Table 4.
Outcome | No. of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerationsa | Relative (95%CI) | Quality |
---|---|---|---|---|---|---|---|---|---|
CVD incidence | 3 | Observational studies | Not serious | Not serious | Seriousb | Not serious | Dose-response gradientc | RR 0.85 (0.80 to 0.91) | ⊕⊕⊕◯◯ LOW |
CVD mortality | 14 | Observational studies | Not serious | Not serious | Not serious | Not serious | Dose-response gradientd | RR 0.77 (0.72 to 0.82) | ⊕⊕⊕◯ MODERATE |
CHD incidence | 7 | Observational studies | Not serious | Seriouse | Seriousf | Seriousg | Dose-response gradienth | RR 0.82 (0.69 to 0.96) | ⊕◯◯◯ VERY LOW |
CHD mortality | 12 | Observational studies | Not serious | Not serious | Not serious | Not serious | Dose-response gradienti | RR 0.76 (0.67 to 0.86) | ⊕⊕⊕◯ MODERATE |
Stroke incidence | 7 | Observational studies | Not serious | Not serious | Seriousj | Seriousk | None | RR 1.00 (0.92 to 1.09) | ⊕◯◯◯ VERY LOW |
Stroke mortality | 11 | Observational studies | Not serious | Not serious | Not serious | Seriousl | Dose-response gradientm | RR 0.87 (0.76 to 1.00) | ⊕⊕◯◯ LOW |
Hemorrhagic stroke | 5 | Observational studies | Seriousn | Not serious | Seriouso | Seriousp | Dose-response gradientq | RR 1.02 (0.77 to 1.34) | ⊕◯◯◯ VERY LOW |
Ischemic stroke | 7 | Observational studies | Not serious | Not serious | Seriousr | Seriouss | None | RR 0.99 (0.89 to 1.10) | ⊕◯◯◯ VERY LOW |
Atrial fibrillation | 2 | Observational studies | Not serious | Not serious | Serioust | Seriousu | None | RR 0.85 (0.73 to 0.99) | ⊕◯◯◯ VERY LOW |
Heart failure | 2 | Observational studies | Seriousv | Not serious | Seriousw | Seriousx | None | RR 1.00 (0.86 to 1.16) | ⊕◯◯◯ VERY LOW |
Abbreviations: CHD, coronary heart disease; CI, confidence interval; CVD, cardiovascular disease; GLST, generalized least squares trend; GRADE, Grading of Recommendations, Assessment, Development, and Evaluation; NOS, Newcastle-Ottawa scale, RR, risk ratio.
Publication bias could not be assessed in meta-analyses that included <10 trial comparisons. Therefore, for these outcomes, no downgrades were made for publication bias.
Serious indirectness for CVD incidence, as the included studies were conducted among health professionals and >50% of the weight (69.30%) was contributed by studies conducted among males.
Upgrade for a dose-response gradient, as the MKSPLINE dose-response analyses showed a significant nonlinear inverse relationship between total nut consumption and CVD incidence (P < 0.01); see Figure S27 in the Supporting Information online.
Upgrade for a dose-response gradient, as the MKSPLINE dose-response analyses showed a significant nonlinear inverse relationship between total nut consumption and CVD mortality (P < 0.01); see Figure S28 in the Supporting Information online.
Serious inconsistency for CHD incidence due to high degree of unexplained heterogeneity (I2 = 74%, P = 0.001).
Serious indirectness for CHD incidence, as >50% of the weight (55.4%) was contributed by studies conducted among health professionals.
Serious imprecision for CHD incidence, as the 95%CI (0.69–0.96) overlapped with the minimally important difference for clinical benefit (RR 0.95).
Upgrade for a dose-response gradient, as the GLST dose-response analyses revealed a significant linear inverse relationship between total nut consumption and CHD incidence (P < 0.01); see Figure S29 in the Supporting Information online.
Upgrade for a dose-response gradient, as the MKSPLINE dose-response analyses showed a significant nonlinear inverse relationship between total nut consumption and CHD mortality (P < 0.01); see Figure S30 in the Supporting Information online.
Serious indirectness for stroke incidence, as >50% of the weight (72.7%) was contributed by studies conducted among health professionals.
Serious imprecision for stroke incidence as the 95%CI (0.92–1.09) overlapped with the minimally important difference for clinical benefit (RR 0.95) and harm (RR 1.05).
Serious imprecision for stroke mortality, as the 95%CI (0.76–1.00) overlapped with the minimally important difference for clinical benefit (RR 0.95).
Upgrade for a dose-response gradient, as the MKSPLINE dose-response analyses showed a significant nonlinear inverse relationship between total nut consumption and stroke mortality (P = 0.029); see Figure S32 in the Supporting Information online.
Serious risk of bias for hemorrhagic stroke, as >50% of the weight (68.7%) was contributed by studies considered to be at high risk of bias (NOS < 7).
Serious indirectness for hemorrhagic stroke, as >50% of the weight (68.7%) was contributed by studies conducted among health professionals and >50% of the weight (55.7%) was contributed by studies conducted among males.
Serious imprecision for hemorrhagic stroke as the 95%CI (0.77–1.34) overlapped with the minimally important difference for clinical benefit (RR 0.95) and harm (RR 1.05).
Upgrade for a dose-response gradient, as the MKSPLINE dose-response analyses showed a significant nonlinear inverse relationship between total nut consumption and hemorrhagic stroke (P = 0.01); see Figure S33 in the Supporting Information online.
Serious indirectness for ischemic stroke, as >50% of the weight (66.1%) was contributed by studies conducted among health professionals.
Serious imprecision for ischemic stroke, as the 95%CI (0.89–1.10) overlapped with the minimally important difference for clinical benefit (RR 0.95) and harm (RR 1.05).
Serious indirectness for atrial fibrillation, as only 2 available studies were conducted among males.
Serious imprecision for atrial fibrillation, as the 95%CI (0.73–0.99) overlapped with the minimally important difference for clinical benefit (RR 0.95).
Serious risk of bias for heart failure, as >50% of the weight (65.40%) was contributed by a study considered to be at high risk of bias (NOS < 7).
Serious indirectness for heart failure, as only 2 available studies were conducted among males.
Serious imprecision for heart failure, as the 95%CI (0.86–1.16) overlapped with the minimally important difference for clinical benefit (RR 0.95) and harm (RR 1.05).