Mediterranean Diet, Inflammatory and Metabolic Biomarkers, and Risk of Alzheimer's Disease

Article type: Research Article

Authors: Gu, Yian^a | Luchsinger, Jose A.^{a; b; c; d} | Stern, Yaakov^{a; b; e} | Scarmeas, Nikolaos^{a; b; e; *}

Affiliations: [a] Taub Institute for Research of Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA | [b] Gertrude H. Sergievsky Center, Columbia University, New York, NY, USA | [c] Department of Epidemiology, Joseph P. Mailman School of Public Health, Columbia University, New York, NY, USA | [d] Division of General Medicine, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA | [e] Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA

Correspondence: [*] Correspondence to: Nikolaos Scarmeas, MD, MS, Columbia University Medical Center, 622 W 168th St., PH 19th floor, New York, NY 10032, USA. Tel.: +1 212 342 1350; Fax: +1 212 342 1838; E-mail: [email protected].

Abstract: We aimed to investigate the association between adherence to the Mediterranean diet (MeDi) and Alzheimer's disease (AD) risk in a prospective study. Specifically, we analyzed reduced inflammation and improved metabolic profile as a potential medium through which the MeDi reduced the risk of AD. During a 4-year follow-up, 118 incident AD cases were identified among the 1219 non-demented elderly (age ⩾ 65) subjects who provided dietary information and blood samples at baseline. We used high-sensitivity C-reactive protein (hsCRP) as an index of systemic inflammation, and fasting insulin and adiponectin as indexes of metabolic profile. We investigated whether there was a change in the association between MeDi and incident AD risk when the biomarkers were introduced into multivariable adjusted COX models. Better adherence to MeDi was associated with lower level of hsCRP (p = 0.003), but not fasting insulin or adiponectin. Better adherence to MeDi was significantly associated with lower risk for AD: compared to those in the lowest tertile of MeDi, subjects in the highest tertile had a 34% less risk of developing AD (p-for-trend = 0.04). Introduction of the hsCRP, fasting insulin, adiponectin, or combinations of them into the COX model did not change the magnitude of the association between MeDi and incident AD. Ultimately, the favorable association between better adherence to MeDi and lower risk of AD did not seem to be mediated by hsCRP, fasting insulin, or adiponectin. Other aspects of inflammatory and metabolic pathways not captured by these biomarkers, or non-inflammatory or non-metabolic pathways, may be relevant to the MeDi-AD association.

Keywords: Adiponectin, Alzheimer's disease, C-reactive protein, cohort studies, epidemiology, insulin, Mediterranean diet

DOI: 10.3233/JAD-2010-100897

Journal: Journal of Alzheimer's Disease, vol. 22, no. 2, pp. 483-492, 2010