Associations of dietary inflammatory index with metabolic syndrome and its components: a systematic review and meta-analysis

Objective: Inflammation has been suggested to play an important role in the development and progression of metabolic syndrome (MetS). Dietary inflammatory index (DII), a measurement of inflammatory potential in diets, was suggested to be associated with MetS. The aim of this systematic review and meta-analysis was to establish the associations of DII with MetS and its components based on available observational studies. Design: Systematic review and meta-analysis. Setting: A comprehensive literature search of studies that assessed the associations between DII and MetS was conducted in PubMed, Medline and Embase, using a combination of search terms relating to DII and MetS. Participants: Eighteen articles were eligible, of which fourteen were cross-sectional and four were cohort in design. Results: Results from the random effects meta-analysis showed significantly positive associations of higher DII (top v. bottom quartiles) with MetS (OR: 1 center dot 23 (95 % CI 1 center dot 10, 1 center dot 37)), abdominal obesity (OR: 1 center dot 15 (95 % CI 1 center dot 02, 1 center dot 29)), high blood pressure (OR: 1 center dot 17 (95 % CI 1 center dot 07, 1 center dot 29)), hyperglycaemia (OR: 1 center dot 18 (95 % CI 1 center dot 05, 1 center dot 33)) and hypertriacylglycerolaemia (OR: 1 center dot 17 (95 % CI 1 center dot 07, 1 center dot 28)). The effects of summary OR became stronger when analyses were restricted to cohorts, studies that adjudged for covariates (including BMI, physical activity and total energy intake). Conclusions: Higher DII, representing pro-inflammatory diet, is associated with higher odds of MetS and its components, except for low HDL-cholesterol. The findings prompt dietary interventions for preventing MetS from the aspect of inflammation.