Table 3.

Incidence of colorectal cancer after initiation of regular nonsteroidal anti-inflammatory drug use in the Physician’s Health Study

				Age-adjusted		Fully-adjusted* without arthritis		Fully-adjusted* including arthritis
Duration of regular non-aspirin NSAID use after initiation	Person-years	Events	IR per 100,000 p-y	RR	95% CI	RR	95% CI	RR	95% CI
Never	311,615	411	132	1.0	reference	1.0	reference	1.0	reference
1 year	26,235	43	164	1.1	0.8 – 1.5	1.1	0.8 – 1.5	1.1	0.8 – 1.6
2 years	10,411	15	144	0.9	0.5 – 1.5	0.9	0.5 – 1.5	1.0	0.6 – 1.7
3 years	5,814	9	155	1.0	0.5 – 1.8	0.9	0.5 – 1.8	1.1	0.5 – 2.1
4 years	3,802	6	158	1.0	0.4 – 2.1	0.9	0.4 – 2.0	1.0	0.5 – 2.3
5 or more years	7,947	11	138	0.9	0.5 – 1.6	0.8	0.4 – 1.5	0.9	0.5 – 1.7
Duration of regular all NSAIDs use after initiation
Never	240,900	307	127	1.0	reference	1.0	reference	1.0	reference
1 year	42,649	57	134	0.9	0.7 – 1.2	0.9	0.6 – 1.2	0.9	0.6 – 1.2
2 years	24,911	36	145	0.9	0.6 – 1.3	0.9	0.6 – 1.3	0.9	0.6 – 1.3
3 years	17,176	22	128	0.7	0.5 – 1.2	0.7	0.4 – 1.1	0.7	0.5 – 1.2
4 years	12,108	23	190	1.2	0.7 – 1.8	1.1	0.7 – 1.7	1.2	0.7 – 1.9
5 or more years	28,079	50	178	1.0	0.7 – 1.4	0.9	0.7 – 1.4	1.0	0.7 – 1.5

^*Rate ratios and their 95% confidence intervals from time-varying Cox proportional hazards model controlling for all variables presented in table 2: age (continuous, linear and squared), body mass index (continuous), vigorous exercise (5 categories), smoking (never, former, current), alcohol consumption (6 categories), multivitamin use, consumption of fruits and vegetables (servings per day, continuous), as well as history of hypertension, diabetes, coronary artery disease (myocardial infarction, coronary artery bypass grafting, or percutaneous transluminal coronary angioplasty), angina, headache, migraine, peptic ulcer, gastrointestinal bleeding, and gastritis; variables are updated during follow-up whenever possible