Table 2.

Relationship between VBD percentage or FGV and the risk factors for breast cancer.

	VBD percentage (%)						FGV (cm3)
	Q1 (<10) N = 379	Q2 (10–14.0) N = 379	Q3 (14.1–18.5) N = 381	Q4 (18.6–23.6) N = 379	Q5 (≥23.7) N = 383	Ptrend	Q1 (<57) N = 360	Q2 (57–78) N = 393	Q3 (79–103) N = 376	Q4 (104–135) N = 386	Q5 (≥136) N = 386	Ptrend
Age (yr, mean)	54.5	50.1	46.0	45.1	43.5	0.000	51.9	49.2	47.1	45.6	45.7	.000
BMI (kg/m2,mean)	24.78	24.49	23.50	23.08	22.42	0.000	23.40	23.56	23.75	23.72	23.81	.042
Menarche (yr, mean)	14.78	14.28	14.43	14.39	14.29	0.002	14.71	14.45	14.35	14.39	14.29	.002
Age at first birth (yr, mean)	24.58	24.96	24.83	25.15	25.30	0.003	24.70	24.66	25.14	24.98	25.34	.004
Number of births (%)
0	15	20.0	20.0	15	30	0.000	11.7	11.7	23.3	31.7	21.7	.000
1	14.2	20.3	21.2	20.6	23.8		16.3	21.3	19.5	20.3	22.7
2	21.2	19.0	19.6	21.1	19.1		19.9	19.7	20.8	19.9	19.7
≥3	37.8	21.2	15.4	15.4	8.1		27.4	23.2	17.4	18.9	13.1
Breastfeeding (mo, %)
0	22.0	16.7	16.1	21.4	23.8	0.000	17.9	18.5	17.9	20.2	25.6	.015
1–12	12.9	19.5	22.0	22.2	23.4		15.6	21.8	21.7	20.2	20.7
>12	23.6	20.9	19.6	18.6	17.3		21.3	20.8	18.9	19.9	19.2
Menstrual status (%)
Premenopausal	8.2	15.1	23.7	25.6	27.4	0.000	12.5	18.8	20.6	23.8	24.3	.000
Postmenopausal	37.9	27.3	14.5	11.2	9.2		28.7	23.5	18.5	15.0	14.2
Oral contraceptives (%)	21.6	18.9	20.2	17.9	21.4	0.756	17.0	23.4	20.9	20.2	18.4	.633
Family history (%)	24.0	16.0	23.0	24.0	13.0	0.294	25.0	15.0	19.0	19.0	22.0	.75