Analyses were conducted with the use of Stata 12 software.32 Prevalence estimates were weighted to represent the U.S. adult and youth populations. Variances were estimated with the method of balanced, repeated replications,33 with Fay’s adjustment set to 0.3 to increase the stability of estimates.34 The logit-transformation method was used to calculate confidence intervals. The tables show 95% confidence intervals for point estimates.
The prevalences of product awareness and use of each product type, use of any cigar, use of smokeless tobacco including snus pouches, and use of any tobacco were computed according to the use categories shown in Table S1 in the Supplementary Appendix as they pertained to adults and youths, stratified according to age group (12 to 14 years, 15 to 17 years, 18 to 24 years, or ≥25 years). Among adults, the prevalence of current regular use (cigarettes) or current use (other tobacco products) was also stratified according to sex, age, race or ethnic group, sexual orientation, educational attainment, total annual household income, and U.S. Census region. Among youths, the prevalences of ever use and use in the previous 30 days were also stratified according to sex, age, race or ethnic group, sexual orientation (asked of those ≥14 years of age), educational level, and U.S. Census region.
The prevalences of overall and product-specific single-product use and multiple-product use were determined in the entire adult study population, in the entire youth study population, among adult tobacco users, and among youth tobacco users. Among adult multiple-product users and separately among youth multiple-product users, all combinations of tobacco products used were determined, and each combination that accounted for at least 1% of multiple-product users is presented.