TABLE 4.
Summary and comparison of individual meta-analysis articles, our umbrella review, and the WCRF report on associations of tea and cancer1
| Meta-analyses from original articles | Umbrella review | WCRF | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cancer type | Tea type | No. of meta-analyses | D/N/I | Evidence C/S/W/N/X | Comparison | No. of studies | D/N/I | RR (95% CI) | Level of evidence2 | Level of evidence |
| Biliary tract | Any | 1 | 1/0/0 | 0/1/0/0/0 | Any vs. none | 8 | 4/4/0 | 0.77 (0.64, 0.92) | Suggestive | N/A |
| Brain cancer | Any | 1 | 0/1/0 | 0/0/0/1/0 | Any vs. none | 8 | 2/6/0 | 0.89 (0.76, 1.05) | Nonsignificant | N/A |
| Breast | Any | 3 | 1/2/0 | 0/0/1/2/0 | Any vs. none | 26 | 6/20/0 | 0.81 (0.71, 0.94) | Weak | Limited—no conclusion |
| High vs. low | 23 | 1/20/2 | 0.98 (0.90, 1.06) | Nonsignificant | ||||||
| Black | 9 | 0/8/1 | 0/0/1/8/0 | High vs. low | 28 | 1/27/0 | 0.98 (0.91, 1.06) | Nonsignificant | ||
| High vs. low (cohort) | 15 | 0/15/0 | 1.04 (0.97, 1.12) | Nonsignificant | ||||||
| High vs. low (CC) | 13 | 1/12/0 | 0.91 (0.80, 1.03) | Nonsignificant | ||||||
| Green | 15 | 7/8/0 | 0/3/3/8/1 | High vs. low (CC) | 11 | 6/5/0 | 0.75 (0.61, 0.92) | Suggestive | ||
| High vs. low | 16 | 6/10/0 | 0.82 (0.71, 0.96) | Weak | ||||||
| High vs. low (cohort) | 5 | 0/5/0 | 0.99 (0.83, 1.77) | Nonsignificant | ||||||
| Any vs. none (CC) | 5 | 3/2/0 | 0.94 (0.83, 1.05) | Nonsignificant | ||||||
| Any vs. none | 14 | 3/11/0 | 0.87 (0.76, 0.99) | Weak | ||||||
| Any vs. none (cohort) | 9 | 0/9/0 | 0.83 (0.62, 1.10) | Nonsignificant | ||||||
| Bladder | Any | 5 | 0/5/0 | 0/0/0/5/0 | High vs. low (CC) | 25 | 1/22/2 | 0.97 (0.87, 1.09) | Nonsignificant | Limited—suggestive: decreases risk RR = 0.94 (95% CI: 0.89, 0.98) |
| High vs. low (cohort) | 8 | 1/7/0 | 0.86 (0.65, 1.13) | Nonsignificant | ||||||
| High vs. low | 33 | 2/29/2 | 0.95 (0.86, 1.06) | Nonsignificant | ||||||
| Green | 2 | 1/1/0 | 0/1/0/1/0 | High vs. low | 5 | 0/5/0 | 1.03 (0.82, 1.31) | Nonsignificant | ||
| Colorectal | Any | 4 | 1/3/0 | 0/0/1/3/0 | High vs. low | 53 | 6/45/2 | 0.93 (0.87, 0.99) | Weak | Limited—no conclusion |
| Black | 1 | 0/1/0 | 0/0/0/1/0 | High vs. low | 20 | 2/14/4 | 0.99 (0.87, 1.13) | Nonsignificant | ||
| Green | 3 | 1/2/0 | 0/0/1/2/0 | High vs. low | 15 | 4/11/0 | 0.87 (0.75, 1.00)3 | Weak | ||
| Colon | Green | 1 | 0/1/0 | 0/0/0/1/0 | High vs. low | 11 | 1/9/1 | 0.98 (0.85, 1.12) | Nonsignificant | Limited—no conclusion |
