Table 1. Age-standardised baseline characteristics of 36 777 women from the Swedish Mammography Cohort by tertiles of dietary PCB exposure.
| Tertiles of dietary PCB exposure range (median) ng per daya | <139 (110) | 139–193 (162) | >193 (256) |
|---|---|---|---|
| Age (years) | 62±10 | 60±9 | 63±9 |
| Postsecondary education (%) | 25 | 27 | 26 |
| Family history of breast cancer (%) | 9 | 9 | 9 |
| History of diabetes (%) | 5 | 4 | 6 |
| BMI (kg m−2) | 25±4 | 25±4 | 25±4 |
| Weight loss >5 kg within 1 year (%) | 68 | 69 | 70 |
| Age at menarche ⩽12 years (%) | 28 | 27 | 29 |
| Ever use of oral contraceptives (%) | 55 | 58 | 58 |
| Nulliparous (%) | 10 | 9 | 9 |
| Age at first birth ⩾30 years (%) | 12 | 11 | 10 |
| Premenopausal (%) | 11 | 12 | 11 |
| Age at menopause ⩾51 years (%) | 42 | 43 | 43 |
| Ever use of postmenopausal hormones (%) | 50 | 52 | 51 |
| Current smoker (%) | 24 | 22 | 24 |
| Leisure-time daily physical activity (%) | |||
| ⩽2 h sitting/watching TV | 56 | 55 | 56 |
| >40 min walking/bicycling | 36 | 35 | 36 |
| Alcohol consumption (%) | |||
| No use | 22 | 14 | 16 |
| >15 g per day | 7 | 9 | 9 |
| Total energy intake (kcal per day) | 1780±5 | 1710±4 | 1710±5 |
| EPA-DHA intake (mg per day) | 164±68 | 289±54 | 555±326 |
Abbreviations: BMI=body mass index; EPA-DHA=eicosapentaenoic acid-docosahexaenoic acid; PCB=polychlorinated biphenyl.
a
Adjusted for total energy intake.
Note: All variables are expressed as mean±s.d. or percentage (%).