Table 3.
The relation for genetic risk score and established conventional risk factors with risk of breast cancer, The Singapore Chinese Health Study, 1993 to 1998
| Variable | Case (n = 411), n (%) | Control (n = 1,212), n (%) | OR (95% CI) | P value | Adjusted OR (95% CI) ᶲ | P value | Adjusted OR (95% CI) ‡ | P value |
|---|---|---|---|---|---|---|---|---|
| Genetic risk score, quartiles (range), mean |
|
|
|
|
|
|
|
|
| First (32.4-43.6), 40.4 |
80 (19.5) |
326 (26.9) |
1.00 (ref) |
|
1.00 (ref) |
|
1.00 (ref) |
|
| Second (43.6-47.1), 45.4 |
96 (23.4) |
310 (25.6) |
1.26 (0.90, 1.75) |
0.178 |
1.25 (0.90, 1.75) |
0.182 |
1.26 (0.90, 1.76) |
0.174 |
| Third (47.1-50.6), 48.9 |
109 (26.5) |
296 (24.4) |
1,47 (1.06, 2.04) |
0.020 |
1.49 (1.07, 2.06) |
0.017 |
1.47 (1.06, 2.04) |
0.022 |
| Fourth (50.6-65.8), 53.6 |
126 (30.7) |
280 (23.1) |
1.78 (1.29, 2.44) |
<0.001 |
1.74 (1.26, 2.40) |
0.001 |
1.75 (1.27, 2.41) |
0.001 |
|
P trend |
|
|
1.21 (1.09, 1.33) |
<0.001 |
1.20 (1.09, 1.33) |
<0.001 |
1.20 (1.08, 1.33) |
<0.001 |
| Age at first live birth, years |
|
|
|
|
|
|
|
|
| <20 |
56 (13.6) |
212 (17.5) |
1.00 (ref) |
|
1.00 (ref) |
|
1.00 (ref) |
|
| 20-24 |
129 (31.4) |
458 (37.8) |
1.11 (0.77, 1.59) |
0.571 |
1.04 (0.72, 1.50) |
0.823 |
1.05 (0.73, 1.51) |
0.804 |
| 25-29 or null |
175 (42.6) |
416 (34.3) |
1.67 (1.16, 2.39) |
0.005 |
1.51 (1.04, 2.18) |
0.030 |
1.49 (1.03, 2.15) |
0.036 |
| ≥30 |
51 (12.4) |
126 (10.4) |
1.62 (1.03, 2.55) |
0.038 |
1.46 (0.92, 2.31) |
0.111 |
1.49 (1.03, 2.29) |
0.131 |
|
P trend |
|
|
1.25 (1.09, 1.42) |
0.001 |
1.20 (1.05, 1.38) |
0.008 |
1.19 (1.04, 1.37) |
0.011 |
| Age at menarche, years |
|
|
|
|
|
|
|
|
| ≥14 |
160 (38.9) |
540 (44.6) |
1.00 (ref) |
|
1.00 (ref) |
|
1.00 (ref) |
|
| 12-13 |
180 (43.8) |
484 (39.9) |
1.29 (1.00, 1.66) |
0.049 |
1.21 (0.93, 1.56) |
0.151 |
1.23 (0.94, 1.60) |
0.126 |
| <12 |
71 (17.3) |
188 (15.5) |
1.34 (0.95, 1.89) |
0.097 |
1.20 (0.84, 1.71) |
0.312 |
1.19 (0.83, 1.71) |
0.345 |
|
P trend |
|
|
1.18 (1.00, 1.39) |
0.048 |
1.12 (0.94, 1.32) |
0.208 |
1.11 (0.94, 1.33) |
0.220 |
| Family history |
|
|
|
|
|
|
|
|
| No |
400 (97.3) |
1196 (98.7) |
1.00 (ref) |
|
1.00 (ref) |
|
1.00 (ref) |
|
| Yes |
11 (2.7) |
16 (1.3) |
2.11 (0.97, 4.61) |
0.061 |
2.06 (0.94, 4.52) |
0.071 |
1.78 (0.79, 4.00) |
0.162 |
| Past breast biopsy, n (%) |
|
|
|
|
|
|
|
|
| No |
401 (97.6) |
1193 (98.4) |
1.00 (ref) |
|
1.00 (ref) |
|
1.00 (ref) |
|
| Yes |
10 (2.4) |
19 (1.6) |
1.55 (0.69, 3.48) |
0.288 |
1.36 (0.60, 3.08) |
0.462 |
1.36 (0.58, 3.20) |
0.475 |
| Body mass index, kg/m2 |
|
|
|
|
|
|
|
|
| <20 |
51 (12.4) |
167 (13.8) |
1.00 (ref) |
|
1.00 (ref) |
|
1.00 (ref) |
|
| 20 to <24 |
216 (52.6) |
659 (54.4) |
1.09 (0.77, 1.54) |
0.632 |
1.11 (0.78, 1.58) |
0.562 |
1.16 (0.81, 1.66) |
0.423 |
| 24 to <28 |
102 (24.8) |
305 (25.2) |
1.10 (0.75, 1.62) |
0.610 |
1.12 (0.76, 1.64) |
0.558 |
1.15 (0.78, 1.70) |
0.488 |
| 28 or higher |
42 (10.2) |
81 (6.7) |
1.74 (1.07, 2.85) |
0.027 |
1.83 (1.12, 3.01) |
0.016 |
1.99 (1.21, 3.29) |
0.007 |
| P trend | 1.14 (0.99, 1.31) | 0.067 | 1.15 (1.00, 1.33) | 0.048 | 1.17 (1.02, 1.35) | 0.031 |
ᶲAdjusted for education; ‡adjusted for education and all other factors in the table. OR, odds ratio; CI, confidence interval.