Age-standardized baseline characteristics of study participants in relation to total energy intake
| Characteristic | Quartile of energy intake | |||||||
|---|---|---|---|---|---|---|---|---|
| Q1 (n = 6,885) | Q2 (n = 6,885) | Q3 (n = 6,886) | Q4 (n = 6,885) | |||||
| Range of energy intake (kcal/d) | <1,316 | 1,316-1,656 | 1,657-2,083 | ≥2,084 | ||||
| Age (y)* | 63.1 ± 5.3 | 63.0 ± 5.4 | 63.0 ± 5.4 | 62.5 ± 5.3 | ||||
| BMI (kg/m2)* | 26.5 ± 5.1 | 26.7 ± 5.2 | 27.0 ± 5.4 | 27.8 ± 5.8 | ||||
| Height (m)* | 1.63 ± 0.07 | 1.63 ± 0.06 | 1.63 ± 0.07 | 1.64 ± 0.07 | ||||
| Recreational physical activity (%), h/wk | ||||||||
| Never | 17.7 | 14.3 | 14.2 | 15.0 | ||||
| <1 | 19.8 | 18.2 | 18.3 | 17.9 | ||||
| 1 | 12.2 | 12.1 | 12.0 | 11.7 | ||||
| 2 | 16.1 | 16.9 | 17.7 | 16.7 | ||||
| 3 | 15.7 | 17.1 | 17.3 | 16.4 | ||||
| ≥4 | 18.5 | 21.4 | 20.5 | 22.3 | ||||
| Family history of breast cancer† (%) | 13.6 | 14.4 | 13.7 | 13.9 | ||||
| Mammography in past 3 y (%) | ||||||||
| Never | 8.8 | 7.7 | 8.2 | 9.7 | ||||
| Once | 18.9 | 18.2 | 18.2 | 19.7 | ||||
| More than once | 72.3 | 74.1 | 73.6 | 70.6 | ||||
| Age at menarche (%), y | ||||||||
| <11 | 19.7 | 19.1 | 19.8 | 20.1 | ||||
| 12-13 | 53.9 | 56.0 | 54.7 | 53.7 | ||||
| 14-15 | 21.6 | 20.8 | 21.5 | 21.5 | ||||
| ≥16 | 4.7 | 4.1 | 4.0 | 4.7 | ||||
| Age at first birth (%), y | ||||||||
| <19 | 18.7 | 15.0 | 14.8 | 15.9 | ||||
| 20-24 | 46.9 | 49.1 | 47.7 | 47.5 | ||||
| 25-29 | 19.8 | 20.6 | 21.0 | 20.0 | ||||
| ≥30 | 6.0 | 6.4 | 7.3 | 7.4 | ||||
| Parity (%) | ||||||||
| 0 | 8.6 | 8.9 | 9.2 | 9.3 | ||||
| 1 | 7.0 | 6.6 | 7.2 | 7.4 | ||||
| 2 | 24.6 | 24.0 | 23.9 | 22.1 | ||||
| 3 | 26.2 | 25.7 | 25.0 | 24.6 | ||||
| 4 | 16.3 | 16.9 | 16.8 | 17.4 | ||||
| ≥5 | 17.3 | 17.9 | 17.9 | 19.2 | ||||
| Age at menopause (%), y | ||||||||
| <40 | 15.5 | 13.3 | 13.0 | 12.8 | ||||
| 40-44 | 13.9 | 14.6 | 15.5 | 13.2 | ||||
| 45-49 | 24.0 | 23.2 | 22.2 | 23.9 | ||||
| 50-54 | 36.6 | 37.6 | 39.3 | 38.2 | ||||
| ≥55 | 10.0 | 11.3 | 12.0 | 11.9 | ||||
| Menopausal hormone therapy (%) | ||||||||
| Current user | 52.0 | 53.1 | 52.6 | 49.6 | ||||
| Past user | 15.9 | 15.4 | 16.3 | 16.4 | ||||
| Dietary fat (g/d)*,‡ | 49.1 ± 10.3 | 54.1 ± 10.6 | 54.8 ± 10.6 | 51.3 ± 11.1 | ||||
| Alcohol (g/d)*,‡ | 4.91 ± 7.99 | 6.30 ± 10.46 | 7.11 ± 12.14 | 7.42 ± 14.81 | ||||