Accepted for Publication: March 21, 2015.
Published Online: May 11, 2015. doi:10.1001/jamainternmed.2015.1668.
Study concept and design: Valls-Pedret, Serra-Mir, Corella, Martínez-González, Martínez-Lapiscina, Pérez-Heras, Salas-Salvadó, Estruch, Ros.
Acquisition, analysis or interpretation of data: Valls-Pedret, Sala-Vila, Corella, de la Torre, Martínez-González, Martínez-Lapiscina, Fitó, Salas-Salvadó.
Drafting of the manuscript: Valls-Pedret, Sala-Vila, Ros.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Valls-Pedret, Sala-Vila, Martínez-Lapiscina.
Obtained funding: Corella, Martinez-González, Salas-Salvadó, Estruch, Ros.
Administrative, technical, or material support: Corella, Martínez-González, Fitó, Salas-Salvadó, Estruch, Ros.
Supervision: Valls-Pedret, Corella, Martínez-González, Martínez-Lapiscina, Fitó, Estruch, Ros.
Conflict of Interest Disclosures: Dr Salas-Salvadó has reported receiving research funding and is a nonpaid member of the scientific advisory committee of the International Nut Council. Dr Ros has reported receiving research funding and is a nonpaid member of the scientific advisory committee of the California Walnut Commission. No other disclosures were reported.
Funding/Support: The PREDIMED trial was supported by the official funding agency for biomedical research of the Spanish government, Instituto de Salud Carlos III, through grants provided to research networks specifically developed for the trial: RTIC G03/140 (Dr Estruch, principal investigator), RTIC RD 06/0045 (Dr Martínez-González, principal investigator), and Ciber Fisiopatología de la Obesidad y Nutrición (a network of biomedical research groups; Drs Corella, Martínez-González, Fitó, Salas-Salvadó, Estruch, and Ros, principal investigators).
Role of the Funder/Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and the decision to submit the manuscript for publication.
Additional Contributions: Melibea Quintana, MSc, from Consorci d'Atenció Primària de Salut (Primary Health Care Area) de l’Eixample, Barcelona, Spain, helped with neuropsychological testing. Emili Corbella, BS, from our group, provided expert assistance with statistical analyses. Neither received monetary compensation for their collaboration in the study. Supplemental foods were donated, including extravirgin olive oil (by Hojiblanca and Patrimonio Comunal Olivarero, both in Spain), walnuts (by the California Walnut Commission), almonds (by Borges, in Spain), and hazelnuts (by La Morella Nuts, in Spain). Ciber Fisiopatología de la Obesidad y Nutrición is an initiative of Instituto de Salud Carlos III, Spain. We thank the participants and staff of the PREDIMED trial for their invaluable contributions to the study.