title: Metabolically healthy obesity and cardiovascular events: A systematic review and meta-analysis.
abstract: Previous studies have provided inconsistent results about the cardiovascular risks for participants with metabolically healthy obesity (MHO). These uncertainties might partly reflect the lack of a uniform definition of MHO. We conducted a systematic review and meta-analysis to examine whether there is a suitable approach that identifies obese participants who are not at an increased risk of cardiovascular events compared with healthy normal-weight participants.
  
  
  
  Twenty-two prospective studies were eligible for the meta-analysis. Using random-effect models, pooled relative risks (RRs) were calculated for the combined effects of obesity with the presence or absence of metabolic syndrome, insulin resistance, hypertension, diabetes, hyperlipidaemia and any of these metabolic factors. Participants with MHO defined by the absence of metabolic syndrome were at increased risk for cardiovascular events compared with healthy normal-weight participants (pooled RR 1.45, 95% confidence interval (CI) 1.20-1.70), but had lower risks than unhealthy normal-weight (RR 2.07, 95% CI 1.62-2.65) and obese (RR 2.31, 95% CI 1.99-2.69) participants. The risk associated with participants who had MHO was particularly high over the long term. Similar risk estimates were observed when MHO was defined by other approaches.
  
  
  
  None of the approaches clearly identified an obese subgroup not at increased risk of cardiovascular events compared with normal-weight healthy participants. A benign obese phenotype might be defined by strict definitions, but insufficient studies exist to support this. More research is needed to better define MHO.
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbrücke, Germany German Center for Diabetes Research, Germany.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Eckel
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbrücke, Germany.
authors.forename: Karina
authors.initials: K
authors.lastname: Meidtner
authors.forename: Tamara
authors.initials: T
authors.lastname: Kalle-Uhlmann
authors.affiliation: German Center for Diabetes Research, Germany Institute of Diabetes Research and Metabolic Diseases of the Helmholtz Center München at the University of Tübingen, Germany Department of Internal Medicine IV, University Hospital of Tübingen, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Stefan
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbrücke, Germany German Center for Diabetes Research, Germany mschulze@dife.de.
authors.forename: Matthias B
authors.initials: MB
authors.lastname: Schulze
mesh_terms: D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D000067329:Obesity, Metabolically Benign / Q000175:diagnosis / Q000453:epidemiology*; D016017:Odds Ratio; D010641:Phenotype; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors
keywords: Body mass index; cardiovascular risk; meta-analysis; metabolically healthy obesity; systematic review