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Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study

BMJ 2008; 336 doi: (Published 12 June 2008) Cite this as: BMJ 2008;336:1348
  1. M Á Martínez-González, professor of epidemiology and chair1,
  2. C de la Fuente-Arrillaga, research assistant1,
  3. J M Nunez-Cordoba, research fellow12,
  4. F J Basterra-Gortari, research fellow13,
  5. J J Beunza, assistant professor1,
  6. Z Vazquez, research assistant1,
  7. S Benito, research assistant1,
  8. A Tortosa, research fellow1,
  9. M Bes-Rastrollo, assistant professor1
  1. 1Department of Preventive Medicine and Public Health, Medical School-Clinica Universitaria, University of Navarra, Pamplona, Spain
  2. 2Department of Preventive Medicine and Quality Management, Hospital Virgen del Camino, Pamplona, Spain
  3. 3Department of Endocrinology, Hospital of Navarra, Pamplona, Spain
  1. Correspondence to: M Á Martínez-González mamartinez{at}
  • Accepted 5 April 2008


Objective To assess the relation between adherence to a Mediterranean diet and the incidence of diabetes among initially healthy participants.

Design Prospective cohort study with estimates of relative risk adjusted for sex, age, years of university education, total energy intake, body mass index, physical activity, sedentary habits, smoking, family history of diabetes, and personal history of hypertension.

Setting Spanish university department.

Participants 13 380 Spanish university graduates without diabetes at baseline followed up for a median of 4.4 years.

Main outcome measures Dietary habits assessed at baseline with a validated 136 item food frequency questionnaire and scored on a nine point index. New cases of diabetes confirmed through medical reports and an additional detailed questionnaire posted to those who self reported a new diagnosis of diabetes by a doctor during follow-up. Confirmed cases of type 2 diabetes.

Results Participants who adhered closely to a Mediterranean diet had a lower risk of diabetes. The incidence rate ratios adjusted for sex and age were 0.41 (95% confidence interval 0.19 to 0.87) for those with moderate adherence (score 3-6) and 0.17 (0.04 to 0.75) for those with the highest adherence (score 7-9) compared with those with low adherence (score <3). In the fully adjusted analyses the results were similar. A two point increase in the score was associated with a 35% relative reduction in the risk of diabetes (incidence rate ratio 0.65, 0.44 to 0.95), with a significant inverse linear trend (P=0.04) in the multivariate analysis.

Conclusion Adherence to a Mediterranean diet is associated with a reduced risk of diabetes.


  • We are indebted to the participants of the SUN study for their continued cooperation and participation. We also thank others members of the SUN study group including: M Segui-Gomez, J de Irala, J A Martinez, A Marti, M Serrano-Martinez, F Guillen-Grima, E Toledo, R M Pajares, University of Navarra; M Delgado-Rodriguez, University of Jaen; J Llorca, University of Cantabria; E Smyth, University of Santiago de Compostela; A Sanchez-Villegas, University of Las Palmas; I Marques-Lopes, University of Saragossa; A Alonso, University of Minnesota; and C N Lopez, Harvard University. We thank the members of the Department of Nutrition of the Harvard School of Public Health (A Ascherio, F B Hu, W C Willett) who helped us to design the SUN study.

  • Contributors: MAM-G and MB-R were responsible for study design, recruitment of participants, and statistical analyses and wrote the first draft of the manuscript; CF-A, ZV, SB, and AT were involved in data collection, technical support, and data management; JMN-C, FJB-G, JJB, and MAM-G applied the diagnosis criteria and comprised the medical panel for the adjudication of events. MAM-G obtained funding and is guarantor. All authors provided suggestions during the different phases of the preparation of the manuscript and approved the final version submitted for publication.

  • Funding: Spanish Ministry of Health (Instituto de Salud Carlos III, Fondo de Investigaciones Sanitarias projects PI030678, PI040233, PI042241, PI050514, PI050976, PI070240; RD 06/0045) and the Navarra Regional Government (Department of Health, PI41/2005).

  • Competing interests: None declared.

  • Ethical approval: Institutional Review Board of the University of Navarra.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

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