Table 5.
Multivariable model of best predictors of surgically-treated fibroids (presented in order selected by stepwise Cox proportional hazards modeling) in the California Teachers Study.
| Surgery for fibroids during study follow-up period, 1995-2006 | |
|---|---|
| Multivariable adjusted RR (95% CI)*a | |
| Menopausal hormone status | |
| Premenopausal | 5.33 (3.62, 7.85) |
| Perimenopausal | 2.89 (1.77, 4.74) |
| Postmenopausal, never used hormone therapy | 1.00 |
| Postmenopausal, used estrogen alone | 2.01 (1.16, 3.50) |
| Postmenopausal, used combined estrogen- progestin | 2.34 (1.63, 3.36) |
| Postmenopausal, mixed hormone therapy use | 3.18 (2.03, 4.96) |
| Age at first full-term pregnancy (years) | |
| Nulliparous | 1.20 (1.06, 1.36) |
| 14-19 | 1.12 (0.85, 1.47) |
| 20-24 | 1.28 (1.11, 1.46) |
| 25-29 | 1.00 |
| 30-34 | 0.77 (0.65, 0.90) |
| ≥35 | 0.59 (0.45, 0.78) |
| Race/Ethnicity | |
| White | 1.00 |
| African American | 2.14 (1.69, 2.71) |
| Latina | 1.28 (1.07, 1.54) |
| Asian/Pacific Islander | 1.15 (0.91, 1.44) |
| Mother or sister had fibroids | |
| No | 1.00 |
| Yes | 1.37 (1.21, 1.55) |
| Adopted/unknown | |
| Body mass index (kg/m2) | |
| Underweight (<18.5) | 1.00 (0.74, 1.35) |
| Normal weight (18.5-24.9) | 1.00 |
| Overweight (25-29.9) | 1.23 (1.10, 1.38) |
| Obese (≥30) | 1.27 (1.11, 1.46) |
| Daily alcohol intake (g) | |
| None | 0.94 (0.84, 1.04) |
| <20 | 1.00 |
| ≥20 | 1.36 (1.14, 1.61) |
| Ever had difficulty becoming pregnant | |
| No | 1.00 |
| Yes | 1.23 (1.10, 1.38) |
| Cigarette smoker | |
| Never | 1.00 |
| Former | 0.87 (0.77, 0.97) |
| Current | 0.65 (0.50, 0.85) |
| Diabetes | |
| No | 1.00 |
| Yes | 0.51 (0.32, 0.82) |
| High blood pressure | |
| No | 1.00 |
| Yes | 1.19 (1.01, 1.40) |
| Ever had tubal ligation | |
| No | 1.00 |
| Yes | 1.19 (1.05, 1.35) |
| Age at menarche (years) | |
| ≤10 | 1.21 (1.00, 1.45) |
| 11 | 1.17 (1.01, 1.35) |
| 12 | 1.03 (0.91, 1.16) |
| 13 | 1.00 |
| 14 | 0.95 (0.80, 1.12) |
| ≥15 | 0.93 (0.76, 1.13) |
*
RR, relative risk; CI, confidence interval.
a
Stratified by age and adjusted for all the other variables in the table.