TABLE 3—

Incident Tobacco Use Between Years 10 and 11: Second Generation of the Prevention and Intervention Research Center Study, Baltimore, Md, 1993–2004

Ever Use	At Risk	Event	Incidence	RR (95% CI)
Total	214	31	0.14
No work in both years (Ref)	111	4	0.04	1.00
No work to work	52	15	0.29	8.00 (2.79, 22.93)
Work to no work	19	2	0.11	2.92 (0.57, 14.85)
Work both periods	32	10	0.31	8.67 (2.91, 15.81)

Note. RR = relative risk; CI = confidence interval. We assessed the incidence of tobacco use between years 10 and 11. Adolescents at risk for incident tobacco use were defined as never reporting tobacco use since the year-6 assessment through year 10. Incidence was then estimated across the entire sample at risk and then separately across 4 work transition categories: did not work in both years 10 and 11, did not work in year 10 but worked in year 11, worked in year 10 but did not work in year 11, and worked in both years. Relative risk estimates were calculated with adolescents not working in both years as the reference group.