title: Acquired obesity is associated with increased liver fat, intra-abdominal fat, and insulin resistance in young adult monozygotic twins.
abstract: 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.
authors.affiliation: Department of Public Health, University of Helsinki, Helsinki, Finland. kirsi.pietilainen@helsinki.fi
authors.forename: Kirsi Hannele
authors.initials: KH
authors.lastname: Pietiläinen
authors.forename: Aila
authors.initials: A
authors.lastname: Rissanen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Sari
authors.initials: S
authors.lastname: Mäkimattila
authors.forename: Anna-Maija
authors.initials: AM
authors.lastname: Häkkinen
authors.forename: Jukka
authors.initials: J
authors.lastname: Westerbacka
authors.forename: Jussi
authors.initials: J
authors.lastname: Sutinen
authors.forename: Satu
authors.initials: S
authors.lastname: Vehkavaara
authors.forename: Hannele
authors.initials: H
authors.lastname: Yki-Järvinen
mesh_terms: 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*
chemical_list: D001786:Blood Glucose