TABLE 2.
Intakes of coffee, tea, and alcohol in relation to risk of diabetes in the Black Women's Health Study, 1995–20071
| Cases | Person-years | RR (95% CI)2 | RR (95% CI)3 | |
| Caffeinated coffee | ||||
| No coffee | 1278 | 167,264 | 1.00 (Ref) | 1.00 (Ref) |
| 1 cup/mo to <1 cup/d | 903 | 112,148 | 0.97 (0.89, 1.06) | 0.94 (0.86, 1.04) |
| 1 cup/d | 444 | 51,261 | 0.92 (0.82, 1.02) | 0.90 (0.81, 1.01) |
| 2–3 cups/d | 311 | 38,817 | 0.82 (0.72, 0.93) | 0.82 (0.72, 0.93) |
| ≥4 cups/d | 119 | 12,704 | 0.88 (0.72, 1.06) | 0.83 (0.69, 1.01) |
| P for trend | 0.009 | 0.003 | ||
| Decaffeinated coffee | ||||
| No coffee | 1278 | 167,264 | 1.00 (Ref) | 1.00 (Ref) |
| 1 cup/mo to <1 cup/d | 735 | 84,704 | 0.96 (0.87, 1.05) | 1.04 (0.93, 1.16) |
| 1 cup/d | 206 | 18,772 | 1.03 (0.89, 1.20) | 1.07 (0.92, 1.25) |
| 2–3 cups/d | 109 | 10,097 | 0.95 (0.78, 1.16) | 1.01 (0.83, 1.24) |
| ≥4 cups/d | 46 | 3363 | 1.09 (0.81, 1.47) | 1.10 (0.81, 1.49) |
| P for trend | 0.65 | 0.58 | ||
| Tea | ||||
| None to <1 cup/mo | 945 | 112,638 | 1.00 (Ref) | 1.00 (Ref) |
| 1 cup/mo to <1 cup/d | 2063 | 252,073 | 1.03 (0.95, 1.11) | 1.04 (0.96, 1.13) |
| 1 cup/d | 334 | 40,816 | 0.95 (0.84, 1.08) | 0.99 (0.87, 1.12) |
| 2–3 cups/d | 234 | 24,284 | 1.10 (0.95, 1.27) | 1.12 (0.97, 1.30) |
| ≥4 cups/d | 95 | 9236 | 1.06 (0.86, 1.31) | 1.14 (0.92, 1.42) |
| P for trend | 0.49 | 0.17 | ||
| Alcohol | ||||
| Never | 1669 | 208,356 | 1.00 (Ref) | 1.00 (Ref) |
| Former | 1159 | 104,764 | 1.22 (1.13, 1.31) | 1.07 (0.99, 1.16) |
| 1–3 drinks/wk | 552 | 77,309 | 0.84 (0.76, 0.93) | 0.90 (0.82, 1.00) |
| 4–6 drinks/wk | 132 | 25,071 | 0.60 (0.51, 0.72) | 0.68 (0.57, 0.81) |
| 7–13 drinks/wk | 97 | 14,885 | 0.70 (0.57, 0.86) | 0.78 (0.63, 0.96) |
| ≥14 drinks/wk | 43 | 6565 | 0.71 (0.52, 0.96) | 0.72 (0.53, 0.98) |
| P for trend4 | <0.0001 | <0.0001 |
1
RR, relative risk (estimated by using Cox proportional hazards models); Ref, referent.
2
Adjusted for age, questionnaire cycle, and energy intake.
3
Adjusted for age, questionnaire cycle, energy intake, education, family history of diabetes, vigorous activity, smoking, glycemic index, cereal fiber, sugar-sweetened soft drinks, BMI, history of hypertension, and history of high cholesterol. Caffeinated coffee, decaffeinated coffee, tea, and alcohol were included in the same model.
4
Test for trend excluded former drinkers.