Mediterranean diet and the risk of chronic kidney disease: A systematic review and meta-analysis

Objective: Mediterranean diet has been shown to be associated with lower risk of cardiovascular disease. However, its association with chronic kidney disease (CKD) remains inconclusive as the results were not consistent among population-based studies. This study aims to assess the association between Mediterranean diet adherence and CKD prevention. Methods: We performed a systematic review and meta-analysis of studies describing the risk for CKD in community-dwelling subjects ≥18 years of age. Mediterranean diet adherence was assessed by standardized food frequency questionnaires. The search was conducted through MEDLINE, EMBASE and Cochrane Library. Results: Of 168 citations, a total of nine (n = 19 151) and four studies (n = 8467) were included in the systematic review and meta-analysis, respectively. Only studies adopting Mediterranean Diet Scale (MDS) were included in the analysis. The mean score was 3.8 ± 0.3 points. With the mean follow-up duration of 20.6 ± 7.0 years, the pooled odds ratio (OR) for CKD was 0.901 (95% confidence interval [CI] 0.868-0.935) for each 1-point increment of MDS. The incidence of CKD was 0.026 events per person-year (95% CI 0.008-0.045). Moreover, male sex was associated with the incidence of CKD in an adjusted meta-regression analysis. In contrast, there was no significant association between age, black race, smoking, diabetes, hypertension estimated glomerular filtration rate and total daily energy intake vs CKD incidence. Conclusion: Adherence to Mediterranean diet by a 1-point increment of MDS was associated with 10% lower risk of CKD. However, there were insufficient data on patients with pre-existing CKD or dialysis.