. 2008 Apr 30;10(2):R38. doi: 10.1186/bcr2089

Table 5.

Association between nonsteroidal anti-inflammatory drug (NSAID) use and breast cancer according to stage, National Institutes of Health–AARP Study

	In situ breast cancer					Invasive breast cancer

NSAID use	Number of cancers	Person-years	Relative risk^a	95% confidence interval	P value for trend	Number of cancers	Person-years	Relative risk^a	95% confidence interval	P value for trend
Aspirin use^b
Never	298	280,077	1.00 (referent)		0.02	1,254	283,247	1.00 (referent)		0.37
<1/week	233	261,641	0.80	0.67 to 0.96		1,166	264,821	0.99	0.91 to 1.07
1–6/week	124	131,305	0.85	0.69 to 1.05		589	132,899	0.98	0.88 to 1.08
1+/day	122	143,137	0.78	0.63 to 0.96		648	144,854	0.96	0.87 to 1.06
Non-aspirin NSAID use^b
Never	292	324,890	1.00 (referent)		0.45	1,463	328,884	1.00 (referent)		0.88
<1/week	269	258,097	1.14	0.96 to 1.35		1,140	261,013	0.97	0.90 to 1.05
1–6/week	122	124,433	1.06	0.85 to 1.31		569	125,934	1.01	0.92 to 1.12
1+/day	91	107,466	0.87	0.69 to 1.10		494	108,757	0.98	0.89 to 1.09

^aAdjusted for age (continuous), race, age at first birth, hormone therapy use, number of breast biopsies, alcohol intake, history of hypertension, and family history of breast cancer in first-degree relative.

^bThese models also include terms for frequency of use of opposite NSAID type.