Table 4.

Multivariable odds ratios and 95% confidence intervals of the relationship between reproductive and hormonal and lung cancer by smoking status.

	<15 Cumulative active smoking years			≥15 Cumulative active smoking years
	Cases	Controls	OR (95% CI)a	Cases	Controls	OR (95% CI)a
	n	n		n	n
Menstrual duration b (years)	18	81	0.95 (0.84, 1.07)	194	61	0.92 (0.87, 0.98)
Still menstruating
Yes	17	60	0.30 (0.10, 0.92)	8	11	0.29 (0.09, 0.88)
No	17	61	1 (referent)	179	53	1 (referent)
Age at menarche (years)
<14	11	32	1.68 (0.65, 4.30)	35	18	0.71 (0.35, 1.44)
14	10	45	1.01 (0.39, 2.61)	48	17	0.89 (0.44, 1.78)
≥15	13	64	1 (referent)	120	37	1 (referent)
p-trenda			0.32			0.37
Age at menopauseb (years)
<45	6	25	2.46 (0.49, 12.24)	55	14	2.27 (1.02, 5.04)
45–49	10	33	3.33 (0.76, 14.60)	88	22	1.81 (0.92, 3.57)
≥50	3	25	1 (referent)	67	27	1 (referent)
p-trenda			0.45			0.03
Number of pregnancies (gravidity)
≤ 2	9	27	1.20 (0.46, 3.13)	31	16	0.62 (0.29, 1.32)
3–5	19	85	1 (referent)	96	36	1 (referent)
>5	10	34	1.88 (0.72, 4.92)	101	28	1.10 (0.60, 2.00)
p-trenda			0.48			0.19
Age at first live-birth (years)
Never pregnant	4	5	3.78 (0.81, 17.62)	11	5	0.45 (0.13, 1.51)
<18	9	27	1.90 (0.67, 5.37)	41	20	0.52(0.25, 1.10)
18–20	11	58	1 (referent)	87	22	1 (referent)
≥21	9	42	1.06 (0.39, 2.88)	70	27	0.58 (0.30, 1.14)
p-trenda			0.35			0.99
Birth control use
Ever	9	28	1.07 (0.43, 2.65)	19	11	0.63 (0.26, 1.49)
Never	27	115	1 (referent)	200	62	1 (referent)

OR, odds ratio; CI, confidence interval.

^aEstimates were adjusted for age and cumulative active smoking years, and exposures listed in the above table as applicable; one subject with missing cumulative active smoking history was excluded.

^bPremenopausal women not included.