Metabolically healthy and unhealthy obesity: differential effects on myocardial function according to metabolic syndrome, rather than obesity.
BACKGROUND
The term 'metabolically healthy obese (MHO)' is distinguished using body mass index (BMI), yet BMI is a poor index of adiposity. Some epidemiological data suggest that MHO carries a lower risk of cardiovascular disease (CVD) or mortality than being normal weight yet metabolically unhealthy.


OBJECTIVE
We aimed to undertake a detailed phenotyping of individuals with MHO by using imaging techniques to examine ectopic fat (visceral and liver fat deposition) and myocardial function. We hypothesised that metabolically unhealthy individuals (irrespective of BMI) would have adverse levels of ectopic fat and myocardial dysfunction compared with MHO individuals.


METHODS
Individuals were categorised as non-obese or obese (BMI ⩾30 kg m(-2)) and as metabolically healthy or unhealthy according to the presence or absence of metabolic syndrome.


METHODS
Sixty-seven individuals (mean±s.d.: age 49±11 years) underwent measurement of (i) visceral, subcutaneous and liver fat using magnetic resonance imaging and proton magnetic resonance spectroscopy, (ii) components of metabolic syndrome, (iii) cardiorespiratory fitness and (iv) indices of systolic and diastolic function using tissue Doppler echocardiography.


RESULTS
Cardiorespiratory fitness was similar between all groups; abdominal and visceral fat was highest in the obese groups. Compared with age- and BMI-matched metabolically healthy counterparts, the unhealthy (lean or obese) individuals had higher liver fat and decreased early diastolic strain rate, early diastolic tissue velocity and systolic strain indicative of subclinical systolic and diastolic dysfunction. The magnitude of dysfunction correlated with the number of components of metabolic syndrome but not with BMI or with the degree of ectopic (visceral or liver) fat deposition.


CONCLUSIONS
Myocardial dysfunction appears to be related to poor metabolic health rather than simply BMI or fat mass. These data may partly explain the epidemiological evidence on CVD risk relating to the different obesity phenotypes.
Department of Obesity and Endocrinology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
R
R
Dobson
Department of Cardiology, University Hospital Aintree, Liverpool, UK.
M I
MI
Burgess
Department of Obesity and Endocrinology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
V S
VS
Sprung
Department of Obesity and Endocrinology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
A
A
Irwin
National Centre Sport and Exercise Medicine, Loughborough University, Loughborough, UK.
M
M
Hamer
Department of Cardiology, University Hospital Aintree, Liverpool, UK.
J
J
Jones
Department of Obesity and Endocrinology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
C
C
Daousi
Magnetic Resonance and Image Analysis Research Centre, University of Liverpool, Liverpool, UK.
V
V
Adams
Magnetic Resonance and Image Analysis Research Centre, University of Liverpool, Liverpool, UK.|Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
G J
GJ
Kemp
Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
F
F
Shojaee-Moradie
Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.
M
M
Umpleby
Department of Obesity and Endocrinology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK.
D J
DJ
Cuthbertson
D002318:Cardiovascular Diseases / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D003430:Cross-Sectional Studies; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000453:epidemiology / Q000503:physiopathology*; D007333:Insulin Resistance; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000453:epidemiology / Q000503:physiopathology*; D009765:Obesity / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D010641:Phenotype; D011446:Prospective Studies; D012307:Risk Factors