Table 3.

Mutually adjusted odds ratios and 95% confidence intervals of reproductive and hormonal factors in relation to lung cancer in the hospital-based lung cancer case-control study.

	Cases	Controls	Mutually adjusted a
	N	N	OR (95% CI)
Age at menarche (years)
<14	46	50	1.04 (0.57, 1.87)
14	58	62	0.84 (0.48, 1.46)
≥15	134	101	1 (referent)
Age at menopause (years)
Premenopausal	25	71	0.71 (0.29, 1.70)
<45	61	39	1.74 (0.90, 3.38)
45–49	98	55	1.72 (0.94, 3.15)
≥50	71	52	1 (referent)
Number of pregnancies (gravidity)
≤ 2	40	43	0.82 (0.40, 1.68)
3–5	116	121	1 (referent)
>5	111	62	1.15 (0.69, 1.91)
Age at first live-birth (years)
Never Pregnant	15	10	2.39 (0.55, 10.36)
<18	50	47	0.75 (0.40, 1.41)
18–20	98	80	1 (referent)
≥21	79	69	0.77 (0.45, 1.31)
Birth control use
Ever	29	39	0.82 (0.42, 1.59)
Never	227	177	1 (referent)

OR, odds ratio; CI, confidence interval.

^aEstimates were simultaneously adjusted for all reproductive and hormonal exposures listed above, in addition to adjustment for age and cumulative active smoking years; one subject with missing cumulative active smoking history was excluded.

Unknown categories were retained in the model but not presented here.