Olive oil consumption is associated with lower cancer, cardiovascular and all-cause mortality among Italian adults: prospective results from the Moli-sani Study and analysis of potential biological mechanisms.

BACKGROUND: Olive oil consumption has been reportedly associated with lower mortality rates, mostly from cardiovascular diseases, but its potential impact on cancer death remains controversial. Moreover, biological mechanisms possibly linking olive oil consumption to mortality outcomes remain unexplored.

METHODS: We longitudinally analysed data on 22,892 men and women from the Moli-sani Study in Italy (follow-up 13.1 y), to examine the association of olive oil consumption with mortality. Dietary data were collected at baseline (2005-2010) through a 188-item FFQ, and olive oil consumption was standardised to a 10 g tablespoon (tbsp) size. Diet quality was assessed through a Mediterranean diet score. Multivariable-adjusted Cox proportional hazard models, also including diet quality, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The potential mediating role of inflammatory, metabolic, cardiovascular and renal biomarkers on the association between olive oil intake and mortality was evaluated on the basis of change-in-estimate and associated p values.

RESULTS: Multivariable HRs for all-cause, cancer, cardiovascular and other cause mortality associated with high (>3 tbsp/d) versus low (≤1.5 tbsp/d) olive oil consumption were 0.80 (0.69-0.94), 0.77 (0.59-0.99), 0.75 (0.58-0.97) and 0.97 (0.73-1.29), respectively. Taken together, the investigated biomarkers attenuated the association of olive oil consumption with all-cause and cancer mortality by 21.2% and 13.7%, respectively.

CONCLUSIONS: Higher olive oil consumption was associated with lower cancer, cardiovascular and all-cause mortality rates, independent of overall diet quality. Known risk factors for chronic diseases only in part mediated such associations suggesting that other biological pathways are potentially involved in this relationship.