Risk factors for breast cancer development by tumor characteristics among women with benign breast disease

Breast Cancer Research

Table 2 Multivariable associations between select patient characteristics and histologic features with breast cancer risk by ER status (N = 969)

Variable	Controls (N = 514)		Cases, ER+ (N = 391)		ER+ vs. controls	Cases, ER− (N = 64)		ER− vs. controls	P-het^†
Variable	N^a	%^a	N^a	%^a	OR (95% CI)*	N^a	%^a	OR (95% CI)*	P-het^†
Age at first full-term birth/years
Nulliparous/≥ 30	108	20.9	88	27.6	1.00 (ref)	13	20.3	1.00 (ref)	0.24
< 30	406	79.1	231	72.4	0.69 (0.49, 0.98)	51	79.7	1.08 (0.51, 2.30)
P-value					0.038			0.84
Family history of breast cancer
No	434	84.4	257	80.7	1.00 (ref)	50	77.5	1.00 (ref)	0.56
Yes	80	15.6	62	19.3	1.30 (0.89, 1.88)	14	22.5	1.60 (0.77, 3.33)
P-value					0.17			0.20
History of bilateral oophorectomy
No	429	83.4	346	88.6	1.00 (ref)	55	85.9	1.00 (ref)	0.42
Yes	85	16.6	45	11.4	0.59 (0.38, 0.90)	9	14.1	0.82 (0.37, 1.80)
P-value					0.015			0.62
BBD histology
Normal/non-proliferative	384	74.7	243	62.2	1.00 (ref)	43	67.2	1.00 (ref)	0.45
Proliferative without atypia	124	24.1	127	32.5	1.70 (1.25, 2.30)	20	31.3	1.49 (0.84, 2.67)
Proliferative with atypia	6	1.2	21	5.4	5.48 (2.14, 14.01)	1	1.6	–
P-trend					< 0.0001			–
Subjective impression of involution
None/mildly involuted (0–24%)	235	45.7	187	47.8	1.00 (ref)	27	42.2	1.00 (ref)	0.85
Partially involuted (25–74%)	75	14.6	78	20.0	1.38 (0.93, 2.04)	12	18.8	1.48 (0.70, 3.13)
Completely involuted (≥ 75%)	135	26.3	84	21.5	0.87 (0.61, 1.24)	15	23.4	1.07 (0.53, 2.13)
No TDLU observed	69	13.4	42	10.7	0.69 (0.43, 1.10)	10	15.6	1.28 (0.57, 2.91)
P-trend^b					0.68			0.90
Columnar cell lesions^c
None	450	87.9	328	84.1	1.00 (ref)	53	82.8	1.00 (ref)	0.94
Present with/without atypia	62	12.1	62	15.9	1.54 (1.03, 2.29)	11	17.2	1.50 (0.73, 3.07)
P-value					0.034			0.27

Fifty-nine cases who had missing ER status were excluded from modeling analyses. BBD benign breast disease, CI confidence interval, ER estrogen receptor, OR odds ratio. ^aAveraged frequencies and percentages. ^bWomen with zero-TDLU observed were not included in trend tests or heterogeneity tests. ^cTwo controls and two cases were missing for columnar cell lesions. *OR and 95% CI estimates were calculated using polytomous logistic regression models adjusted for categorized BBD diagnosis calendar year as a trend, continuous age at BBD and follow-up period from BBD diagnosis to breast cancer diagnosis, family history of breast cancer in 1st-degree relatives, history of bilateral oophorectomy, BBD histology, and parity. ^†P-heterogeneity was calculated from case-case analyses. Involution and columnar cell lesion associations were adjusted for all factors above the line indicated in OR*

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