Acquired obesity is associated with increased liver fat, intra-abdominal fat, and insulin resistance in young adult monozygotic twins.
We determined whether acquired obesity is associated with increases in liver or intra-abdominal fat or impaired insulin sensitivity by studying monozygotic (MZ) twin pairs discordant and concordant for obesity. We studied nineteen 24- to 27-yr-old MZ twin pairs, with intrapair differences in body weight ranging from 0.1 to 24.7 kg [body mass index (BMI) range 20.0-33.9 kg/m2], identified from a population-based FinnTwin16 sample. Fat distribution was determined by magnetic resonance imaging, percent body fat by dual-energy X-ray absorptiometry, liver fat by proton spectroscopy, insulin sensitivity by measuring the fasting insulin concentration, and whole body insulin sensitivity by the euglycemic insulin clamp technique. Intrapair differences in BMI were significantly correlated with those in intra-abdominal fat (r = 0.82, P < 0.001) and liver fat (r = 0.57, P = 0.010). Intrapair differences in fasting insulin correlated with those in subcutaneous abdominal (r = 0.60, P = 0.008), intra-abdominal (r = 0.75, P = 0.0001) and liver (r = 0.49, P = 0.048) fat. Intrapair differences in whole body insulin sensitivity correlated with those in subcutaneous abdominal (r = -0.72, P = 0.001) and intra-abdominal (r = -0.55, P = 0.015) but not liver (r = -0.20, P = 0.20) fat. We conclude that acquired obesity is associated with increases in intra-abdominal and liver fat and insulin resistance, independent of genetic factors.
Pietiläinen
Kirsi Hannele
KH
Department of Public Health, University of Helsinki, Helsinki, Finland. kirsi.pietilainen@helsinki.fi
Rissanen
Aila
A
Kaprio
Jaakko
J
Mäkimattila
Sari
S
Häkkinen
Anna-Maija
AM
Westerbacka
Jukka
J
Sutinen
Jussi
J
Vehkavaara
Satu
S
Yki-Järvinen
Hannele
H
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D005234:Fatty Liver / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D007333:Insulin Resistance / Q000235:genetics / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009765:Obesity / Q000235:genetics / Q000378:metabolism*; D018709:Statistics, Nonparametric; D014430:Twins, Monozygotic / Q000378:metabolism*
D001786:Blood Glucose