Relationship between circulating leptin levels and arterial stiffness: a systematic review and meta-analysis of observational studies

Introduction: Leptin is associated with cardiovascular risk. Some studies analyzed the potential association between leptin and arterial stiffness, an independent cardiovascular risk factor. However, the studies that investigated this association provided inconsistent and heterogeneous results. Aim: We performed a systematic review and a meta-analysis of the available studies on the relationship between leptin and arterial stiffness to achieve definitive conclusions. Methods: A systematic search of the on-line databases available (up to December 2019) was conducted including the observational studies that reported the evaluation of the relationship between non-invasively assessed arterial stiffness (expressed by carotid-femoral pulse wave velocity) and leptin. For each study, the effect size was standardized and pooled using a random effect model. Sensitivity analysis, heterogeneity, publication bias, meta-regression and sub-group analyses were also assessed. Results: Ten studies met the pre-defined inclusion criteria and provided 11 cohorts with 7,580 total participants. Leptin levels were positively and significantly associated with risk of increased arterial stiffness (odds ratio 1.04; p < 0.01), with no significant heterogeneity among studies. Likewise, pooled analysis of correlation showed a significant and positive association between leptin and pulse wave velocity (z = 0.27, p < 0.01), with significant heterogeneity among studies. Conclusion: The results of this meta-analysis indicate that leptin is positively associated with arterial stiffness. This association significantly adds to the recognized value of leptin in cardiovascular disease.