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Meta-Analysis
. 2014;39(2):271-82.
doi: 10.3233/JAD-130830.

Association of mediterranean diet with mild cognitive impairment and Alzheimer's disease: a systematic review and meta-analysis

Balwinder Singh  1 , Ajay K Parsaik  2 , Michelle M Mielke  3 , Patricia J Erwin  4 , David S Knopman  2 , Ronald C Petersen  5 , Rosebud O Roberts  5
Affiliations
Meta-Analysis

Association of mediterranean diet with mild cognitive impairment and Alzheimer's disease: a systematic review and meta-analysis

Balwinder Singh et al. J Alzheimers Dis. 2014.

Abstract

Background/objective: To conduct a systematic review of all studies to determine whether there is an association between the Mediterranean diet (MeDi) and cognitive impairment.

Methods: We conducted a comprehensive search of the major databases and hand-searched proceedings of major neurology, psychiatry, and dementia conferences through November 2012. Prospective cohort studies examining the MeDi with longitudinal follow-up of at least 1 year and reporting cognitive outcomes (mild cognitive impairment [MCI] or Alzheimer's disease [AD]) were included. The effect size was estimated as hazard-ratio (HR) with 95% confidence intervals (CIs) using the random-effects model. Heterogeneity was assessed using Cochran's Q-test and I2-statistic.

Results: Out of the 664 studies screened, five studies met eligibility criteria. Higher adherence to the MeDi was associated with reduced risk of MCI and AD. The subjects in the highest MeDi tertile had 33% less risk (adjusted HR = 0.67; 95% CI, 0.55-0.81; p < 0.0001) of cognitive impairment (MCI or AD) as compared to the lowest MeDi score tertile. Among cognitively normal individuals, higher adherence to the MeDi was associated with a reduced risk of MCI (HR = 0.73; 95% CI, 0.56-0.96; p = 0.02) and AD (HR = 0.64; 95% CI, 0.46-0.89; p = 0.007). There was no significant heterogeneity in the analyses.

Conclusions: While the overall number of studies is small, pooled results suggest that a higher adherence to the MeDi is associated with a reduced risk of developing MCI and AD, and a reduced risk of progressing from MCI to AD. Further prospective-cohort studies with longer follow-up and randomized controlled trials are warranted to consolidate the evidence. Systematic review registration number: PROSPERO 2013: CRD42013003868.

Keywords: Alzheimer's disease; Mediterranean diet; meta-analysis; mild cognitive impairment; systematic review.

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Figures

Figure 1
Figure 1
The study flowchart showing the study identification and selection
Figure 2
Figure 2
Summary of adherence to the Mediterranean diet and risk of mild cognitive impairment among cognitively normal individuals at baseline
Figure 3
Figure 3
Summary of adherence to the Mediterranean diet and risk of Alzheimer’s disease among cognitively normal individuals at baseline.
Figure 4
Figure 4
Summary adherence to the Mediterranean diet and risk of cognitive impairment
See this image and copyright information in PMC

Comment in

References

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