Are there common genetic and environmental factors behind the endophenotypes associated with the metabolic syndrome?
OBJECTIVE
The cluster of obesity, insulin resistance, dyslipidaemia and hypertension, called the metabolic syndrome, has been suggested as a risk factor for cardiovascular disease and type 2 diabetes. The aim of the present study was to evaluate whether there are common genetic and environmental factors influencing this cluster in a general population of twin pairs.


METHODS
A multivariate genetic analysis was performed on nine endophenotypes associated with the metabolic syndrome from 625 adult twin pairs of the GEMINAKAR study of the Danish Twin Registry.


RESULTS
All endophenotypes showed moderate to high heritability (0.31-0.69) and small common environmental variance (0.05-0.21). In general, genetic and phenotypic correlations between the endophenotypes were strong only within sets of physiologically similar endophenotypes, but weak to moderate for other pairs of endophenotypes. However, moderate correlations between insulin resistance indices and either obesity-related endophenotypes or triacylglycerol levels indicated that some common genetic backgrounds are shared between those components.


CONCLUSIONS
We demonstrated that, in a general population, the endophenotypes associated with the metabolic syndrome apparently do not share a substantial common genetic or familial environmental background.
Benyamin
B
B
Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, Scotland, UK.|Genetic Epidemiology, Queensland Institute of Medical Research, Brisbane, QLD, Australia.
Sørensen
T I A
TIA
Danish Epidemiology Science Centre, Institute of Preventive Medicine, Copenhagen University Hospitals, Centre for Health and Society, Copenhagen, Denmark.
Schousboe
K
K
The Danish Twin Registry, Epidemiology, Institute of Public Health, University of Southern Denmark, Sdr. Boulevard 23A, 5000, Odense C, Denmark.
Fenger
M
M
Department of Clinical Biochemistry, University Hospital of Copenhagen, Hvidovre, Denmark.
Visscher
P M
PM
Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, Scotland, UK.|Genetic Epidemiology, Queensland Institute of Medical Research, Brisbane, QLD, Australia.
Kyvik
K O
KO
The Danish Twin Registry, Epidemiology, Institute of Public Health, University of Southern Denmark, Sdr. Boulevard 23A, 5000, Odense C, Denmark. KKyvik@health.sdu.dk.
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D015992:Body Mass Index; D004777:Environment; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000235:genetics / Q000502:physiology; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000209:etiology / Q000235:genetics*; D008875:Middle Aged; D009765:Obesity / Q000235:genetics / Q000503:physiopathology; D010641:Phenotype; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic
D008055:Lipids; D008074:Lipoproteins