7)1.2(0.7-1.9)0.9(0.5-1.7)0.9(0.4-1.7)
Tobacco use correlates
 Use of cigarettes
  Never useN/AN/AN/AN/AN/AN/AN/AN/A2.5(2.2-2.8)----1.2(1.1-1.4)----1.1(0.9-1.3)----0.5(0.4-0.6)----
  Ever useN/AN/AN/AN/AN/AN/AN/AN/A13.6(11.0-16.7)2.9(2.1-4.0)***7.5(6.3-9.0)2.7(1.9-3.7)***4.8(3.7-6.1)1.1(0.6-2.0)3.3(2.6-4.2)3.4(2.0-5.8)***
 Use of ENDS
  Never useN/AN/AN/AN/A1.5(1.3-1.7)----N/AN/AN/AN/A1.2(1.0-1.4)----1.0(0.9-1.2)----0.5(0.4-0.7)----
  Ever useN/AN/AN/AN/A8.5(6.9-10.3)3.4(2.4-4.7)***N/AN/AN/AN/A6.4(5.3-7.7)2.4(1.7-3.5)***4.9(3.9-6.1)3.1(2.0-4.7)***2.7(2.1-3.4)2.1(1.1-3.9)*
 Use of cigars
  Never useN/AN/AN/AN/A1.8(1.6-2.0)----2.8(2.5-3.1)----N/AN/AN/AN/A1.2(1.0-1.4)----0.6(0.5-0.8)----
  Ever useN/AN/AN/AN/A11.6(7.8-16.9)2(1.1-3.7)*18.3(14.5-22.8)2.5(1.8-3.5)***N/AN/AN/AN/A7.5(5.6-10.1)2.3(1.4-3.7)**3.7(2.7-5.1)1.3(0.7-2.4)
 Use of hookah
  Never useN/AN/AN/AN/A1.7(1.5-2.0)----2.7(2.4-3.0)----1.5(1.3-1.6)----N/AN/AN/AN/A0.7(0.6-0.8)----
  Ever useN/AN/AN/AN/A9.9(7.7-12.5)2.2(1.5-3.2)***16.3(13.0-20.3)2.6(1.9-3.7)***7.0(5.5-9.0)1.6(1.2-2.3)**N/AN/AN/AN/A2.4(1.7-3.5)1.1(0.6-2.0)
 Use of smokeless
  Never useN/AN/AN/AN/A1.8(1.6-2.1)----2.9(2.6-3.2)----1.5(1.4-1.7)----1.3(1.2-1.5)----N/AN/AN/AN/A
  Ever useN/AN/AN/AN/A11.3(8.0-15.7)2.7(1.5-4.7)***12.8(8.8-18.3)1.6(1.0-2.6)8.2(6.1-11.0)1.6(1.1-2.3)*4.8(3.2-7.1)1.2(0.7-2.1)N/AN/AN/AN/A
  • The percentages and ORs in the table are based on weighted data.

  • Denominator N (unweighted number of observations) for aOR in ‘any tobacco’=15 922 (without sexual orientation), 9494 (with sexual orientation).

  • Denominator N (unweighted number of observations) for aOR in ‘cigarettes’=18 184 (without sexual orientation), 11 338 (with sexual orientation).

  • Denominator N (unweighted number of observations) for aOR in ‘ENDS’=17 782 (without sexual orientation), 11 000 (with sexual orientation).

  • Denominator N (unweighted number of observations) for aOR in ‘cigars’=19 257 (without sexual orientation), 12 216 (with sexual orientation).

  • Denominator N (unweighted number of observations) for aOR in ‘hookah’=19 338 (without sexual orientation), 12 276 (with sexual orientation).

  • Denominator N (unweighted number of observations) for aOR in ‘smokeless’=19 662 (without sexual orientation), 12 713 (with sexual orientation).

  • Tobacco product types were categorised into five groups: cigarettes, ENDS (e-cigarettes at Wave 1, and e-cigarettes, e-cigars, e-pipes and e-hookah at Waves 2 and 3), cigars (ie, traditional cigars, cigarillos, filtered cigars), hookah and smokeless tobacco (ie, loose snus, moist snuff, dip, spit, chewing tobacco and snus pouches).

  • For each of the five tobacco products, and for any tobacco product, use is defined with respect to the given tobacco product/any tobacco product.

  • Never use is defined as never having used the product, even one or two times.

  • P30D use is defined as use in the past 30 days.

  • The outcome ‘initiating P30D’ is defined as P30D use at follow-up (vs no P30D use at follow-up) among never users at baseline.

  • Since never use at baseline is defined with respect to each tobacco product, never/ever use of ‘other’ tobacco products at baseline are considered as correlates of initiating P30D use of the given tobacco product at follow-up.

  • GEE logistic regression analyses were used to assess correlates of initiating P30D use at follow-up among never users at baseline over a 1-year period of time (ie, Wave 1–Wave 2 and Wave 2–Wave 3), including up to two change data points per individual and statistically controlling for the correlation among observations from the same individuals.

  • All correlates reflect baseline measurement for each wave pair (eg, when evaluating change between Wave 1 and Wave 2, the age correlate reflects a person’s age at Wave 1, and when evaluating change between Wave 2 and Wave 3, the age correlate reflects a person’s age at Wave 2).

  • Data consist of those who are youth at all three waves, youth who age into the adult cohort at wave 3, shadow youth who age into the youth cohort at Wave 2 and Wave 1–Wave 2 data only from youth who age into the adult cohort at Wave 2 (their Wave 2–Wave 3 data are included in adult tables).

  • 1Analyses adjusted for age group, sex, race/ethnicity, each tobacco use correlate and wave. Sexual orientation (asked only of those 14 years and older) was run separately and not included as a covariate in the other aORs.

  • #Estimates with relative SE >30 or denominator <50 are suppressed.

  • *P<0.05. **p <0.01, ***p<0.001.

  • aOR, adjusted OR; ENDS, electronic nicotine delivery system; GEE, generalised estimating equation; N/A, not applicable; P30D, past 30 day.