Table 2.

Association of sclerosing adenosis and other risk factors with risk of breast cancer

Characteristic	SA absent				SA present				p value
	No. women	Observed events	Expected events	SIR (95 % CI)	No. women	Observed events	Expected events	SIR (95 % CI)
Overall	9,701	778	511	1.52 (1.42, 1.63)	3,733	458	218	2.10 (1.91, 2.30)	<0.0001
Histology
NP	7,774	552	413	1.34 (1.23, 1.45)	675	59	42	1.39 (1.06, 1.79)	0.7840
PDWA	1,613	166	84	1.99 (1.70, 2.31)	2,672	311	158	1.97 (1.76, 2.21)	0.9514
AH	314	60	14	4.16 (3.18, 5.36)	386	88	18	4.76 (3.82, 5.86)	0.4206
Type of atypia
ADH	148	26	7	3.85 (2.51, 5.64)	164	37	8	4.80 (3.38, 6.61)	0.3867
ALH	146	27	7	3.91 (2.57, 5.69)	190	45	9	4.87 (3.55, 6.52)	0.3606
ADH and ALH	17	6	1	8.59 (3.15, 18.69)	27	6	1	4.72 (1.73, 10.26)	0.3024
Age
<45	3,432	222	129	1.72 (1.50, 1.96)	943	91	43	2.12 (1.71, 2.60)	0.1004
45–55	2,602	257	166	1.55 (1.37, 1.75)	1,341	194	87	2.24 (1.94, 2.58)	0.0001
>55	3,667	299	216	1.38 (1.23, 1.55)	1,449	173	89	1.94 (1.66, 2.25)	0.0005
Involution
None	1,642	142	77	1.85 (1.56, 2.18)	608	89	33	2.67 (2.14, 3.28)	0.0076
Partial	4,116	360	233	1.55 (1.39, 1.72)	2,517	313	153	2.04 (1.82, 2.28)	0.0004
Complete	2,828	164	156	1.05 (0.90, 1.23)	474	37	26	1.43 (1.01, 1.97)	0.1049
Columnar alteration
Absent	8,391	643	448	1.43 (1.33, 1.55)	572	60	32	1.88 (1.43, 2.41)	0.0559
Present	1,306	134	62	2.15 (1.80, 2.55)	3,161	398	187	2.13 (1.93, 2.35)	0.9393
Family history
None	5,485	367	293	1.25 (1.13, 1.39)	2,021	210	119	1.77 (1.54, 2.02)	<0.0001
Weak	2,362	241	130	1.85 (1.62, 2.10)	977	144	59	2.46 (2.07, 2.90)	0.0078
Strong	1,170	149	68	2.18 (1.84, 2.55)	561	100	35	2.85 (2.31, 3.46)	0.0399

SIRs compare the observed number of breast cancer events with the number expected on the basis of Iowa SEER Data. All analyses account for the effects of age and calendar period