Table 2.

Associations between statin use and risk of invasive ductal or lobular breast cancer among women age 50 - 74 overall and among women with a history of high cholesterol

All Study Participants
	Controls (n = 877)		Ductal cases (n = 891)				Lobular cases (n = 1,036)
	No.	%	No.	%	OR	95% CI	No.	%	OR	95% CI
Never use	674	77%	664	75%	1.00	reference	782	76%	1.00	reference
Ever use for ≥6mo	190	22%	206	23%	1.16	0.92 - 1.47	237	23%	1.22	0.98 - 1.53
Duration of ever use
6mo - <5yrs	104	12%	93	11%	0.93	0.68 - 1.26	122	12%	1.12	0.84 - 1.49
5yrs - <10yrs	50	6%	57	6%	1.26	0.84 - 1.89	51	5%	1.03	0.68 - 1.56
≥ 10 yrs	35	4%	53	6%	1.72	1.10 - 2.71	62	6%	1.82	1.17 - 2.82
p-value for trend					p = 0.173				p = 0.090
Recency of use
Former use	20	2%	20	2%	1.12	0.59 - 2.13	19	2%	1.02	0.53 - 1.95
Current use	170	19%	184	21%	1.16	0.91 - 1.15	218	21%	1.25	0.98 - 1.57
Duration of current use
6mo - <5yrs	91	10%	79	9%	0.90	0.65 - 1.24	109	11%	1.13	0.83 - 1.53
5yrs - <10yrs	47	5%	54	6%	1.26	0.83 - 1.91	47	5%	1.00	0.65 - 1.53
≥ 10 yrs	31	4%	50	6%	1.83	1.14 - 2.93	60	6%	1.97	1.25 - 3.12
p-value for trend					p = 0.043				p = 0.021
Study Participants with a History of High Cholesterol
	Controls (n = 273)		Ductal cases (n = 286)				Lobular cases (n = 320)
	No.	%	No.	%	OR	95% CI	No.	%	OR	95% CI
Never use	85	31%	71	25%	1.00	Ref	77	24%	1.00	Ref
Ever use for ≥6mo	175	64%	195	68%	1.42	0.96 - 2.09	227	71%	1.64	1.12 - 2.41
Current use	158	57.9	175	61%	1.41	0.95 - 2.08	208	65%	1.63	1.11 - 2.41
Duration of ever use
6mo - <5yrs	93	34%	88	31%	1.19	0.77 - 1.84	116	37%	1.55	1.01 - 2.37
5yrs - <10yrs	48	18%	54	19%	1.46	0.87 - 2.44	48	15%	1.31	0.77 - 2.22
≥ 10 yrs	33	12%	51	18%	2.04	1.17 - 3.57	61	19%	2.43	1.40 - 4.21
p-value for trend					p = 0.025				p = 0.006

OR: odds ratio adjusted for reference year, reference age, county of residence, and HRT