Table 4.

Estimated hazard functions^a (95% confidence intervals^b) in PATH young adults of the age of initiation of smokeless tobacco use outcomes by sex

Age of Initiation (years)	Ever		Past 30-day		Fairly regular
18	0.0	0.0	0.0	0.0	0.0	0.0
19	1.5 (0.1–2.9)	0.2 (0.1–0.3)	1.2 (0.9–1.5)	0.1 (0.04–0.2)	1.2 (0.9–1.5)	0.1 (0.04–0.2)
20	2.8 (2.2–3.4)	0.6 (0.4–0.8)	1.7 (1.3–2.2)	0.3 (0.1–0.5)	1.7 (1.3–2.2)	0.3 (0.1–0.5)
21	4.0 (3.2–4.8)	0.7 (0.4–0.9)	2.6 (2.0–3.2)	0.3 (0.2–0.5)	2.6 (2.0–3.2)	0.3 (0.2–0.5)
22	4.4 (3.5–5.2)	0.9 (0.6–1.2)	2.6 (2.0–3.2)	0.3 (0.2–0.5)	2.6 (2.0–3.2)	0.3 (0.2–0.5)
23	4.4 (3.6–5.2)	0.9 (0.6–1.2)	2.8 (2.2–3.4)	0.4 (0.2–0.6)	2.8 (2.2–3.4)	0.4 (0.2–0.6)
24	5.9 (4.4–7.4)	1.3 (0.9–1.7)	4.2 (2.7–5.6)	0.8 (0.5–1.1)	4.2 (2.7–5.6)	0.8 (0.5–1.1)
25	6.9 (5.2–8.7)	1.4 (1.1–1.8)	4.9 (3.1–6.7)	0.8 (0.5–1.1)	4.9 (3.1–6.7)	0.8 (0.5–1.1)
26	8.1 (6.6–9.5)	1.5 (1.1–2.0)	5.5 (4.3–6.7)	0.9 (0.5–1.3)	5.5 (4.3–6.7)	0.9 (0.5–1.3)
27	9.0 (6.8–11.2)	1.7 (1.2–2.3)	5.6 (4.4–6.9)	1.1 (0.5–1.7)	5.6 (4.4–6.9)	1.1 (0.5–1.7)

^aHazards are reported as cumulative percentages (i.e. cumulative incidence).

^bTurnbull 95% confidence interval.