Table 5.

Multivariate logistic regression analysis of premenopausal breast cancer‐related risk factors

Factors	B	Sb	χ 2	P value	OR (95% CI)
Ethnicity
Hana
Other	0.87	0.091	91.048	<0.001	2.388 (1.997–2.855)
Age at menarche
≤10a
11–12	−1.038	0.413	6.33	0.012	0.354 (0.158–0.795)
13–14	−1.013	0.141	51.852	<0.001	0.363 (0.276–0.479)
15–16	−0.71	0.133	28.356	<0.001	0.492 (0.378–0.638)
17–18	−0.6	0.135	19.673	<0.001	0.549 (0.421–0.716)
≥19	−0.295	0.143	4.243	0.039	0.745 (0.563–0.986)
Marital status
Marrieda
Never married	−0.88	0.138	40.648	<0.001	0.415 (0.317–0.544)
Widowed/ divorced	−1.832	0.256	51.151	<0.001	0.16 (0.097–0.264)
Number of pregnancies
0a
1	0.49	0.095	26.637	<0.001	1.632 (1.355–1.965)
2	0.668	0.081	67.892	<0.001	1.95 (1.664–2.286)
3	0.359	0.078	21.342	<0.001	1.432 (1.229–1.667)
Number of births
0a
1	−2.895	0.214	183.38	<0.001	0.055 (0.036–0.084)
2	−3.071	0.205	225.333	<0.001	0.046 (0.031–0.069)
3	−2.496	0.204	149.986	<0.001	0.082 (0.055–0.123)
4	−1.48	0.208	50.452	<0.001	0.228 (0.151–0.343)
≥5	−0.835	0.228	13.392	<0.001	0.434 (0.278–0.679)

^aReferent.