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. Author manuscript; available in PMC: 2022 Sep 1.
Published in final edited form as: Cancer. 2021 May 11;127(17):3145–3155. doi: 10.1002/cncr.33623

Table 5.

Aspirin/Ibuprofen Use and the Risk of Colorectal Cancer in the PLCO Cancer Screening Trial

NSAID use
(times/month)
Controls Colorectal Cancer Overall Proximal Colon Distal Colon Rectum
Cases HR (95% CI)* Cases HR (95% CI)* Cases HR (95% CI)* Cases HR (95% CI)*
Aspirin ^
 <4 75905 1817 1.00 970 1.00 504 1.00 315 1.00
 4 - <30 16084 309 0.79 (0.70, 0.89) 169 0.80 (0.68, 0.94) 78 0.73 (0.57, 0.93) 57 0.86 (0.64, 1.14)
 ≥30 32639 700 0.88 (0.81, 0.96) 378 0.89 (0.79, 1.00) 180 0.82 (0.69, 0.98) 133 0.97 (0.79, 1.19)
P, trend <0.0001 0.008 0.003 0.39
Ibuprofen ^
 <4 101210 2375 1.00 1272 1.00 643 1.00 423 1.00
 4 - <30 11432 231 0.92 (0.80, 1.05) 133 0.98 (0.82, 1.18) 57 0.84 (0.64, 1.11) 40 0.88 (0.63, 1.23)
 ≥30 11986 220 0.81 (0.70, 0.93) 112 0.75 (0.62, 0.91) 62 0.87 (0.66, 1.13) 42 0.92 (0.67, 1.27)
P, trend 0.003 0.0091 0.23 0.38
Combined use
 <4 61849 1545 1.00 824 1.00 422 1.00 275 1.00
 4 - <30 22035 432 0.79 (0.71, 0.88) 240 0.82 (0.71, 0.94) 113 0.76 (0.62, 0.94) 73 0.75 (0.58, 0.98)
 30 - <60 25437 550 0.85 (0.77, 0.94) 293 0.84 (0.73, 0.96) 145 0.84 (0.69, 1.02) 105 0.91 (0.73, 1.15)
 ≥60 15307 299 0.79 (0.69, 0.89) 160 0.77 (0.65, 0.92) 82 0.81 (0.64, 1.04) 52 0.82 (0.60, 1.10)
P, trend <0.0001 0.0003 0.02 0.15
*

Hazard ratio (HR) and 95% confidence interval (CI) calculated by Cox proportional hazards regression adjusted for study center, race, sex, family history of colorectal cancer, smoking history, body mass index, trial arm, and calendar year at baseline (age was the underlying time metric)

^

Aspirin use is adjusted for Ibuprofen use and vice versa