A Nation-Wide multicenter 10-year (1999-2008) retrospective clinical epidemiological study of female breast cancer in china

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	0.285^b
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	0.665^b
> 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	0.200^c
≥ 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	0.030^b
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	0.082^b
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	0.861^b
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	< 0.001^c
Now	11	0.3	10	0.4	1	0.1
Unknown	3332	79.1	1890	74.0	766	85.0

ISSN: 1471-2407