Table 1. Characteristics of postmenopausal women by NSAID use, Group Health, 1996-2006.
| Characteristics | Nonuser (n = 20,653), % |
Initiator (n = 5,978), % |
Discontinuer (n = 1,156), % |
Continuer (n = 838), % |
Mixed (n = 659), % |
P * |
|---|---|---|---|---|---|---|
| % Women in each category | 70.5 | 20.4 | 4.0 | 2.9 | 2.2 | |
| Age at first mammogram (y) |
||||||
| ≤49 | 8.5 | 7.1 | 8.1 | 4.4 | 6.8 | <0.0001 |
| 50-59 | 38.3 | 30.4 | 33.3 | 24.4 | 26.6 | |
| 60-69 | 28.9 | 27.9 | 29.0 | 27.9 | 28.1 | |
| 70-79 | 18.9 | 26.9 | 23.6 | 32.7 | 30.2 | |
| 80-98 | 5.4 | 7.7 | 6.0 | 10.6 | 8.3 | |
| Age at second mammogram (y) | ||||||
| ≤49 | 5.3 | 4.4 | 6.0 | 2.8 | 4.4 | <0.0001 |
| 50-59 | 35.3 | 27.8 | 30.2 | 22.1 | 25.0 | |
| 60-69 | 30.5 | 28.4 | 29.5 | 25.9 | 26.4 | |
| 70-79 | 21.4 | 28.2 | 25.2 | 34.0 | 31.9 | |
| 80-100 | 7.5 | 11.2 | 9.1 | 15.2 | 12.3 | |
| Race | ||||||
| White | 89.1 | 89.3 | 88.1 | 90.1 | 89.8 | 0.056 |
| Black | 6.9 | 6.9 | 7.0 | 5.6 | 5.3 | |
| American Indian/Alaska Native | 2.1 | 2.3 | 3.0 | 2.9 | 3.3 | |
| Asian/Hawaiian/Pacific Islander | 1.5 | 1.2 | 1.6 | 1.2 | 0.8 | |
| Unknown | 0.4 | 0.3 | 0.3 | 0.2 | 0.8 | |
| Ethnicity | ||||||
| Hispanic | 3.3 | 3.9 | 4.2 | 3.1 | 4.2 | 0.15 |
| Not Hispanic | 96.3 | 95.7 | 95.2 | 96.2 | 95.0 | |
| Unknown | 0.4 | 0.4 | 0.6 | 0.7 | 0.8 | |
| BMI (at first mammogram) | ||||||
| <25 | 42.7 | 34.3 | 36.0 | 29.6 | 25.5 | <0.0001 |
| 25-30 | 30.5 | 32.2 | 30.5 | 31.6 | 30.3 | |
| >30 | 22.8 | 29.0 | 29.8 | 34.4 | 38.1 | |
| Unknown | 4.0 | 4.5 | 3.6 | 4.4 | 6.1 | |
| BI-RADS category at first mammogram |
||||||
| Entirely fat (1) | 9.3 | 11.2 | 9.2 | 13.8 | 10.6 | <0.0001 |
| Scattered fibroglandular (2) | 43.8 | 47.6 | 47.2 | 50.1 | 51.0 | |
| Heterogeneously dense (3) | 39.5 | 35.5 | 38.0 | 31.9 | 33.1 | |
| Extremely dense (4) | 7.4 | 5.7 | 5.6 | 4.2 | 5.3 | |
| BI-RADS category at second mammogram |
||||||
| Entirely fat (1) | 7.6 | 9.5 | 7.4 | 10.7 | 11.4 | <0.0001 |
| Scattered fibroglandular (2) | 43.1 | 46.9 | 48.9 | 49.6 | 46.4 | |
| Heterogeneously dense (3) | 42.5 | 38.4 | 39.5 | 35.6 | 37.5 | |
| Extremely dense (4) | 6.8 | 5.2 | 4.2 | 4.1 | 4.7 | |
| HRT use | ||||||
| Nonuser | 26.6 | 23.1 | 23.3 | 21.2 | 19.6 | <0.0001 |
| Initiator | 1.9 | 2.3 | 1.5 | 2.1 | 1.5 | |
| Discontinuer | 31.0 | 30.8 | 32.4 | 31.2 | 30.8 | |
| Continuer | 40.3 | 43.6 | 42.6 | 45.0 | 47.5 | |
| Unknown | 0.2 | 0.2 | 0.2 | 0.5 | 0.6 | |
| Days between exams | ||||||
| Mean | 634.9 | 632.3 | 639.1 | 613.3 | 619.3 | <0.0001 |
| SD | 130.5 | 125.7 | 128.5 | 137.8 | 135.7 | |
| Median | 676 | 670 | 674 | 661 | 671 | |
| Age at menarche (y) | ||||||
| Never | 0.3 | 0.4 | 0.4 | 0.7 | 0.5 | <0.0001 |
| <11 | 5.6 | 6.1 | 7.0 | 8.9 | 6.4 | |
| 11-14 | 72.2 | 73.5 | 70.0 | 73.4 | 77.2 | |
| ≥15 | 10.5 | 10.8 | 12.0 | 9.2 | 8.0 | |
| Unknown | 11.4 | 9.2 | 10.6 | 7.8 | 7.9 | |
| Family history | ||||||
| No family history | 58.7 | 60.7 | 57.5 | 55.5 | 57.4 | 0.0004 |
| First-degree relative | 17.8 | 17.7 | 19.9 | 22.1 | 19.9 | |
| Second-degree relative | 14.3 | 14.1 | 13.8 | 12.8 | 13.8 | |
| Unknown | 9.2 | 7.5 | 8.8 | 9.6 | 8.9 | |
| Age at first birth (y) | ||||||
| Not parous | 15.1 | 13.1 | 13.4 | 10.9 | 12.8 | <0.0001 |
| ≤19 | 16.6 | 20.1 | 19.8 | 21.7 | 21.8 | |
| 20-24 | 37.7 | 37.8 | 39.4 | 39.3 | 41.7 | |
| 25-29 | 19.1 | 18.2 | 17.6 | 18.4 | 16.7 | |
| ≥30 | 9.5 | 9.0 | 7.5 | 7.0 | 5.5 | |
| Unknown | 2.0 | 1.8 | 2.3 | 2.7 | 1.5 |
*
P values calculated from χ2 tests of independence between NSAID use category and each calculated for categorical characteristics and from ANOVA for continuous variables.