Table 2.
Associations between risk/protective factors and ovarian cancer that differed by menopausal status among women aged 45-54 years
| Risk/protective factor | All women aged 45-54 years (pre- and postmenopausal combined) |
Premenopausal women aged 45-54 years |
Postmenopausal women aged 45-54 years |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Case participants,a No. | Control participants,a No. | ORb (95% CI) | Case participants,a No. | Control participants,a No. | ORb(95% CI) | Case participants,a No. | Control participants,a No. | ORb (95% CI) | P- interaction c | Interaction criteria metd | |
| Breastfeeding | |||||||||||
| Never | 1212 | 1278 | 1.0 | 693 | 763 | 1.0 | 519 | 515 | 1.0 | ||
| <12 months | 551 | 978 | 0.76 (0.64 to 0.89) | 327 | 595 | 0.78 (0.62 to 0.98) | 224 | 383 | 0.71 (0.55 to 0.92) | ||
| ≥12 months | 397 | 998 | 0.59 (0.49 to 0.72) | 240 | 706 | 0.53 (0.42 to 0.68) | 157 | 292 | 0.69 (0.51 to 0.94) | .064 | (b), (c), (d) |
| Depot-medroxyprogesterone acetate use | |||||||||||
| No | 1886 | 2793 | 1.0 | 1109 | 1793 | 1.0 | 777 | 1000 | 1.0 | ||
| Yes | 21 | 76 | 0.61 (0.36 to 1.02) | 10 | 52 | 0.51 (0.26 to 1.00) | 11 | 24 | 0.80 (0.38 to 1.69) | .35 | (b), (c), (d) |
| First-degree family history of ovarian cancer | |||||||||||
| No | 1610 | 2548 | 1.0 | 943 | 1633 | 1.0 | 667 | 915 | 1.0 | ||
| Yes | 119 | 87 | 2.15 (1.56 to 2.97) | 69 | 48 | 2.43 (1.58 to 3.73) | 50 | 39 | 1.83 (1.15 to 2.91) | .39 | (b), (c), (d) |
| Endometriosis | |||||||||||
| No | 1889 | 3058 | 1.0 | 1128 | 1981 | 1.0 | 761 | 1077 | 1.0 | ||
| Yes | 269 | 255 | 1.60 (1.32 to 1.95) | 135 | 123 | 1.94 (1.47 to 2.57) | 134 | 132 | 1.33 (1.00 to 1.76) | .041 | (a), (b), (c), (d) |
Numbers may not sum to total because of missing values. CI = confidence interval; OR = odds ratio.
Pooled estimates from logistic regression models in the 50 imputed datasets, adjusted for age at diagnosis for cases/reference age for controls (45-49 years vs 50-54 years), race/ethnicity, education level, and Ovarian Cancer Association Consortium study.
P value for interaction between risk or protective factor and menopausal status using the likelihood ratio test.
Criteria to assess interactions: (a) P < .05 for interaction; (b) odds ratios of a factor across the levels of the other factor are consistent, and the differences in magnitude are large; (c) the interaction is biologically plausible; and (d) the prevalence of the risk factors is large enough so that the interaction would have a meaningful impact on the risk stratification model.