Table 1.
Age standardized distribution of potential risk factors for breast cancer according to fifths of total red meat intake in 1991 among women enrolled in the Nurses’ Health Study II
| Potential risk factors | Total red meat intake fifth | ||||
|---|---|---|---|---|---|
| Lowest fifth (n=15 763) | 2nd fifth (n=21 366) | 3rd fifth (n=15 929) | 4th fifth (n=18 196) | Highest fifth (n=17 549) | |
| Mean (SD) age (years) | 36.6 (4.7) | 36.5 (4.6) | 36.5 (4.6) | 36.4 (4.6) | 36.2 (4.6) |
| Mean (SD) total red meat intake (serving/day) | 0.2 (0.1) | 0.5 (0.1) | 0.7 (0.1) | 1.0 (0.1) | 1.6 (0.5) |
| Mean (SD) body mass index (weight (kg)/(height (m)2) | 23.3 (4.4) | 24.2 (4.8) | 24.5 (5.1) | 24.9 (5.4) | 25.7 (6.0) |
| Mean (SD) total energy intake (kJ) | 6266 (2057) | 6688 (1960) | 7265 (1977) | 7963 (1998) | 9271 (2186) |
| Mean (SD) alcohol consumption (g/day) | 3.2 (5.7) | 3.2 (6.0) | 3.1 (6.1) | 3.1 (6.1) | 3.0 (6.4) |
| Mean (SD) age at first birth (years) | 26.4 (4.6) | 26.1 (4.2) | 25.9 (4.1) | 25.7 (4.0) | 25.4 (4.0) |
| Current smokers (%) | 9 | 11 | 12 | 13 | 15 |
| Current oral contraceptive use (%) | 12 | 12 | 11 | 10 | 10 |
| History of benign breast disease (%) | 35 | 33 | 34 | 32 | 31 |
| Family history of breast cancer in mother or sisters (%) | 16 | 15 | 15 | 15 | 15 |
| Parity ≥3 (%) | 12 | 19 | 22 | 24 | 26 |
| Age at menarche <12 (%) | 25 | 24 | 24 | 24 | 25 |