. 2021 Jan 21;7(3):1–8. doi: 10.1001/jamaoncol.2020.7338

Table 2. Aspirin Use at Age 70 or Above and Risk of Colorectal Cancer by Prior Duration of Use.

Variable	HR (95% CI)^a
	NHS		HPFS		Pooled analysis
	Nonregular user	Regular user	Nonregular user	Regular user	Nonregular user	Regular user
Duration of use <5 y before age 70
No. of cases/person-years	67/52 382	126/97 913	20/11 170	75/37 180	87/63 552	201/135 093
Model 1^b	1 [Reference]	1.00 (0.74-1.36)	1 [Reference]	1.03 (0.61-1.74)	1 [Reference]	1.01 (0.77-1.31)
Model 2^c	1 [Reference]	0.99 (0.73-1.34)	1 [Reference]	1.03 (0.61-1.75)	1 [Reference]	1.00 (0.77-1.30)
Model 3^d	1 [Reference]	0.98 (0.72-1.34)	1 [Reference]	1.05 (0.61-1.80)	1 [Reference]	1.00 (0.76-1.30)
Duration of use ≥5 y before age 70
No. of cases/person-years	129/116 434	237/249 978	48/23 167	229/145 677	177/139 608	466/395 655
Model 1^b	1 [Reference]	0.85 (0.68-1.06)	1 [Reference]	0.65 (0.47-0.90)	1 [Reference]	0.76 (0.59-0.99)
Model 2^c	1 [Reference]	0.84 (0.68-1.05)	1 [Reference]	0.65 (0.47-0.90)	1 [Reference]	0.76 (0.59-0.98)
Model 3^d	1 [Reference]	0.83 (0.67-1.04)	1 [Reference]	0.67 (0.48-0.93)	1 [Reference]	0.77 (0.63-0.95)

Abbreviations: HPFS, Health Professionals Follow-up Study; HR, hazard ratio; NHS, Nurses’ Health Study.

^{^a}

Values are listed as HR (95% CI) unless otherwise indicated.

^{^b}

Model 1 is conditioned on age and calendar time.

^{^c}

Model 2 is conditioned on age and calendar time, and adjusted for family history of colorectal cancer, diabetes, body mass index, alcohol consumption, physical activity, smoking pack-years, lower endoscopy, total energy intake, calcium intake, folate intake, Alternative Healthy Eating Index 2010 score, and regular use of nonsteroidal anti-inflammatory drugs, multivitamins, and menopausal hormones.

^{^d}

Model 3 includes model 2 covariates plus regular use of cholesterol-lowering drugs, hyperlipidemia, hypertension, and cardiovascular diseases.