Table 2.
Distribution of cases and controls of pre-menopausal women
| Factor | Pre-menopausal women |
||||
|---|---|---|---|---|---|
| No. (%)a) |
p-valueb) | Unadjusted OR (95% CI)c) | Adjusted OR (95% CI)d) | ||
| Case (n=121, 27.2%) | Control (n=324, 72.8%) | ||||
| Age | |||||
| Mean±SD (yr) | 43.3±7.2 | 43.1±6.8 | 0.72 | ||
| Breast density (%) | |||||
| ≤ 75 | 67 (55.4) | 212 (65.4) | 0.04 | 1.0 (reference) | 1.0 (reference) |
| > 75 | 54 (44.6) | 112 (34.6) | 1.6 (1.1-2.3)* | 1.2 (0.6-2.2) | |
| Height (cm) | |||||
| Mean±SD | 154.7±5.4 | 154.6±5.6 | 0.95 | ||
| < 155 | 56 (46.3) | 151 (46.6) | 0.95 | 1.0 (reference) | |
| ≥ 155 | 65 (53.7) | 173 (53.4) | 1.0 (0.7-1.5) | ||
| Weight (kg) | |||||
| Mean±SD | 54.2±8.2 | 54.0±7.9 | 0.80 | ||
| ≤ 54 | 69 (57) | 180 (55.6) | 0.78 | 1.0 (reference) | |
| > 54 | 52 (43) | 144 (44.4) | 0.9 (0.6-1.4) | ||
| BMI | |||||
| Mean±SD | 22.6±3.0 | 22.5±3.0 | 0.83 | ||
| < 23 | 70 (57.5) | 199 (61.4) | 0.46 | 1.0 (reference) | |
| ≥ 23 | 51 (42.5) | 125 (38.6) | 1.2 (0.8-1.8) | ||
| Age at first menstrual period (yr) | |||||
| Mean±SD | 15.1±1.8 | 15.5±1.9 | 0.06 | ||
| < 14 | 27 (22.7) | 32 (10.1) | 0.001 | 2.6 (1.5-4.5)* | 2.3 (1.2-4.6)* |
| ≥ 14 | 89 (77.3) | 285 (89.9) | 1.0 (reference) | 1.0 (reference) | |
| Age at first birth (yr) | |||||
| Mean±SD | 23.8±3.8 | 23.6±4.3 | 0.80 | ||
| < 23 | 49 (39.1) | 151 (46.7) | 0.32 | 1.0 (reference) | |
| 23-29 | 63 (50) | 147 (45.4) | 1.3 (0.8-2.1) | ||
| ≥ 30 | 14 (10.9) | 26 (7.9) | 1.6 (0.7-3.5) | ||
| Age at last birth (yr) | |||||
| Mean±SD | 29.5±5.2 | 29.4±5.3 | 0.90 | ||
| < 30 | 64 (50.5) | 173 (53.3) | 0.61 | 1.0 (reference) | |
| ≥ 30 | 62 (49.5) | 151 (46.7) | 1.1 (0.7-1.7) | ||
| No. of pregnancies | |||||
| Mean±SD | 2.9±1.8 | 3.4±1.8 | 0.005 | ||
| < 3 | 64 (51.2) | 103 (31.8) | < 0.001 | 2.3 (1.5-3.6)* | 2.6 (1.6-4.4)* |
| ≥ 3 | 62 (48.8) | 221 (68.2) | 1.0 (reference) | 1.0 (reference) | |
| No. of babies born | |||||
| Mean±SD | 2.0±1.0 | 2.1±0.9 | 0.12 | ||
| < 2 | 30 (24) | 62 (19.1) | 0.26 | 1.3 (0.8-2.2) | |
| ≥ 2 | 96 (76) | 262 (80.9) | 1.0 (reference) | ||
| No. of months of breast feeding | |||||
| Mean±SD | 15.9±6.0 | 15.4±6.2 | 0.48 | ||
| < 15 | 52 (41.3) | 135 (41.8) | 0.93 | 1.0 (0.6-1.5) | |
| ≥ 15 | 74 (58.7) | 189 (58.2) | 1.0 (reference) | ||
| Hormone use | |||||
| No | 75 (62.2) | 244 (75.2) | 0.02 | 1.0 (reference) | 1.0 (reference) |
| Yes | 46 (37.8) | 80 (24.8) | 1.8 (1.1-3.0)* | 2.3 (1.3-3.9)* | |
| Family history of breast cancer | |||||
| No | 112 (92.5) | 304 (93.8) | 0.22 | 1.0 (reference) | |
| 1st degree | 3 (2.5) | 13 (4) | 0.6 (0.2-2.3) | ||
| 2nd degree | 6 (5) | 7 (2.2) | 2.3 (0.8-7.1) | ||
| Smoking | |||||
| No | 120 (99.2) | 317 (97.8) | 0.35 | 1.0 (reference) | |
| Yes | 1 (0.8) | 7 (2.2) | 0.4 (0.05-3.1) | ||
| Alcohol drinking | |||||
| No | 121 (100) | 323 (99.7) | 0.54 | 1.0 (reference) | |
| Yes | 0 (0) | 1 (0.3) | 0.7 (0.7-0.8) | ||
| Soy drinking | |||||
| < 1 Cup per day | 106 (87.6) | 283 (87.3) | 0.99 | 1.0 (reference) | |
| ≥ 1 Cup per day | 15 (12.4) | 41 (12.7) | 1.0 (0.5-2.0) | ||
| Coffee drinking | |||||
| < 1 Cup per day | 98 (81.1) | 285 (87.9) | 0.11 | 1.0 (reference) | |
| ≥ 1 Cup per day | 23 (18.9) | 39 (12.1) | 1.7 (0.9-3.2) | ||
| Vegetable consumption (servings) | |||||
| ≤ 1 | 15 (12.8) | 26 (8) | 0.38 | 1.0 (reference) | |
| 2-3 | 69 (57.4) | 191 (59) | 0.6 (0.3-1.3) | ||
| ≥ 4 | 37 (29.8) | 107 (33) | 0.6 (0.2-1.3) | ||
| Physical activities | |||||
| No (inactive) | 15 (12.4) | 20 (6.2) | 0.04 | 2.2 (1.0-4.9)* | 2.6 (0.8-8.0) |
| Yes (insufficient and sufficient) | 106 (87.6) | 304 (93.8) | 1.0 (reference) | 1.0 (reference) | |
OR, odds ratio; CI, confidence interval; SD, standard deviation; BMI, body mass index.
*
Statistically significant (p < 0.05).
a)
Number of participants (%),
b)
Obtained from t test for continuous variables and chi-squared test for categorical variables,
c)
Unadjusted OR (95% CI)—obtained from binary logistic regression,
d)
Multivariable adjusted OR (95% CI)—obtained from multiple logistic regression.