PREvention of recurrent arrhythmias with Mediterranean diet (PREDIMAR) study in patients with atrial fibrillation: Rationale, design and methods.

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Catheter ablation aims to restore sinus rhythm. However, relapses occur in up to 30% of patients. A Mediterranean diet (MedDiet) enriched with extra-virgin olive oil (EVOO) substantially reduced the incidence of AF in the PREDIMED trial. The PREDIMAR will test a similar intervention in secondary prevention. Methods: PREDIMAR is a multicenter, randomized, single-blind trial testing the effect of a MedDiet enriched with EVOO to reduce tachyarrhythmia relapses after AF ablation. The primary outcome is the recurrence of any sustained atrial tachyarrhythmia after ablation (excluding those occurring only during the first 3 months after ablation). The target final sample size is 720 patients (360 per group) recruited from 4 Spanish hospitals. A remote intervention, maintained for 2 years, is delivered to the active intervention group including periodic phone calls by a dietitian and free provision of EVOO. The control group will receive delayed intervention after trial completion. Routine electrocardiogram (ECG) and Holter ECG are performed, and a portable cardiac rhythm monitoring device is provided to be worn by participants during 15 months. Results: Recruitment started in March 2017. Up to July 2019, 609 patients were randomized (average inclusion rate: 5.3 patients/wk). Retention rates after 18 months are >94%. Conclusions: If our hypothesis is confirmed, the utility of the MedDiet enriched with EVOO in slowing the progression of AF will be proven, preventing recurrences and potentially reducing complications.

Olive oil intake and risk of atrial fibrillation in the SUN cohort.

BACKGROUND AND AIMS: A Mediterranean-type diet enriched with extra virgin olive oil has been associated with a reduction in the incidence of atrial fibrillation (AF) in a population at high cardiovascular risk. However, no study has replicated these findings. In our study, we analyzed the association between olive oil consumption and AF in the SUN project, a cohort with young Spanish adults at low cardiovascular risk. METHODS AND RESULTS: We included all participants without prevalent AF at baseline (18,118 participants). Incident AF cases were confirmed by a cardiologist following a prespecified protocol. We used multivariable repeated-measurement Cox models adjusted for possible confounders (sex, age, BMI, and several classic cardiovascular risk factors). After a mean follow-up of 10.1 years, 94 AF incident cases were confirmed. Comparing to the lowest category of consumption (<7.9 g/d), the multivariable models showed hazard ratios (IC 95%) of 1.52 (0.93-2.48) for low-to-moderate, 1.44 (0.83-2.47) for moderate-to-high and 1.27 (0.56-2.86) for high olive oil intake. In a subgroup analysis stratified by overweight, an inverse although non-significant association was found only among overweight participants when we compared the highest vs the lowest category of consumption (p for interaction = 0.043). CONCLUSION: No association between olive oil and AF was found in this low-risk cohort, although the effect of extra-virgin olive oil on AF prevention especially among people with overweight deserves further investigation.

Nut consumption and 5-y all-cause mortality in a Mediterranean cohort: the SUN project.

OBJECTIVE: The aim of this study was to assess the association between nut consumption and all-cause mortality after 5-y follow-up in a Spanish cohort. METHODS: The SUN (Seguimiento Universidad de Navarra, University of Navarra Follow-up) project is a prospective cohort study, formed by Spanish university graduates. Information is gathered by mailed questionnaires collected biennially. In all, 17 184 participants were followed for up to 5 y. Baseline nut consumption was collected by self-reported data, using a validated 136-item semi-quantitative food frequency questionnaire. Information on mortality was collected by permanent contact with the SUN participants and their families, postal authorities, and the National Death Index. The association between baseline nut consumption and all-cause mortality was assessed using Cox proportional hazards models to adjust for potential confounding. Baseline nut consumption was categorized in two ways. In a first analysis energy-adjusted quintiles of nut consumption (measured in g/d) were used. To adjust for total energy intake the residuals method was used. In a second analysis, participants were categorized into four groups according to pre-established categories of nut consumption (servings/d or servings/wk). Both analyses were adjusted for potential confounding factors. RESULTS: Participants who consumed nuts ≥2/wk had a 56% lower risk for all-cause mortality than those who never or almost never consumed nuts (adjusted hazard ratio, 0.44; 95% confidence intervals, 0.23-0.86). CONCLUSION: Nut consumption was significantly associated with a reduced risk for all-cause mortality after the first 5 y of follow-up in the SUN project.

Adherence to the Mediterranean dietary pattern and heart rate in the SUN project.

BACKGROUND: A higher heart rate has been related to an increase of total and cardiovascular mortality. The aim of this study was to assess the relation between adherence to the Mediterranean diet and heart rate. DESIGN: The SUN project is an ongoing multipurpose cohort study based on university graduates from Spain. METHODS: This cross-sectional study included 15,863 participants of the SUN project. Adherence to the Mediterranean dietary pattern was assessed through a validated 136-item food frequency questionnaire and calculated according to the 9-point score proposed by Trichopoulou. Multiple linear regression models were fitted to assess the relationship between adherence to the Mediterranean dietary pattern and heart rate and 95% confidence intervals were calculated. RESULTS: The multivariable-adjusted models revealed that participants with a high adherence (7--9 points) to the Mediterranean dietary pattern had a heart rate 2.2 bpm (95% CI 1.4-3.1) lower than participants with a low adherence (0--2 points). CONCLUSIONS: Adherence to the Mediterranean dietary pattern seems to be related to a lower heart rate.