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Table 2 Adjusted hazard ratios (HRs) and 95% confidence intervals (CI) of breast cancer risk comparing regular medication users with non-regular users in the Prospective Family Study Cohort

From: Regular use of aspirin and other non-steroidal anti-inflammatory drugs and breast cancer risk for women at familial or genetic risk: a cohort study

  Number of events Person-years Model 1a Model 2b Model 3c Model 4d
Medication HR (95% CI) HR (95% CI) HR (95% CI) HR (95% CI)
Aspirin-based medications
Prospective cohorte
  Non-regular user 124 23,545 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 15 4378 0.57 (0.32, 1.00) 0.56 (0.32, 1.00) 0.55 (0.29, 1.06) 0.61 (0.33, 1.14)
Combined cohortf
  Non-regular user 1838 236,452 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 503 71,610 0.57 (0.51, 0.63) 0.57 (0.51, 0.63) 0.60 (0.54, 0.67) 0.63 (0.57, 0.71)
COX-2 inhibitors
Prospective cohorte
  Non-regular user 133 25,203 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 6 2519 0.39 (0.17, 0.90) 0.38 (0.16, 0.88) 0.37 (0.14, 0.94) 0.39 (0.15, 0.97)
Combined cohortf
  Non-regular user 2236 274,964 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 66 29,076 0.25 (0.20, 0.32) 0.26 (0.20, 0.33) 0.28 (0.22, 0.36) 0.29 (0.23, 0.38)
Ibuprofen and other NSAIDsg
Prospective cohorte
  Non-regular user 116 23,081 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 22 4645 0.93 (0.57, 1.52) 0.94 (0.57, 1.54) 1.04 (0.61, 1.76) 1.24 (0.72, 2.12)
Combined cohortf
  Non-regular user 1836 248,675 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 459 55,695 0.79 (0.71, 0.88) 0.80 (0.72, 0.89) 0.84 (0.76, 0.94) 0.93 (0.83, 1.04)
Ibuprofen-based medicationsh
Prospective cohorte
  Non-regular user 39 8170 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 11 2888 0.68 (0.34, 1.37) 0.69 (0.35, 1.39) 0.84 (0.42, 1.69) 0.99 (0.49, 2.01)
Combined cohortf
  Non-regular user 1685 134,961 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 439 42,044 0.77 (0.61, 0.96) 0.74 (0.59, 0.94) 0.81 (0.64, 1.02) 0.83 (0.65, 1.05)
Acetaminophen-based medications
Prospective cohorte
  Non-regular user 116 23,415 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 23 4370 0.96 (0.61, 1.53) 1.00 (0.63, 1.60) 0.86 (0.49, 1.49) 0.96 (0.55, 1.65)
Combined cohortf
  Non-regular user 1985 250,745 1.00 (ref) 1.00 (ref) 1.00 (ref) 1.00 (ref)
  Regular user 318 54,649 0.82 (0.73, 0.93) 0.82 (0.73, 0.93) 0.83 (0.73, 0.95) 0.98 (0.85, 1.12)
  1. aModel 1 is adjusted for race/ethnicity, study center, and baseline age; stratified by birth cohort
  2. bModel 2 is further adjusted for familial risk profile
  3. cModel 3 is further adjusted for cigarette smoking, alcohol consumption, hormone therapy use, and hormonal birth control use
  4. dModel 4 is further adjusted for regular use of the other types of medication. For example, the Model 4 estimates for regular aspirin use are adjusted for regular use of COX-2 inhibitors, ibuprofen and other NSAIDs, and acetaminophen
  5. eIncludes women with no personal history of breast cancer when regular medication use was asked by questionnaire (N = 5606)
  6. fIncludes retrospective breast cancer cases (diagnosed prior to baseline and/or follow-up questionnaire) and prospective breast cancer cases (diagnosed after follow-up questionnaire) (N = 8233)
  7. gNon-steroidal anti-inflammatory drugs
  8. hkConFab participants are excluded from these models because they were only asked about regular use of other NSAIDs, including ibuprofen, but not about ibuprofen specifically