| Rectal | Green | 1 | 0/1/0 | 0/0/0/1/0 | High vs. low | 3/6/0 | 0.97 (0.77, 1.22) | Nonsignificant | Limited—no conclusion | |
| Endometrial | Any | 5 | 3/2/0 | 0/3/0/2/0 | High vs. low | 16 | 3/12/1 | 0.90 (0.75, 1.09) | Nonsignificant | Limited—no conclusion |
| Increment of 1 cup/d | 5 | 0/4/1 | 1.04 (0.98, 1.10) | Nonsignificant | ||||||
| Black | 3 | 0/3/0 | 0/0/0/3/0 | High vs. low | 6 | 2/4/0 | 0.78 (0.61, 1.00)3 | Suggestive | ||
| Green | 3 | 3/0/0 | 0/3/0/0/0 | High vs. low | 10 | 1/8/1 | 0.99 (0.79, 1.23) | Nonsignificant | ||
| Esophageal | Green | 6 | 1/5/0 | 0/0/1/5/0 | High vs. low | 22 | 9/11/2 | 0.81 (0.62, 1.06) | Nonsignificant | N/A |
| Gastric | Any | 2 | 1/1/0 | 0/0/1/1/0 | Any vs. none | 56 | 23/30/3 | 0.78 (0.70, 0.86) | Weak | Limited—no conclusion |
| Increment of 3 cup/d | 5 | 0/5/0 | 0.98 (0.89, 1.08) | Nonsignificant | ||||||
| Black | 1 | 0/1/0 | 0/0/0/1/0 | High vs. low | 5 | 0/4/1 | 1.18 (0.79, 1.77) | Nonsignificant | ||
| Green | 14 | 4/10/0 | 0/1/3/10/0 | High vs. low | 30 | 3/25/2 | 0.93 (0.84, 1.04) | Nonsignificant | ||
| Gallbladder | Any | 2 | 0/2/0 | 0/0/0/2/0 | High vs. low | 4 | 2/2/0 | 0.57 (0.25, 1.30) | Nonsignificant | Limited—no conclusion |
| Any vs. none | 6 | 3/3/0 | 0.67 (0.40, 1.12) | Nonsignificant | ||||||
| Glioma | Any | 2 | 1/1/0 | 0/0/1/1/0 | Any vs. none | 4 | 0/4/0 | 0.67 (0.40, 1.12) | Nonsignificant | N/A |
| High vs. low | 4 | 1/3/0 | 0.57 (0.25, 1.30) | Nonsignificant | ||||||
| Renal cell carcinoma | Any | 1 | 0/1/0 | 0/0/0/1/0 | Any vs. none | 12 | 1/11/0 | 1.03 (0.88, 1.21) | Nonsignificant | Limited—no conclusion |
| Liver | Any | 2 | 0/2/0 | 0/0/0/2/0 | Any vs. none | 12 | 3/9/0 | 0.77 (0.57, 1.03) | Nonsignificant | N/A |
| Green | 2 | 2/0/0 | 0/1/1/0/0 | High vs. low | 11 | 2/9/0 | 0.87 (0.78, 0.98) | Suggestive | ||
| Any vs. none | 10 | 3/7/0 | 0.65 (0.48, 0.88) | Weak | ||||||
| Lung | Any | 1 | 1/0/0 | 0/0/1/0/0 | Any vs. none | 44 | 18/24/2 | 0.76 (0.68, 0.86) | Weak | Limited—no conclusion |
| Black | 2 | 0/2/0 | 0/0/0/2/0 | High vs. low | 14 | 4/10/0 | 0.86 (0.70, 1.05) | Nonsignificant | ||
| Green | 2 | 1/1/0 | 0/0/1/1/0 | High vs. low | 12 | 4/7/1 | 0.78 (0.61, 1.01) | Nonsignificant | ||
| Leukemia (in childhood) | Any | 8 | 0/8/0 | 0/0/0/8/0 | High vs. low | 9 | 0/8/1 | 0.93 (0.74, 1.18) | Nonsignificant | N/A |
| Any vs. none | 14 | 0/14/0 | 0.93 (0.82, 1.05) | Nonsignificant | ||||||
| Leukemia | Any | 2 | 2/0/0 | 0/0/2/0/0 | High vs. low | 8 | 4/4/0 | 0.55 (0.43, 0.72) | Weak | N/A |
