Effect of olive oil consumption on cardiovascular disease, cancer, type 2 diabetes, and all-cause mortality: A systematic review and meta-analysis

• Published in: Clinical nutrition (Edinburgh, Scotland) Scotland), 2022-12, Vol.41 (12), p.2659-2682
• Main Authors: Martínez-González, Miguel A., Sayón-Orea, Carmen, Bullón-Vela, Vanessa, Bes-Rastrollo, Maira, Rodríguez-Artalejo, Fernando, Yusta-Boyo, María José, García-Solano, Marta
• Format: Article
• Language: English
• Subjects: Cancer; Cardiovascular disease; Cardiovascular Diseases - epidemiology; Cardiovascular Diseases - etiology; Cardiovascular Diseases - prevention & control; Cohort studies; Diabetes; Diabetes Mellitus, Type 2 - complications; Diabetes Mellitus, Type 2 - epidemiology; Humans; Mediterranean diet; Monounsaturated fat; Neoplasms - complications; Neoplasms - epidemiology; Neoplasms - prevention & control; Olive Oil; Prospective Studies
• ISSN: 0261-5614; 1532-1983
• DOI: 10.1016/j.clnu.2022.10.001

Some large prospective studies on olive oil consumption and risk of chronic disease suggested protective effects. We conducted an outcome-wide systematic review and meta-analysis of prospective cohort studies and randomized controlled trials (RCT) assessing the association between olive oil consumption and the primary risk of 4 different outcomes: cardiovascular disease (CVD), cancer, type 2 diabetes (T2D) or all-cause mortality through January 2022. Thirty-six studies were included in the systematic review and twenty-seven studies (24 prospective cohorts and 3 different reports from one RCT) were assessed in 4 quantitative random-effects meta-analyses. They included a total of 806,203 participants with 49,223 CVD events; 1,285,064 participants with 58,892 incident cases of cancer; 680,239 participants with 13,389 incident cases of T2D; and 733,420 participants with 174,081 deaths. Olive oil consumption was most frequently measured with validated food frequency questionnaires. Studies follow-up ranged between 3.7 and 28 years. 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. Prospective studies supported a beneficial association of olive oil consumption with CVD, T2D and all-cause mortality, but they did not show any association with cancer risk.