The quality of evidence is downgraded by study limitations (unclear allocation concealment), by inconsistency, and by indirectness (differences between the population of interest and those studied: the majority of participants were postmenopausal women).
A Cochrane review included 11 studies with a total of 52 044 healthy adults or adults at high risk of cardiovascular disease (CVD). The majority of participants were enrolled in one large study (48 835 women; WHI). Mediterranean dietary pattern was defined as comprising at least two of the following components: (1) high monounsaturated/saturated fat ratio, (2) low to moderate red wine consumption, (3) high consumption of legumes, (4) high consumption of grains and cereals, (5) high consumption of fruits and vegetables, (6) low consumption of meat and meat products and increased consumption of fish, and (7) moderate consumption of milk and dairy products. The comparison group received either no intervention or minimal intervention.
Seven studies described the intervention as a Mediterranean diet. Clinical events were reported in only one trial (WHI; intervention not described as a Mediterranean diet but increased fruit and vegetable and cereal intake) where no statistically significant effects of the intervention were seen on fatal and non-fatal endpoints at 8 years (table ).
| Outcome | HR (95% CI) |
|---|---|
| Non-fatal MI | 0.91 (0.8 to 1.04) |
| CHD death | 1.01 (0.81 to 1.27) |
| Revascularisation | 0.91 (0.82 to 1.01) |
| Fatal stroke | 0.94 (0.65 to 1.35) |
| Non-fatal stroke | 1.04 (0.90 to 1.19) |
| Total CVD events* | 0.96 (0.89 to 1.03) |
| MI = myocardial infarction; CHD = coronary heart disease; CVD = cardiovascular disease
*CVD includes clinical MI, silent MI, death due to CHD, CABG/percutaneous coronary intervention and stroke | |
Small reductions in total cholesterol and LDL cholesterol were seen with the intervention (table ). Subgroup analyses revealed statistically significant greater reductions in total cholesterol in those trials describing the intervention as a Mediterranean diet (table ). Heterogeneity precluded meta-analyses for other outcomes. Reductions in blood pressure were seen in 3 of 5 studies reporting this outcome. None of the studies reported health-related quality of life, adverse events or costs.
| Outcome | Participants (studies) | MD (95% CI) |
|---|---|---|
| Total cholesterol, mmol/L, change from baseline | 4151 (8) | -0.16 (-0.26 to -0.06) |
| Total cholesterol (mmol/L), change from baseline, subgroup analysis | ||
| 436 (4) | -0.23 (-0.27 to -0.20) |
| 3379 (4) | -0.06 (-0.13 to 0.01) |
| LDL cholesterol, mmol/L, change from baseline | 3227 (6) | -0.07 (-0.13 to -0.01) |
Date of latest search: