Table 3.

Risk of ET by cigarette pack-year tertiles

	Unadjusted Model			Adjusted model*
	RR	95% CI	p value	RR	95% CI	p value
Lowest pack-year tertile (<19.2)	1.02	0.53–1.96	0.95	0.88	0.41–1.89	0.74
Middle pack-year tertile (19.2–49.0)	1.003	0.52–1.93	0.99	0.82	0.36–1.88	0.65
Highest pack-year tertile (>49.0)	0.37	0.14–1.03	0.057	0.29	0.09–0.90	0.03
Test for trend	p = 0.13			p = 0.048

^*The reference category was non-smokers.

^*Adjusted for age in years, gender, educational level, drink-years, and depressive symptoms.