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Metabolically healthy obesity and risk of incident type 2 diabetes: a meta-analysis of prospective cohort studies

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posted on 2015-11-04, 13:35 authored by Joshua A. Bell, Mika Kivimaki, Mark Hamer
The risk of type 2 diabetes among obese adults who are metabolically healthy has not been established. We systematically searched Medline (1946–August 2013) and Embase (1947–August 2013) for prospective studies of type 2 diabetes incidence (defined by blood glucose levels or self-report) among metabolically healthy obese adults (defined by body mass index [BMI] and normal cardiometabolic clustering, insulin profile or risk score) aged ≥18 years at baseline. We supplemented the analysis with an original effect estimate from the English Longitudinal Study of Ageing (ELSA), with metabolically healthy obesity defined as BMI ≥ 30 kg m−2 and <2 of hypertension, impaired glycaemic control, systemic inflammation, adverse high-density lipoprotein cholesterol and adverse triglycerides. Estimates from seven published studies and ELSA were pooled using random effects meta-analyses (1,770 healthy obese participants; 98 type 2 diabetes cases). The pooled adjusted relative risk (RR) for incident type 2 diabetes was 4.03 (95% confidence interval = 2.66–6.09) in healthy obese adults and 8.93 (6.86–11.62) in unhealthy obese compared with healthy normal-weight adults. Although there was between-study heterogeneity in the size of effects (I2 = 49.8%; P = 0.03), RR for healthy obesity exceeded one in every study, indicating a consistently increased risk across study populations. Metabolically healthy obese adults show a substantially increased risk of developing type 2 diabetes compared with metabolically healthy normal-weight adults. Prospective evidence does not indicate that healthy obesity is a harmless condition.


National Institute on Aging in the United States. Grant Numbers: 2RO1AG7644-01A1, 2RO1AG017644, AG034454 Economic and Social Research Council (ESRC) Medical Research Council. Grant Number: K013351 National Heart, Lung and Blood Institute. Grant Number: HL36310 Academy of Finland an ESRC professorial fellowship British Heart Foundation. Grant Number: RE/10/005/28296



  • Sport, Exercise and Health Sciences

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Obesity Reviews


BELL, J.A., KIVIMAKI, M. and HAMER, M., 2014. Metabolically healthy obesity and risk of incident type 2 diabetes: a meta-analysis of prospective cohort studies. Obesity Reviews, 15 (6), pp. 504–515.


© The Authors. Obesity Reviews published by John Wiley & Sons Ltd on behalf of International Association for the Study of Obesity.


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