Adherence to the Mediterranean diet is associated with better quality of life: data from the Osteoarthritis Initiative.

BACKGROUND
The Mediterranean diet has positively influenced various medical conditions, but only a paucity of studies has considered the relation between the Mediterranean diet and quality of life (QOL) among people living in North America.

OBJECTIVE
We investigated whether a higher adherence to the Mediterranean diet (aMED) was associated with better QOL and decreased pain, stiffness, disability, and depression in a large cohort of North Americans from the Osteoarthritis Initiative.

DESIGN
aMED was evaluated through a validated Mediterranean diet score categorized into quintiles. Outcomes of interest were QOL [assessed with the 12-Item Short-Form Health Outcome Survey (SF-12)]; disability, pain, and stiffness [assessed in both knees with the Western Ontario and McMaster Universities Arthritis Index (WOMAC)]; and depressive symptoms [assessed with the Center for Epidemiologic Studies Depression Scale (CES-D)].

RESULTS
Of the 4470 participants (2605 women; mean age: 61.3 y), those with a higher aMED had significantly more favorable scores on all outcomes investigated (P < 0.0001 for all comparisons). After adjustment for potential confounders in linear regression analyses, a higher aMED was significantly associated with a higher SF-12 physical composite scale value (β: 0.10; 95% CI: 0.05, 0.15; P < 0.0001), lower WOMAC scores (except for stiffness), and lower CES-D scores (β: -0.05; 95% CI: -0.09, -0.01; P = 0.01). An adjusted logistic regression analysis, taking as reference those in the 2 highest quintiles of the aMED score, confirmed these findings.