A posteriori dietary patterns and metabolic syndrome in adults: a systematic review and meta-analysis of observational studies

Objective: Observational studies reported potential associations between different dietary patterns and the risk of metabolic syndrome (MetS); however, a consistent perspective has not been established to date. The current systematic review and meta-analysis aimed to evaluate the relationship between a posteriori dietary patterns and MetS by pooling available data. Design: MEDLINE and EMBASE databases were searched for relevant articles published up to July 2015 with no time restriction and with English language restriction. Two independent reviewers completed study selection and data extraction. Random-effects models (DerSimonian-Laird method) were used to pool effect sizes of eligible studies. The potential sources of heterogeneity were assessed using the I-2 statistic. Results: Nineteen papers that identified dietary patterns using an a posteriori method were selected and included in the meta-analysis. The 'Healthy/Prudent' dietary pattern was inversely associated with risk of MetS (OR = 0.89; 95% CI 0.84, 0.94, P = 0.002). In contrast, the 'Unhealthy/Western' dietary pattern had a significant positive association with risk of MetS (OR = 1.16; 95% CI 1.11, 1.22, P < 0.001). Conclusions: Our findings provide evidence that greater adherence to a healthy/prudent dietary pattern is associated with a lower risk of MetS, while an unhealthy/Western dietary pattern is associated with increased risk of MetS. These data suggest that a diet based on healthy food choices is also beneficial for prevention of MetS.