The Mediterranean Dietary Pattern and Inflammation in Older Adults: A Systematic Review and Meta-analysis

This systematic review and meta-analysis aimed to explore the association between the Mediterranean dietary pattern and inflammation in older adults. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A search of the literature was conducted up to June 2020 in 7 electronic databases, namely PubMed, Embase, Web of Science, Scopus, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and ProQuest. The Joanna Briggs Institute Critical Appraisal Checklists and the Newcastle-Ottawa Scale were used to assess the methodological quality. The overall standardized mean difference (SMD) and 95% CIs were estimated in random-effects meta-analyses. Thirteen studies were identified as having acceptable quality and were included in this systematic review: 3 randomized controlled trials (RCTs), 1 quasi-experimental study, 1 cohort study, and 8 cross-sectional studies. The circulating C-reactive protein (CRP) concentration was the most common inflammation indicator used. Results of the meta-analysis on 5 cross-sectional studies revealed a significant inverse association between the Mediterranean dietary pattern and inflammation as assessed by CRP (SMD = -0.26; 95% CI: -0.41, -0.11; P < 0.001). Other studies that investigated a variety of inflammation indicators other than CRP showed mixed results with regard to the relation between the Mediterranean dietary pattern and inflammation in older adults. Our findings suggest that the Mediterranean dietary pattern may be associated with lower inflammation in older adults. However, more long-term RCTs are required to demonstrate the effects of the Mediterranean dietary pattern on multiple inflammation parameters in older adults. The study has been registered on PROSPERO (#CRD42020140145).