Table 3.
Associations of NSAID recurrent use with breast cancer, according to characteristics of use (E3N cohort, 2004–2014)
| Characteristics of exposure | No. of cases | HR1 (95% CI) | Ptrend2 |
|---|---|---|---|
| Cumulative number of DDDs | 0.67 | ||
| Never/occasional use of NSAIDs | 1441 | 1 (reference) | |
| ≤ 200 | 763 | 1.02 (0.93–1.12) | |
| > 200 to ≤ 400 | 89 | 0.93 (0.75–1.16) | |
| > 400 to ≤ 600 | 22 | 1.28 (0.84–1.95) | |
| > 600 | 43 | 1.02 (0.75–1.39) | |
| Unknown | 506 | 0.96 (0.91–1.13) | |
| Cumulative duration of use, months | 0.92 | ||
| Never/occasional use of NSAIDs | 1441 | 1 (reference) | |
| ≤ 3 | 516 | 1.00 (0.91–1.11) | |
| > 3 to ≤ 6 | 256 | 1.05 (0.91–1.20) | |
| > 6 to ≤ 12 | 89 | 1.02 (0.82–1.27) | |
| > 12 | 73 | 1.03 (0.81–1.31) | |
| Unknown | 489 | 0.96 (0.87–1.07) | |
| Time since first use, years | 0.85 | ||
| Never/occasional use of NSAIDs | 1441 | 1 (reference) | |
| ≤ 4 | 491 | 1.00 (0.90–1.11) | |
| > 4 to ≤ 6 | 201 | 1.07 (0.92–1.25) | |
| > 4 to ≤ 8 | 138 | 1.04 (0.86–1.25) | |
| > 8 | 249 | 0.88 (0.76–1.02) | |
| Unknown | 344 | 1.01 (0.90–1.14) | |
| Age at first use, years | 0.85 | ||
| Never/occasional use of NSAIDs | 1441 | 1 (reference) | |
| ≤ 60 | 461 | 0.97 (0.86–1.09) | |
| > 60 to ≤ 65 | 292 | 1.06 (0.93–1.22) | |
| > 65 to ≤ 70 | 215 | 1.03 (0.88–1.20) | |
| > 70 | 154 | 1.03 (0.85–1.24) | |
| Unknown | 301 | 0.95 (0.83–1.09) | |
| Time since last use, years | 0.79 | ||
| Never/occasional use of NSAIDs | 1441 | 1 (reference) | |
| Current use | 845 | 1.01 (0.93–1.11) | |
| > Current use to ≤ 2 | 330 | 1.02 (0.91–1.16) | |
| > 2 to ≤ 5 | 103 | 0.99 (0.81–1.22) | |
| > 5 | 57 | 0.85 (0.65–1.11) | |
| Unknown | 88 | 0.89 (0.72–1.11) | |
| Average daily dose | 0.18 | ||
| Never/occasional use of NSAIDs | 1441 | 1 (reference) | |
| ≤ 1 DDD | 445 | 1.03 (0.92–1.14) | |
| > 1 to ≤ 1.5 DDD | 587 | 1.02 (0.92–1.13) | |
| > 1.5 to ≤ 2 DDDs | 200 | 0.96 (0.83–1.12) | |
| > 2 DDDs | 55 | 0.95 (0.73–1.25) | |
| Unknown | 136 | 0.90 (0.76–1.08) | |
Abbreviations: CI confidence interval, DDD defined daily dose, HR hazard ratio, NSAID nonsteroidal anti-inflammatory drug
1Adjusted 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 use (time-varying), and self-report of a mammogram performed during the previous follow-up cycle (time-varying). Categories used are those displayed in Table 1. HRs were obtained from separate models including one characteristic of exposure at a time
2Tests for linear trends were performed among exposed women with known characteristics of exposure. The characteristics of use were considered as continuous variables