Comparisons of demographic characteristics and known breast cancer risk factors in patients diagnosed with breast cancer or BBD
| All BC cases (n = 1,459) | Selected BC cases (n = 64) | BBD (n = 68) | P* | P† | |
|---|---|---|---|---|---|
| Age (mean), y | 47.9 | 47.6 | 43.2 | 0.70 | <0.01 |
| Education ≥high school, % | 45.2 | 50.0 | 51.5 | 0.51 | 0.87 |
| Age at menarche (mean), y | 14.5 | 14.6 | 14.6 | 0.52 | 0.86 |
| Postmenopause, % | 34.5 | 33.3 | 7.5 | 0.88 | <0.01 |
| Body mass index (mean) | 23.5 | 24.3 | 23.4 | 0.06 | 0.12 |
| Waist-to-hip ratio (mean) | 0.81 | 0.81 | 0.79 | 0.67 | 0.06 |
| Physical activities, % | 18.7 | 18.8 | 16.2 | 0.88 | 0.70 |
| Family history of BC among first-degree relatives | 3.7 | 6.3 | 1.5 | 0.45 | 0.15 |
Abbreviation: BC, breast cancer.
↵* The P values were for the comparisons between selected 64 breast cancer cases and the entire 1,459 breast cancer cases in the parent study and derived from the z test.
↵† The P values were for the comparisons between selected 64 breast cancer cases and 68 BBD subjects and derived from the t test for continuous variables and the χ2 test for categorical variables.