Table 2.

Adjusted Odds Ratios (OR) and 95% Confidence Intervals (95%CI) for Lung Cancer by Reproductive and Hormonal Factors ^a

	Cases (n = 407)		Controls (n = 499)		Model 1*			Model 2**
	N	%	N	%	OR	95% CI	p b	OR	95% CI	p b
Age at Menarche
< 13	179	44.0	209	41.9	1			1
13 – 14	157	38.6	215	43.1	0.82	(0.59 – 1.15)		0.82	(0.58 – 1.18)
≥ 15	62	15.2	67	13.4	1.08	(0.67 – 1.73)	0.85	1.10	(0.66 – 1.82)	0.90
Missing	9	2.2	8	1.6
Continuous					0.99	(0.90 – 1.08)	0.77	0.98	(0.89 – 1.09)	0.73
Cycle Duration (Days)
< 27	83	20.4	119	23.9	1			1
27 – 28	234	57.5	292	58.5	1.07	(0.73 – 1.56)		1.25	(0.83 – 1.89)
≥ 29	79	19.4	78	15.6	1.38	(0.85 – 2.24)	0.20	1.53	(0.91 – 2.56)	0.10
Missing	11	2.7	10	2.0
Continuous					1.04	(0.99 – 1.09)	0.14	1.05	(1.00 – 1.10)	0.08
Parity (Number of Livebirths)
0	78	19.2	88	17.6	1			1
1	112	27.5	117	23.5	1.29	(0.80 – 2.06)		1.33	(0.78 – 2.29)
2	148	36.4	205	41.1	1.28	(0.82 – 1.99)		1.33	(0.79 – 2.22)
≥3	69	17.0	89	17.8	1.07	(0.64 – 1.80)	0.74	1.23	(0.67 – 2.24)	0.57
Continuous					1.03	(0.91 – 1.18)	0.63	1.07	(0.92 – 1.24)	0.40
Age at 1st Livebirth
< 22	67	20.4	52	12.7	1			1
22 – 25	103	31.3	122	29.7	0.92	(0.54 – 1.56)		0.95	(0.54 – 1.65)
26 – 30	116	35.3	165	40.2	0.77	(0.46 – 1.29)		0.73	(0.42 – 1.27)
≥ 31	41	12.5	70	17.0	0.57	(0.31 – 1.06)	0.05	0.52	(0.26 – 1.01)	0.03
Missing	2	0.6	2	0.5
Continuous					0.95	(0.92 – 0.99)	0.01	0.95	(0.91 – 0.99)	0.01
Breastfeeding
Never	78	23.7	94	22.9	1			1
Ever	248	75.4	316	76.9	1.00	(0.67 – 1.50)	0.99	0.98	(0.64 – 1.49)	0.92
Missing	3	0.9	1	0.2
Menopause Status
Premenopausal	38	9.3	64	12.8	1			1
Natural Menopausal	285	70.0	336	67.3	2.06	(0.84 – 5.08)	0.12	2.50	(0.97 – 6.45)	0.06
Induced Menopausal	83	20.4	98	19.6	2.58	(1.02 – 6.56)	0.05	2.87	(1.08 – 7.66)	0.04
Missing	1	0.3	1	0.2
Age at Menopause
< 46	95	25.8	78	18.0	1			1
46 – 50	124	33.6	144	33.2	0.65	(0.41 – 1.02)		0.70	(0.43 – 1.14)
≥ 51	90	24.4	168	38.7	0.49	(0.31 – 0.79)	0.003	0.51	(0.31 – 0.84)	0.01
Missing	60	16.3	44	10.1
Continuous					0.96	(0.93 – 0.99)	0.003	0.96	(0.93 – 0.99)	0.01
Ovariectomy
No	363	89.2	442	88.6	1			1
Yes	44	10.8	57	11.4	1.08	(0.67 – 1.74)	0.76	1.03	(0.62 – 1.71)	0.91
Reproductive Duration
< 33	107	26.3	102	20.4	1			1
33 – 36	98	24.1	106	21.2	0.77	(0.48 – 1.24)		0.84	(0.51 – 1.40)
37 – 40	98	24.1	158	31.7	0.67	(0.43 – 1.06)		0.76	(0.47 – 1.25)
≥ 41	41	10.1	84	16.8	0.44	(0.25 – 0.79)	0.01	0.46	(0.25 – 0.85)	0.02
Missing	63	15.5	49	9.8
Continuous					0.96	(0.93 – 0.98)	0.002	0.96	(0.93 – 0.99)	0.01
Menopause Duration
< 10	65	17.6	105	24.2	1			1
10 – 17	77	20.9	103	23.7	1.50	(0.75 – 3.02)		1.42	(0.67 – 3.03)
18 – 24	68	18.4	92	21.2	1.90	(0.84 – 4.29)		1.80	(0.75 – 4.32)
≥ 25	99	26.8	90	20.7	3.74	(1.56 – 8.97)	0.002	3.69	(1.43 – 9.48)	0.003
Missing	60	16.3	44	10.1
Continuous					1.05	(1.02 – 1.08)	0.001	1.06	(1.02 – 1.09)	0.001
HRT c
Never	305	82.7	322	74.2	1			1
Ever	63	17.1	112	25.8	0.63	(0.42 – 0.95)	0.03	0.61	(0.39 – 0.95)	0.03
Missing	1	0.3	0	-
HRT Duration c
Never Users	305	74.9	322	64.5	1			1
< 4	32	7.9	58	11.6	0.58	(0.34 – 0.99)		0.53	(0.29 – 0.94)
≥ 4	29	7.1	51	10.2	0.70	(0.39 – 1.24)	0.07	0.75	(0.40 – 1.37)	0.11
Missing	41	10.1	68	13.6
Continuous					0.97	(0.92 – 1.02)	0.24	0.97	(0.92 – 1.03)	0.33
OC
Never	306	75.2	367	73.6	1			1
Ever	101	24.8	132	26.5	0.67	(0.45 – 1.00)	0.05	0.60	(0.39 – 0.93)	0.02
OC Duration
Never Users	306	75.2	367	73.6	1			1
< 2	41	10.1	61	12.2	0.57	(0.33 – 0.96)		0.49	(0.28 – 0.87)
≥ 2	49	12.0	61	12.2	0.72	(0.43 – 1.22)	0.10	0.71	(0.41 – 1.26)	0.09
Missing	11	2.7	10	2.0
Continuous					0.98	(0.92 – 1.03)	0.39	0.98	(0.93 – 1.04)	0.54
HRT/OC Combined
HRT Never/OC Never	253	62.2	259	51.9	1			1
HRT Ever/OC Never	42	10.3	82	16.4	0.49	(0.30 – 0.80)	0.004	0.45	(0.26 – 0.76)	0.003
HRT Never/OC Ever	52	12.8	63	12.6	0.44	(0.26 – 0.75)	0.002	0.38	(0.21 – 0.67)	0.001
HRT Ever/OC Ever	21	5.2	30	6.0	0.60	(0.29 – 1.26)	0.18	0.59	(0.27 – 1.31)	0.20
Missing	39	9.6	65	13.0

^aPercentages may not add to 100.0 because of rounding.

^bFor ordinal variables, test for trend was performed.

^cIn menopausal women only.

HRT = Hormone Replacement Therapy.

OC = Oral Contraceptives.

^*Model 1: adjusted for area, age at study, smoking (ever/never, pack-years, time since quitting).

^**Model 2: adjusted for area, age at study, smoking (ever/never, pack-years, time since quitting), ETS, education, BMI.