Table 4.

Weighted and Unweighted Breast Cancer Incidence Model by Tumor Size Among Women in the Nurses’ Health Study, 1988–2000

Variable	Tumor Size, ≤2 cm				Tumor Size, >2 cm
	Unweighted		Weighted		Unweighted		Weighted
	β (SE)	P Value	β (SE)	P Value	β (SE)	P Value	β (SE)	P Value
Constant	−10.569 (0.446)	<0.001	−10.387 (0.453)	<0.001	−9.379 (0.694)	<0.001	−9.127 (0.695)	<0.001
Premenopause duration, yearsa	0.099 (0.011)	<0.001	0.096 (0.012)	<0.001	0.058 (0.018)	0.002	0.058 (0.018)	0.0016
Menopause duration, years
Natural	0.040 (0.007)	<0.001	0.039 (0.007)	<0.001	0.010 (0.011)	0.35	0.012 (0.011)	0.30
Bilateral oophorectomy	0.031 (0.009)	<0.001	0.032 (0.009)	<0.001	0.0029 (0.015)	0.84	0.0063 (0.0147)	0.67
Pregnancy history
Age at first birth − age at menarche	0.0081 (0.0061)	0.18	0.0085 (0.0064)	0.19	0.0061 (0.0097)	0.53	−0.0018 (0.0097)	0.85
Birth index	−0.0023 (0.0008)	0.008	−0.0025 (0.0009)	0.005	−0.0047 (0.0014)	0.001	−0.0064 (0.0015)	<0.001
Benign breast disease
BBD, yes versus no	1.102 (0.742)	0.14	0.789 (0.780)	0.31	−0.299 (1.146)	0.79	−1.114 (1.185)	0.35
BBD × age at menarche	0.042 (0.03)	0.16	0.048 (0.032)	0.14	0.055 (0.047)	0.24	0.087 (0.049)	0.076
BBD × premenopause duration	−0.028 (0.014)	0.051	−0.024 (0.015)	0.11	0.0004 (0.023)	0.98	0.0090 (0.0231)	0.70
BBD × menopause duration	−0.021 (0.008)	0.008	−0.020 (0.008)	0.013	0.0069 (0.012)	0.58	0.0091 (0.0126)	0.47
Hormone therapy
Oral estrogen duration	0.030 (0.01)	0.002	0.029 (0.010)	0.004	0.026 (0.017)	0.12	0.019 (0.017)	0.27
Oral estrogen and progesterone duration	0.065 (0.014)	<0.001	0.065 (0.015)	<0.001	0.051 (0.025)	0.039	0.051 (0.026)	0.049
Other hormone types’ duration	0.022 (0.014)	0.11	0.016 (0.014)	0.25	0.065 (0.019)	<0.001	0.049 (0.021)	0.017
Current use	0.177 (0.088)	0.043	−0.011 (0.094)	0.90	−0.134 (0.144)	0.35	−0.271 (0.152)	0.074
Past use	0.017 (0.089)	0.85	−0.026 (0.092)	0.78	−0.302 (0.153)	0.049	−0.377 (0.157)	0.016
Body mass index, kg/m2
Average BMI during premenopause × premenopause durationb	−0.0012 (0.0003)	<0.001	−0.0012 (0.0003)	<0.001	−0.0002 (0.0004)	0.63	−0.00019 (0.00047)	0.69
Average BMI during postmenopause × menopause durationc	0.0035 (0.0007)	<0.001	0.0037 (0.0007)	<0.001	0.0034 (0.0012)	0.004	0.0032 (0.0012)	0.006
Height, inches
Height × premenopause durationb	0.0010 (0.0004)	0.005	0.0011 (0.0004)	0.006	0.0011 (0.0006)	0.073	0.0011 (0.0006)	0.094
Height × menopause durationc	−0.0008 (0.0016)	0.61	−0.00075 (0.00163)	0.65	−0.0010 (0.0026)	0.71	−0.0013 (0.0027)	0.63
Alcohol use
Cumulative ounces before menopause	0.0004 (0.0001)	<0.001	0.00041 (0.00011)	<0.001	0.0003 (0.0002)	0.076	0.00042 (0.00017)	0.013
Cumulative ounces after menopause
With hormone therapy	−0.0009 (0.0005)	0.066	−0.00066 (0.00049)	0.17	−0.0005 (0.0008)	0.53	−0.00051 (0.00079)	0.52
Without hormone therapy	−0.0003 (0.0004)	0.46	−0.00019 (0.00037)	0.60	−0.0003 (0.0006)	0.65	−0.00023 (0.00061)	0.71
Family history of breast cancer	0.470 (0.072)	<0.001	0.416 (0.077)	<0.001	0.217 (0.129)	0.092	0.138 (0.136)	0.31

Abbreviations: BBD, benign breast disease; BMI, body mass index; SE, standard error.

^aPremenopause duration = minimum(age, age at menopause) − age at menarche.

^bIncluding time postmenopausal while taking postmenopausal hormones.

^cTime postmenopausal while not taking postmenopausal hormones.