Table 3.
Distribution of number of cups of coffee products and its association with breast cancer riska.
| Cups of coffee drinking per day, n (%) | Controls (N = 1 013) | Cases (N = 1 156) | Crude OR (95% CI)bc | Adjusted OR (95% CI)bcd |
|---|---|---|---|---|
| Overall coffee | ||||
| Non-habitual coffee drinker | 834 (82.3) | 918 (79.4) | 1.00 | 1.00 |
| <1 cup/day | 51 (5.0) | 77 (6.7) | 1.37 (0.95–1.98) | 1.22 (0.80–1.85) |
| ≥1 cup/day | 128 (12.6) | 161 (13.9) | 1.14 (0.89–1.47) | 1.09 (0.81–1.46) |
| Instant coffee | ||||
| Non-habitual coffee drinker | 900 (88.8) | 974 (84.3) | 1.00 | 1.00 |
| <1 cup/day | 37 (3.7) | 63 (5.4) | 1.55 (1.02–2.35) | 1.36 (0.85–2.17) |
| ≥1 cup/day | 76 (7.5) | 119 (10.3) | 1.42 (1.05–1.93) | 1.45 (1.02–2.06) |
| Two/Three in one | ||||
| Non-habitual coffee drinker | 998 (98.5) | 1 119 (96.8) | 1.00 | 1.00 |
| <1 cup/day | 4 (0.4) | 10 (0.9) | 2.27 (0.71–7.27) | 2.91 (0.61–13.91) |
| ≥1 cup/day | 11(1.1) | 27 (2.3) | 2.23 (1.10–4.52) | 2.51 (1.14–5.57) |
| Brewed coffee | ||||
| Non-habitual coffee drinker | 954 (94.2) | 1 112 (96.3) | 1.00 | 1.00 |
| <1 cup/day | 24 (2.4) | 25 (2.2) | 0.95 (0.54–1.67) | 0.67 (0.35–1.29) |
| ≥1 cup/day | 35 (3.5) | 18 (1.6) | 0.47 (0.26–0.83) | 0.40 (0.20–0.76) |
| Homemade coffee | ||||
| Non-habitual coffee drinker | 889 (97.7) | 902 (97.5) | 1.00 | 1.00 |
| <1 cup/day | 10 (1.0) | 13 (1.1) | 1.18 (0.52–2.71) | 0.93 (0.37–2.33) |
| ≥1 cup/day | 15 (1.5) | 13 (1.1) | 0.79 (0.37–1.66) | 0.65 (0.27–1.60) |
| Restaurant coffee | ||||
| Non-habitual coffee drinker | 977 (96.4) | 1 139 (98.5) | 1.00 | 1.00 |
| <1 cup/day | 17 (1.7) | 12 (1.0) | 0.64 (0.30–1.35) | 0.44 (0.19–1.03) |
| ≥1 cup/day | 19 (1.9) | 5 (0.4) | 0.24 (0.09–0.64) | 0.23 (0.08–0.65) |
| Others e | ||||
| Non-habitual coffee drinker | 897 (98.2) | 898 (97.4) | 1.00 | 1.00 |
| <1 cup/day | 6 (0.6) | 12 (1.0) | 1.82 (0.68–4.86) | 2.30 (0.69–7.64) |
| ≥1 cup/day | 13 (1.3) | 14 (1.2) | 0.98 (0.46–2.09) | 0.80 (0.35–1.80) |
aParticipants with missing values were excluded from the analysis.
bThe reference group was defined as the participants who did not have a habitual coffee consumption (i.e., coffee drinking vs. non-coffee drinking; instant coffee drinking vs. non- coffee drinking).
cParticipants who drank both instant coffee and brewed coffee were excluded in the logistic regression models.
dAdjusted for age at interview, educational attainment, family breast cancer history, previous history of benign breast diseases, body mass index (BMI), shift work experiences, smoking status, alcohol and tea drinking consumption, and deep fried food and green vegetable consumption. eOther coffee referred to those who drank decaffeinated coffee or had no preferable coffee products.