Table 2.
Association between preeclampsia and breast cancer among the nationwide cohort and KARMA cohort
| Condition | Number of breast cancer cases | IRR (95% CI) | |
|---|---|---|---|
| Model 1 | Model 2 | ||
| Nationwide cohort (N = 1,337,934) | |||
| Preeclampsia | |||
| No | 26447 | 1.00 (REF) | 1.00 (REF) |
| Yes | 1179 | 0.88 (0.83; 0.94) | 0.90 (0.85; 0.96) |
| once | 1082 | 0.90 (0.84; 0.95) | 0.91 (0.86; 0.97) |
| multiple times | 97 | 0.76 (0.62; 0.92) | 0.81 (0.66; 0.99) |
| KARMA cohort (N = 55,044) | |||
| Preeclampsia | |||
| No | 2410 | 1.00 (REF) | 1.00 (REF) |
| Yes | 86 | 0.77 (0.62; 0.95) | 0.75 (0.61; 0.93) a |
Model 1 adjusted for calendar period (10-year categories). Model 2 further adjusted for number of births, age at first birth, weight status categories, smoking status and education level. The underlying time scale was attained age. Significant associations are denoted in bold
Abbreviations: IRR incidence rate ratio, CI confidence interval
aFor model 2 in the KARMA cohort, we additionally adjusted for alcohol use, age at menarche, body shape at age 18 years, physical activity at age 18 years and irregular menstrual cycles in adult life