Table 2.
Breast cancer incidence by baseline BMI and family history of cancer.
| Factors | No. of subjects | No. of cases | Person-years | CIR (95%CI) (1/100,000 person-years) | HR (95% CI)1 |
|---|---|---|---|---|---|
| BMI (China category, kg/m2) | |||||
| < 18.5 | 697 | 8 | 8026.07 | 99.68 (49.85, 199.31) | 1.05 (0.50, 2.21) |
| 18.5–23.9 | 5420 | 58 | 62,517.10 | 92.77 (71.72, 120.06) | 1 (reference) |
| 24–27.9 | 6255 | 78 | 72,472.83 | 107.63 (86.20, 134.37) | 1.24 (0.88, 1.75) |
| ≥ 28 | 2683 | 52 | 31,265.91 | 166.32 (126.73, 218.26) | 2.09 (1.42, 3.07) |
| Family history of cancer | |||||
| Yes | 4210 | 79 | 48,441.97 | 163.08 (130.81, 203.32) | 1.63 (1.22, 2.49) |
| No | 10,845 | 117 | 125,839.90 | 92.98 (77.57, 111.45) | 1 (reference) |
| Overall | 15,055 | 196 | 174,281.91 | 110.74 (96.19, 127.52) | |
*HR:Hazard ratio adjusted for age(< 60, ≥ 60);marriage status(in marriage ,not in marriage);education(primary, secondary, tertiary); personal monthly income (< 2000¥, 2000–4000¥, > 4000¥);smoking (yes, no);drinking (yes, no);daily fruit and vegetable intake (< 300, > 300 g/day); frequency of preserved food per week(at least once, not even once); frequency of fried and smoked food per week(at least once, not even once); frequency of high-fat food per week(at least once, not even once);family history of cancer (yes, no);diabetes(yes, no).