Table 4.

Population-Level Proportion of Cigarette Use Attributable to Prior Use of Non-cigarette Tobacco Products, Population Assessment of Tobacco and Health Study^a

	Cigarette ever use		Cigarette past-30-day use
Prior use	PAF,b %	Attributable users in 2017, No.c,d,e	PAF,b %	Attributable users in 2017, No.c,d,e
Overall
Ever e-cigarette use	17.9	170 000	22.6	108 000
Ever cigar use	4.6	44 000	6.8	33 000
Ever other product use	6.9	65 000	11.8	57 000
NH white
Ever e-cigarette use	20.6	118 000	26.0	77 000
Ever cigar use	3.9	22 000	3.2	9000
Ever other product use	7.2	41 000	11.2	33 000
NH black
Ever e-cigarette use	3.5	3000	2.3	1000
Ever cigar use	9.1	7000	12.2	5000
Ever other product use	1.0	1000	3.1	1000
Hispanic
Ever e-cigarette use	21.6	50 000	22.1	26 000
Ever cigar use	3.9	9000	9.0	10 000
Ever other product use	6.1	14 000	13.3	15 000

e-cigarette, electronic cigarette; PAF, Population Attributable Fraction; CI, confidence interval.

^aResults for non-Hispanic Other youth are not included due to low sample size and lack of precision.

^bPAF = (observed number of cases - expected number of cases under no exposure)/observed number of cases, where both components were derived from marginal standardization using risk estimates from the prior regression models.

^cNew cigarette use was measured after 1-year follow-up at Wave 4. Data were collected for Wave 4 between December 2016 and January 2018. Results were rounded to the nearest 1000.

^dAttributable Users = (PAF)*(Total New Users between Wave 3 and Wave 4).

^eTotal new ever cigarette users between Wave 3 and Wave 4 was 948 022 for the overall sample, 573 940 for non-Hispanic white, 77 354 for non-Hispanic black, and 232 437 for Hispanic youth. Total new past-30-days between Wave 3 and Wave 4 was 479 960 for the overall sample, 292 042 for non-Hispanic white, 40 203 for non-Hispanic black, and 115 767 for Hispanic youth.