Table 3.

Reproductive characteristics of breast cancer cases

Variables by level	Total distribution (N = 4211)		Clinical Stage I&II (N = 2554)		Clinical Stage III&IV (N = 901)		ES vs. LS P-value
	n	%	n	%	n	%
Menopausal Status (4211, 2554, 901)
Pre-menopausal	2649	62.9	1585	62.1	541	60.0	0.285b
Post-menopausal	1562	37.1	969	37.9	360	40.0
Age at Menopause (Years) (1562, 969, 360) **
≤ 50	1017	65.1	631	65.1	239	66.4	0.665b
> 50	545	34.9	338	34.9	121	33.6
Age at Menarche (Years) (150, 80, 50)
7~11	3	2.0	0	0.0	2	4.0
12~13	37	24.7	22	27.5	11	22.0	0.200c
≥ 14	110	73.3	58	72.5	37	74.0
Age at First Delivery (Years) (2021, 1372, 357 )
< 20	33	1.6	15	1.1	11	3.1
20~24	917	45.4	638	46.5	153	42.9	0.030b
25~29	940	46.5	632	46.1	166	46.5
≥ 30	131	6.5	87	6.3	27	7.6
Number of Live Births (3947, 2428, 807)
0	99	2.5	44	1.8	17	2.1
1	1889	47.9	1177	48.5	348	43.1
2	1228	31.1	767	31.6	269	33.3	0.082b
3	452	11.5	271	11.2	110	13.6
≥ 4	279	7.1	169	7.0	63	7.8
Breast Feeding History (2671, 1754, 492)
Yes	2414	90.4	1591	90.7	445	90.5	0.861b
No	257	9.6	163	9.3	47	9.5
O.C Consumption History (4211, 2554, 901)
Never	543	12.9	376	14.7	98	10.9
Used	325	7.7	278	10.9	36	4.0	< 0.001c
Now	11	0.3	10	0.4	1	0.1
Unknown	3332	79.1	1890	74.0	766	85.0

^a Student's t-test

^b Chi-square test

^c Fisher's exact test

** Median age of menopause has been used to create the two age-categories.