| Any vs. none | 8 | 1/7/0 | 0.76 (0.65, 0.89) | Weak | ||||||
| Ovarian | Any | 9 | 5/4/0 | 0/1/4/4/0 | Any vs. none | 21 | 8/22/1 | 0.82 (0.71, 0.94) | Weak | Limited—no conclusion |
| Black | 1 | 0/1/0 | 0/0/0/1/0 | Any vs. none | 16 | 4/12/0 | 0.90 (0.78, 1.04) | Nonsignificant | ||
| Green | 2 | 1/1/0 | 0/0/1/1/0 | Any vs. none | 9 | 3/5/1 | 0.76 (0.57, 1.02) | Nonsignificant | ||
| Laryngeal | Any | 5 | 0/5/0 | 0/0/0/4/1 | High vs. low | 8 | 2/5/1 | 0.91 (0.67, 1.23) | Nonsignificant | Limited—no conclusion |
| Oral | Any | 1 | 1/0/0 | 1/0/0/0/0 | Any vs. none | 6 | 6/0/0 | 0.62 (0.55, 0.72) | Convincing | Limited—no conclusion |
| Any | 5 | 2/2/0 | 0/2/0/2/0 | High vs. low | 31 | 5/26/0 | 0.86 (0.80, 0.91) | Suggestive | ||
| Green | 1 | 1/0/0 | 0/1/0/0/0 | High vs. low | 5 | 1/4/0 | 0.82 (0.69, 0.96) | Suggestive | ||
| Oropharyngeal | Any | 3 | 1/2/0 | 0/0/1/1/1 | Any vs. none | 6 | 2/4/0 | 0.68 (0.45, 1.03) | Nonsignificant | Limited—no conclusion |
| Pharyngeal | Any | 3 | 0/3/0 | 0/0/0/2/1 | Any vs. none | 4 | 0/4/0 | 0.88 (0.74, 1.04) | Nonsignificant | Limited—no conclusion |
| Pancreatic | Any | 4 | 0/4/0 | 0/0/0/4/0 | High vs. low | 22 | 1/20/1 | 0.97 (0.85, 1.10) | Nonsignificant | Limited—no conclusion |
| Any vs. none | 29 | 2/25/2 | 0.99 (0.89, 1.10) | Nonsignificant | ||||||
| Green | 1 | 0/1/0 | 0/0/0/1/0 | High vs. low | 8 | 1/6/1 | 0.99 (0.78, 1.25) | Nonsignificant | ||
| Prostate | Any | 1 | 0/1/0 | 0/0/0/1/0 | High vs. low | 23 | 6/15/2 | 0.86 (0.71, 1.04) | Nonsignificant | Limited—no conclusion |
| Any vs. none | 29 | 7/20/2 | 0.87 (0.75, 1.01) | Nonsignificant | ||||||
| Black | 2 | 0/2/0 | 0/0/0/2/0 | High vs. low | 11 | 1/9/1 | 0.99 (0.82, 1.20) | Nonsignificant | ||
| Green | 4 | 0/4/0 | 0/0/0/4/0 | High vs. low | 9 | 3/6/0 | 0.73 (0.51, 1.06) | Nonsignificant | ||
| Thyroid | Any | 1 | 1/0/0 | 0/0/1/0/0 | High vs. low | 14 | 1/13/0 | 0.77 (0.61, 0.97) | Weak | N/A |
| Skin (nonmelanoma) | Any | 1 | 0/1/0 | 0/0/0/1/0 | Any vs. none | 8 | 4/4/0 | 0.88 (0.76, 1.02) | Nonsignificant | N/A |
1
CC, case-control studies; C/S/W/N/D, convincing/suggestive/weak/nonsignificant/not adequately assessed; D/N/I, decrease in risk/no association/increase in risk; N/A, not applicable; WCRF, World Cancer Research Fund network.
2
The definition of each category of the level of evidence is presented in Supplemental Table 1.
3
The value is rounded up (to 2 decimal places), and hence is statistically significant.