Table 3.
Estimated Lifetime Duration and Number of Aspirin Tablets and Incidence of Ovarian Cancer in the Nurses’ Health Study (1980–2004)
| NHS |
|||||
| Cases, no.a | Hazard Ratiob | 95% Confidence Intervalb | Hazard Ratioc | 95% Confidence Intervalc | |
| Total duration or regular use, year(s) | |||||
| <1 | 248 | 1.00 | 1.00 | ||
| 1–<5 | 120 | 1.21 | 0.97, 1.52 | 1.21 | 0.97, 1.52 |
| 5–<10 | 67 | 1.12 | 0.84, 1.48 | 1.11 | 0.83, 1.47 |
| 10–<20 | 42 | 0.87 | 0.62, 1.22 | 0.86 | 0.61, 1.21 |
| ≥20 | 68 | 1.01 | 0.77, 1.33 | 1.02 | 0.77, 1.33 |
| Ptrendd | 0.59 | 0.60 | |||
| Total no. of tablets | |||||
| <500 | 279 | 1.00 | 1.00 | ||
| 500–999 | 59 | 1.62 | 1.22, 2.16 | 1.62 | 1.22, 2.16 |
| 1,000–2,999 | 79 | 1.20 | 0.92, 1.55 | 1.19 | 0.92, 1.54 |
| 3,000–4,999 | 29 | 0.80 | 0.54, 1.18 | 0.80 | 0.54, 1.17 |
| ≥5,000 | 97 | 1.00 | 0.79, 1.26 | 1.00 | 0.79, 1.27 |
| Ptrendd | 0.53 | 0.57 | |||
Abbreviation: NHS, Nurses’ Health Study.
a
Numbers may not add up to the total number of cases because of participants with missing information on aspirin duration or dose.
b
Models stratified by age in months and 2-year questionnaire cycles.
c
Models stratified by age in months and 2-year questionnaire cycles and adjusted for duration of oral contraceptive use, parity, tubal ligation, menopausal status, and postmenopausal hormone use.
d
P values (Wald statistics) using continuous measures of duration (years) and number of tablets.