Table 3.
Hazard ratios (95% confidence intervals) of total and cause specific mortality by duration of oral contraceptive use (years) compared with never users among 121 337 participants in the Nurses’ Health Study, 1976-2012
| Cause of death | Duration of oral contraceptive use (years) | P for trend | ||||
|---|---|---|---|---|---|---|
| ≤1 | >1 to <2 | ≥2 to <5 | ≥5 to <10 | ≥10 | ||
| All causes* (n=31 237) | 1.01 (0.97 to 1.05) | 1.01 (0.94 to 1.08) | 1.02 (0.97 to 1.06) | 1.05 (1.00 to 1.09) | 1.05 (0.99 to 1.12) | 0.02 |
| Breast cancer† (n=2295) | 1.06 (0.93 to 1.22) | 1.05 (0.84 to 1.33) | 1.03 (0.89 to 1.21) | 1.20 (1.03 to 1.40) | 1.27 (1.03 to 1.56) | 0.003 |
| Breast cancer, further adjusted‡ | 1.05 (0.91 to 1.21) | 1.06 (0.84 to 1.33) | 1.05 (0.90 to 1.23) | 1.26 (1.09 to 1.46) | 1.39 (1.13 to 1.71) | <0.0001 |
| Ovarian cancer† (n=851) | 0.89 (0.70 to 1.12) | 0.96 (0.67 to 1.39) | 0.99 (0.78 to 1.25) | 0.70 (0.53 to 0.92) | 0.60 (0.39 to 0.92) | 0.002 |
| Ovarian cancer, further adjusted§ | 0.89 (0.71 to 1.12) | 0.96 (0.67 to 1.39) | 0.98 (0.77 to 1.25) | 0.69 (0.53 to 0.92) | 0.60 (0.40 to 0.93) | 0.002 |
| Cerebrovascular disease¶ (n=1639) | 0.73 (0.60 to 0.90) | 0.89 (0.63 to 1.25) | 0.89 (0.72 to 1.11) | 0.98 (0.79 to 1.19) | 1.21 (0.94 to 1.56) | 0.26 |
| Violence/accidents** (n=1083) | 1.35 (1.12 to 1.64) | 0.81 (0.55 to 1.19) | 1.12 (0.90 to 1.40) | 0.94 (0.74 to 1.20) | 1.13 (0.83 to 1.55) | 0.94 |
| Suicide** (n=240) | 1.36 (0.91 to 2.02) | 0.99 (0.51 to 1.93) | 1.55 (1.05 to 2.30) | 0.84 (0.51 to 1.39) | 1.83 (1.07 to 3.15) | 0.26 |
| Other diseases* (n=9195) | 1.05 (0.98 to 1.14) | 1.02 (0.89 to 1.16) | 1.04 (0.96 to 1.13) | 1.05 (0.97 to 1.14) | 1.11 (1.00 to 1.24) | 0.04 |
*Adjusts for model 3 variables: base model+mortality risk factors.
†Adjusts for model 3 variables: base model+cancer risk factors+mortality risk factors.
‡Adjusts for model 4 variables: base model+cancer risk factors+mortality risk factors+breast cancer risk factors (parity, age at first birth, hormone therapy use, duration of hormone therapy, and history of benign breast disease).
§Adjusts for model 4 variables: base model+cancer risk factors+mortality risk factors+ovarian cancer risk factors (parity, tubal ligation, and hysterectomy).
¶Adjusts for model 3 variables: sociodemographics+cardiovascular risk factors+mortality risk factors.
**Adjusts for model 3 variables: sociodemographics+violent/accident death risk factors+mortality risk factors.