English: "Abbreviations: RR, relative risk; CI, confidence interval; RCT: randomized controlled trial. Buckland G, 2012: Cancer mortality = a; breast cancer = c. Donat-Vargas C, 2021: ENRICA Study = c."

Note that the effects could vary e.g. per cancer type. This wouldn't be clear with only a summary number. The 2015 Toledo study included above reported these results:

"After a median follow-up of 4.8 years, we identified 35 confirmed incident cases of breast cancer. Observed rates (per 1000 person-years) were 1.1 for the Mediterranean diet with extra-virgin olive oil group, 1.8 for the Mediterranean diet with nuts group, and 2.9 for the control group."

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"A 16% reduced risk of CVD (relative risk [RR]: 0.84; 95% confidence interval [CI]: 0.76 to 0.94), standardized for every additional olive oil consumption of 25 g/d was found. No significant association with cancer risk was observed (RR: 0.94; 95% CI: 0.86 to 1.03, per 25 g/d). Olive oil consumption was associated with a 22% lower relative risk of T2D (RR: 0.78; 95% CI: 0.69 to 0.87, per 25 g/d) without evidence of heterogeneity. Similarly, it was inversely associated with all-cause mortality (RR: 0.89; 95% CI: 0.85 to 0.93, per 25 g/d). Only the results for T2D were homogeneous. Specific sources of heterogeneity for the other 3 outcomes were not always apparent."

"Exploratory meta-regression analyses were conducted using the “metareg” command. Covariates explored in the meta-regression analyses were geographical origin (Mediterranean and non-Mediterranean countries), number of participants (<10,000 vs ≥ 10,000), length of the follow-up period (<10 vs ≥ 10 years), exposure assessment (olive oil quantified vs olive oil in categories), mean intake of olive oil (≥12 g/d vs < 12 g/d)."