Table 4.

Duration of current use relative to never use of menopausal hormone therapy and risk of breast tumor characteristics

	<5 years current MHT		≥ 5 years current MHT
	Crude	Adjusteda	Crude	Adjusteda
Tumor size
≤ 10 mm	Reference	Reference	Reference	Reference
11 to 20 mm	1.1 (0.8 to 1.6)	1.1 (0.8 to 1.7)	1.0 (0.7 to 1.3)	1.0 (0.8 to 1.4)
21 to 50 mm	1.4 (0.9 to 2.0)	1.2 (0.8 to 1.9)	0.6 (0.4 to 0.9)	0.6 (0.4 to 0.9)
>50 mm	1.0 (0.4 to 2.6)	0.8 (0.3 to 2.3)	0.6 (0.2 to 1.6)	0.7 (0.2 to 1.7)
Lymph node involvement
0 lymph nodes	Reference	Reference	Reference	Reference
1 to 3 lymph nodes	1.0 (0.7 to 1.4)	0.8 (0.5 to 1.2)	1.2 (0.9 to 1.7)	1.1 (0.8 to 1.6)
>3 lymph nodes	0.9 (0.6 to 1.5)	0.8 (0.5 to 1.4)	0.7 (0.4 to 1.1)	0.6 (0.4 to 1.1)
Grade
1	Reference	Reference	Reference	Reference
2	0.9 (0.5 to 1.6)	1.3 (0.7 to 2.4)	0.4 (0.3 to 0.7)	0.5 (0.3 to 0.7)
3	1.3 (0.8 to 2.3)	1.5 (0.8 to 2.7)	0.3 (0.2 to 0.5)	0.3 (0.2 to 0.5)
Histology
Ductal	Reference	Reference	Reference	Reference
Lobular	1.4 (1.0 to 2.2)	1.5 (1.0 to 2.5)	1.9 (1.3 to 2.8)	2.0 (1.4 to 2.9)
Other	0.8 (0.5 to 1.2)	0.9 (0.5 to 1.4)	2.0 (1.4 to 2.7)	2.0 (1.4 to 2.8)
Estrogen receptor (ER), progesterone receptor (PR) status
ER-PR-	Reference	Reference	Reference	Reference
ER+PR-	0.9 (0.5 to 1.5)	1.2 (0.6 to 2.4)	0.9 (0.4 to 1.8)	1.0 (0.5 to 2.1)
ER-PR+	1.9 (0.9 to 4.0)	1.5 (0.6 to 3.7)	2.6 (1.1 to 6.0)	2.8 (1.2 to 6.7)
ER+PR+	0.9 (0.6 to 1.4)	1.1 (0.7 to 1.8)	2.0 (1.2 to 3.3)	2.1 (1.3 to 3.6)

Data presented as the odds ratio (95% confidence interval) relative to never users of menopausal hormone therapy (MHT). For each tumor characteristic, the first row is the control group, and the other groups are the case groups. Never use of MHT is the reference group, and <5 years or > 5 years of current MHT are the exposure groups. ^aAdjusted for recent mammography (yes/no) and age at diagnosis (5-year categories).