Table 2.
Associations of NSAID exposure with breast cancer risk (E3N cohort, 2004–2014)
| Characteristics of exposure | No. of cases | HR1 (95% CI) | HR2 (95% CI) |
|---|---|---|---|
| Any NSAID | |||
| Never | 596 | 1 (reference) | 1 (reference) |
| Ever | 2268 | 1.07 (0.98–1.18) | 1.02 (0.93–1.12) |
| Never | 596 | 1 (reference) | 1 (reference) |
| Occasional | 845 | 1.06 (0.95–1.18) | 1.03 (0.92–1.15) |
| Recurrent | 1423 | 1.09 (0.98–1.20) | 1.01 (0.92–1.14) |
| Never/occasional | 1441 | 1 (reference) | 1 (reference) |
| Recurrent | 1423 | 1.05 (0.97–1.13) | 1.00 (0.92–1.08) |
| Types of NSAID | |||
| High-dose aspirin | |||
| Never/occasional use | 2763 | 1 (reference) | 1 (reference) |
| Recurrent use | 101 | 1.06 (0.87–1.29) | 1.02 (0.83–1.24) |
| Ibuprofen | |||
| Never/occasional use | 2659 | 1 (reference) | 1 (reference) |
| Recurrent use | 205 | 0.93 (0.81–1.08) | 0.91 (0.79–1.05) |
| Diclofenac | |||
| Never/occasional use | 2650 | 1 (reference) | 1 (reference) |
| Recurrent use | 214 | 1.01 (0.88–1.17) | 0.98 (0.85–1.14) |
| Piroxicam | |||
| Never/occasional use | 2651 | 1 (reference) | 1 (reference) |
| Recurrent use | 213 | 1.06 (0.92–1.22) | 1.03 (0.90–1.19) |
| Ketoprofen | |||
| Never/occasional use | 2679 | 1 (reference) | 1 (reference) |
| Recurrent use | 185 | 1.06 (0.91–1.23) | 1.02 (0.88–1.19) |
| Selective COX-2 inhibitors | |||
| Never/occasional use | 2694 | 1 (reference) | 1 (reference) |
| Recurrent use | 170 | 1.02 (0.87–1.20) | 0.98 (0.84–1.15) |
| Other NSAIDs inhibiting preferentially COX-2 | |||
| Never/occasional use | 2740 | 1 (reference) | 1 (reference) |
| Recurrent use | 124 | 1.04 (0.87–1.25) | 1.03 (0.86–1.24) |
| Other NSAIDs | |||
| Never/occasional use | 2547 | 1 (reference) | 1 (reference) |
| Recurrent use | 317 | 1.07 (0.95–1.21) | 1.04 (0.92–1.17) |
Abbreviations: CI confidence interval, COX cyclooxygenase, HR hazard ratio, NSAID nonsteroidal anti-inflammatory drug
1Adjusted only for age (time scale)
2Adjusted for age (time scale), years of schooling (baseline), alcohol intake (time-varying), body mass index (time-varying), physical activity level (baseline), age at menarche (baseline), parity and age at first birth (baseline), lifetime use of oral contraceptives (baseline), age at menopause (baseline), history of breast cancer in first-degree relatives (baseline), personal history of benign breast disease (time-varying), lifetime use of menopausal hormone therapy (time-varying), self-report of a mammogram performed during the previous follow-up cycle (time-varying), and other types of NSAIDs (except for “Any NSAID”) (time-varying). Categories used are those displayed in Table 1