Table 2.
C-reactive protein levels by coffee consumption by study.
| Study Name | Gender | Categories in the Original Study: Median or Mid-Point Volume (mL) | P-Trend * | ||||
|---|---|---|---|---|---|---|---|
| None | Low | Medium | High | Very High | |||
| Number of Participants | |||||||
| Geometric Mean c-Reactive Protein (95% Confidence Intervals) (mg/L) | |||||||
| DREW trial [26] | None: 0 mL | 1 cup/month to 6 cups/week: 104 mL | 1 cup/day to 13 cups/week: 339 mL | ≥2 cups/day: 533 mL | — | ||
| Women | 104 | 86 | 89 | 65 | — | 0.05 | |
| 4.1 (3.4, 4.9) | 4.1 (3.3, 5.0) | 3.1 (2.6, 3.8) | 3 (2.4, 3.8) | — | |||
| None: 0 mL | <1 cup/day: 119 mL | 2–3 cups/day: 356 mL | ≥4 cups/day: 1037 mL | — | |||
| NHS [18] | Women | 3433 | 4178 | 5653 | 2287 | — | 0.02 |
| 4.18 (3.55, 4.92) | 4.04 (3.60, 4.52) | 3.25 (3.03, 3.48) | 2.37 (2.16, 2.59) | — | |||
| HPFS [18] | Men | 1723 | 2341 | 2354 | 979 | — | 0.37 |
| 1.09 (0.92, 1.29) | 1.07 (0.95, 1.21) | 0.97 (0.88, 1.06) | 1.00 (0.88, 1.12) | — | |||
| EPIC study [22] | None: 0 mL | Low: 103 mL | Medium–low: 297 mL | Medium–high: 451 mL | High: 745 mL | ||
| Men | 212 | 1078 | 977 | 1078 | 935 | 0.01 | |
| 1.15 (1.13, 1.16) | 1.16 (1.15, 1.18) | 1.18 (1.17, 1.20) | 1.21 (1.19, 1.22) | 1.34 (1.33, 1.36) | |||
| Women | 832 | 2730 | 2171 | 2730 | 2057 | 0.002 | |
| 1.42 (1.40, 1.45) | 1.39 (1.36, 1.41) | 1.28 (1.26, 1.30) | 1.26 (1.24, 1.30) | 1.16 (1.14, 1.17) | |||
| Kyushu University Cohort Study [25] | None: 0 mL | <1 cup/day: 75 mL | 1–3 cups/day: 300 mL | 4–6 cups/day: 750 mL | ≥7 cups/day: 1305 mL | ||
| Men | 721 | 1145 | 1986 | 469 | 86 | 0.03 | |
| 0.55 (0.51, 0.59) | 0.53 (0.50, 0.56) | 0.51 (0.49, 0.53) | 0.5 (0.46, 0.55) | 0.44 (0.35, 0.55) | |||
| Women | 892 | 1578 | 2944 | 444 | 60 | 0.50 | |
| 0.40 (0.38, 0.43) | 0.40 (0.38, 0.42) | 0.39 (0.38, 0.41) | 0.41 (0.37, 0.45) | 0.31 (0.24, 0.39) | |||
| ATTICA study [17] | None: 0 mL | <200 mL/day: 100 mL | 200–400 mL/day: 300 mL | >400 mL/day: 650 mL | — | ||
| Men | 133 | 758 | 521 | 27 | — | 0.11 | |
| 2.3 (0.76, 3.84) | 2.2 (0.76, 3.64) | 2.9 (−0.56, 6.36) | 3.1 (1.85, 4.35) | — | |||
| Women | 366 | 922 | 211 | 19 | — | 0.21 | |
| 2.1 (0.66, 3.54) | 2.0 (0.56, 3.44) | 2.7 (−0.76, 6.16) | 2.9 (1.36, 4.44) | — | |||
| Singapore Prospective Study [19] | Never/rarely: 0 mL | <1 cup/day: 123 mL | 1–2 cups/day: 323 mL | ≥3 cups/day: 860 mL | — | ||
| Both | 1202 | 475 | 2118 | 344 | — | 0.37 | |
| 1.31 (1.16, 1.49) | 1.43 (1.25, 1.65) | 1.28 (1.14, 1.44) | 1.23 (1.05, 1.44) | — | |||
| Aichi Workers’ Cohort Study [20] | <1 cup: 75 mL | 1 cup: 150 mL | 2–3 cups: 375 mL | ≥4 cups/day: 750 mL | — | ||
| Both | 949 | 803 | 1336 | 229 | — | 0.51 | |
| 0.43 (0.41, 0.47) | 0.4 (0.37, 0.43) | 0.37 (0.35, 0.40) | 0.42 (0.36, 0.48) | — | |||
| United Kingdom study [21] | — | <1 cup/day: 45 mL | 1–2 cups/day: 195 mL | >2 cups/day: 435 mL | — | ||
| Men | — | 16 | 20 | 41 | — | 0.94 | |
| — | 0.97 (0.77, 1.17) | 0.83 (0.64, 1.02) | 0.94 (0.82, 1.06) | — | |||
| FinnDiane Study [23] | <1 cup/day: 75 mL | ≥ 1 cup/day < 3: 300 mL | ≥ 3 cups/day < 5: 600 mL | ≥5 cups/day: 1013 mL | — | ||
| Both | 134 | 230 | 371 | 305 | — | 0.27 | |
| 1.93 (1.56, 2.30) | 1.88 (1.61, 2.16) | 1.62 (1.41, 1.82) | 1.68 (1.44, 1.91) | — | |||
| BELSTRESS [24] | None | 1–3 cups/day: 300 mL | >3cups/day: 750 mL | — | — | ||
| Men | 168 | 415 | 448 | — | — | 0.30 | |
| 0.89 (0.75, 1.04) | 0.95 (0.81, 1.11) | 0.97 (0.82, 1.14) | — | — | |||
* P-trend was re-calculated based on the estimated mid-point volume (in mL) of coffee consumption in each category and obtained by treating coffee volume as continuous in a model testing a linear association between coffee consumption and CRP level.