TABLE 1.
Summary risk estimates for the association between total nut intake and risk of cancer in adults aged ≥18 y1
| n 2 | Pooled ES (95% CI)3 | I 2 (%)4 | Q-statistic5 | |
|---|---|---|---|---|
| The highest vs. lowest comparison of total nut intake6 | ||||
| Overall cancer | 48 | 0.86 (0.81, 0.92)* | 58.1 | 112.0* |
| Study design | ||||
| Prospective | 33 | 0.90 (0.86, 0.94)* | 10.9 | 35.9 |
| Case-control | 15 | 0.77 (0.60, 0.97)* | 81.3 | 74.7* |
| Gender | ||||
| Male | 9 | 0.93 (0.82, 1.05) | 47.3 | 15.1 |
| Female | 16 | 0.91 (0.85, 0.98)* | 9.4 | 16.5 |
| Both | 23 | 0.86 (0.81, 0.92)* | 68.5 | 69.8* |
| Geographical region | ||||
| USA | 17 | 0.86 (0.79, 0.92)* | 47.9 | 30.6* |
| Non-USA countries | 31 | 0.87 (0.79, 0.96)* | 62.8 | 80.6* |
| Sample size, individuals | ||||
| <10,000 | 28 | 0.83 (0.73, 0.94)* | 71 | 93.2 |
| ≥10,000 | 20 | 0.89 (0.85, 0.92)* | 0 | 18.7 |
| Follow-up, year | ||||
| <15 | 9 | 0.84 (0.80, 0.99)* | 2.6 | 8.2 |
| ≥15 | 24 | 0.90 (0.85, 0.94)* | 16.9 | 27.6 |
| Nut intake assessment | ||||
| Only FFQ | 45 | 0.86 (0.80, 0.92)* | 60.0 | 109.8* |
| FFQ and dietary recall | 3 | 0.94 (0.81, 1.09) | 0 | 1.6 |
| Cancer assessment | ||||
| Medical records | 33 | 0.87 (0.81, 0.93)* | 57.2 | 74.8* |
| Pathological or histological | 15 | 0.85 (0.71, 1.02) | 61.9 | 36.7* |
| Adjustment for energy | ||||
| Yes | 41 | 0.86 (0.81, 0.92)* | 56.9 | 92.1* |
| No | 7 | 0.92 (0.68, 1.24) | 68.6 | 19.1* |
| Adjustment for BMI | ||||
| Yes | 39 | 0.86 (0.81, 0.92)* | 58.4 | 91.4* |
| No | 9 | 0.90 (0.67, 1.23) | 60.3 | 20.1* |
| Effect size type | ||||
| HR | 28 | 0.89 (0.85, 0.94)* | 18.5 | 33.1 |
| RR | 7 | 0.92 (0.73, 1.16) | 60.1 | 15.0* |
| OR | 13 | 0.73 (0.57, 0.92)* | 79.9 | 59.6* |
| Specific cancers | ||||
| Prostate | 6 | 0.96 (0.85, 1.10) | 43.2 | 8.8 |
| Colorectal | 3 | 0.64 (0.39, 1.05) | 92 | 24.8* |
| Colon | 5 | 0.61 (0.43, 0.85)* | 75.9 | 16.6* |
| Rectal | 3 | 0.68 (0.34, 1.37) | 89.2 | 18.5* |
| Lung | 5 | 0.85 (0.81, 0.90)* | 0 | 1.7 |
| Esophageal | 5 | 0.84 (0.65, 1.09) | 51 | 8.1 |
| Gastric | 7 | 0.88 (0.68, 1.13) | 64.6 | 16.9* |
| Pancreatic | 5 | 0.83 (0.72, 0.97)* | 0 | 3.8 |
| Liver | 1 | 0.84 (0.56, 1.26) | — | — |
| Breast | 5 | 0.92 (0.84, 1.02) | 14.2 | 4.6 |
| Ovarian | 3 | 0.97 (0.78, 1.21) | 0 | 1.5 |
| Leukemia | 3 | 0.69 (0.32, 1.52) | 87.3 | 15.7* |
| Endometrial | 2 | 0.77 (0.30, 2.02) | 85.2 | 6.7* |
| Glioma | 2 | 1.15 (0.75, 1.75) | 0 | 0.8 |
| Linear dose-response association (per 5-g/d increase in total nut intake)6 | ||||
| Overall cancer | 32 | 0.97 (0.95, 0.98)* | 61.7 | 80.8* |
| Study design | ||||
| Prospective | 29 | 0.98 (0.96, 0.99)* | 31.4 | 40.8 |
| Case-control | 3 | 0.78 (0.61, 1.01) | 94.9 | 39.4* |
| Specific cancers | ||||
| Colorectal | 3 | 0.78 (0.59, 1.03) | 93.5 | 30.9* |
| Colon | 4 | 0.75 (0.60, 0.94)* | 84.8 | 19.6* |
| Rectal | 3 | 0.80 (0.53, 1.20) | 90 | 21.9* |
| Lung | 4 | 0.97 (0.95, 0.98)* | 0 | 1.9 |
| Esophageal | 5 | 0.91 (0.80, 1.04) | 59 | 9.7* |
| Gastric | 4 | 0.93 (0.83, 1.04) | 61.4 | 7.7* |
| Pancreatic | 5 | 0.94 (0.89, 0.99)* | 16.9 | 4.8 |
| Breast | 4 | 0.98 (0.96, 0.99)* | 0 | 0 |
1
ES, effect size; RR, relative risk.
2
Number of effect sizes.
3
Obtained from the random-effects model.
4
Inconsistency – the percentage of variation across studies due to heterogeneity.
5
Obtained from the Q-test.
6
Total nut intake consisted of tree nut and peanut consumption.
*
P value < 0.05.