Table 1.
Characteristics of meta-analyses and RCTs included in the review
| Authors, year and reference | Design (meta-analysis or RCT) | Evaluation | Population | Outcome | Quality (meta-analyses), risk of bias (RCT) | Results (95% CI) |
|---|---|---|---|---|---|---|
| Esposito et al, 201116 | Meta-analysis (15 RCTs) | Body weight (kg) | Obese and/or type 2 diabetes | Mean difference | Moderate | −1.75 (−2.86 to −0.64) |
| Nordmann et al, 201117 | Meta-analysis (6 RCTs) | Body weight (kg) | Mixed | Mean difference | Moderate | −2.2 (−3.9 to −0.6) |
| Cholesterol (mg/dL) | Mean difference | −7.4 (−10.3 to −4.4) | ||||
| Ajala et al, 201318 | Meta-analysis (3 RCTs) | Body weight (kg) | Type 2 diabetes | Mean difference | Moderate | −1.84 (−2.54 to −1.15) |
| HbA1c (%) | Mean difference | −0.41 (−0.58 to −0.24) | ||||
| HDL-C (mg/dL) | Mean difference | 1.54 (0.38 to 2.71) | ||||
| Rees et al, 201319 | Meta-analysis (4 RCTs) | Cholesterol (mg/dL) | Mixed | Mean difference | Moderate/high | −8.9 (−10.4 to −7.7) |
| Huo et al, 201420 | Meta-analysis (11 RCTs) | Body weight (kg) | Type 2 diabetes | Mean difference | Moderate | −0.29 (−0.55 to −0.04) |
| HbA1c | Mean difference | −0.30 (−0.61 to −0.38) | ||||
| Cholesterol (mg/dL) | Mean difference | −5.4 (−7.3 to −3.5) | ||||
| HDL-C (mg/dL) | Mean difference | 2.31 (0.77 to 3.86) | ||||
| Carter et al, 201421 | Meta-analysis (3 RCTs) | HbA1c (%) | Type 2 diabetes | Mean difference | Low/moderate | −0.30 (−0.61 to −0.03) |
| Koloverou et al, 201422 | Meta-analysis (1 RCT, 9 cohorts) | Incidence of diabetes | Without diabetes at baseline | Relative risk | Moderate | 0.77 (0.66 to 0.89) |
| Schwingshackl et al, 201523 | Meta-analysis (1 RCT, 8 cohorts) | Incidence of diabetes | Without diabetes at baseline | Relative risk | Moderate | 0.81 (0.73 to 0.90) |
| Esposito et al, 200424 | RCT | Remission from MS | People with MS | HR | Low | 1.74 (1.36 to 2.21) |
| Babio et al, 201425 | RCT* | Remission from MS | People with MS | HR | Low | 1.32 (1.12 to 1.55) |
| Toobert et al, 200326 | RCT | HbA1c (%) | Type 2 diabetes | Mean difference | Unclear | −0.34 (−0.67 to −0.01) |
| Elhayany et al, 201027 | RCT | HbA1c (%) | Type 2 diabetes | Mean difference | Low | −0.28 (−0.63 to −0.07) |
| Esposito et al, 201428 | RCT | HbA1c (%) | Type 2 diabetes | Mean difference | Low | −0.50 (−0.60 to −0.40) |
| Salas-Salvadò et al, 201429 | RCT* | Incidence of diabetes | People without diabetes | HR | Low | 0.60 (0.43 to 0.85)† |
| 0.82 (0.61 to 1.10)‡ |
*Same RCT with two different outcomes.
†Mediterranean diet supplemented with extra virgin olive oil.
‡Mediterranean diet supplemented with nuts.
Cholesterol, total cholesterol; HbA1c, glycosylated haemoglobin; HDL-C, high-density lipoprotein cholesterol; MS, metabolic syndrome; RCT, randomised controlled trial.