title: Association between the 4 bp proinsulin gene insertion polymorphism (IVS-69) and body composition in black South African women.
abstract: The objective of the study was to examine the association between a functional 4 bp proinsulin gene insertion polymorphism (IVS-69), fasting insulin concentrations, and body composition in black South African women. Body composition, body fat distribution, fasting glucose and insulin concentrations, and IVS-69 genotype were measured in 115 normal-weight (BMI<25 kg/m2) and 138 obese (BMI>or=30 kg/m2) premenopausal women. The frequency of the insertion allele was significantly higher in the class 2 obese (BMI>or=35 kg/m2) compared with the normal-weight group (P=0.029). Obese subjects with the insertion allele had greater fat mass (42.3+/-0.9 vs. 38.9+/-0.9 kg, P=0.034) and fat-free soft tissue mass (47.4+/-0.6 vs. 45.1+/-0.6 kg, P=0.014), and more abdominal subcutaneous adipose tissue (SAT, 595+/-17 vs. 531+/-17 cm2, P=0.025) but not visceral fat (P=0.739), than obese homozygotes for the wild-type allele. Only SAT was greater in normal-weight subjects with the insertion allele (P=0.048). There were no differences in fasting insulin or glucose levels between subjects with the insertion allele or homozygotes for the wild-type allele in the normal-weight or obese groups. In conclusion, the 4 bp proinsulin gene insertion allele is associated with extreme obesity, reflected by greater fat-free soft tissue mass and fat mass, particularly SAT, in obese black South African women.
authors.affiliation: Division of Chemical Pathology, UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Cape Town, South Africa. peter.berman@uct.ac.za
authors.forename: Peter
authors.initials: P
authors.lastname: Berman
authors.forename: Malcolm
authors.initials: M
authors.lastname: Collins
authors.forename: Ingrid
authors.initials: I
authors.lastname: Baumgarten
authors.forename: Cathal
authors.initials: C
authors.lastname: Seoighe
authors.forename: Courtney L
authors.initials: CL
authors.lastname: Jennings
authors.forename: Yael
authors.initials: Y
authors.lastname: Joffe
authors.forename: Estelle V
authors.initials: EV
authors.lastname: Lambert
authors.forename: Naomi S
authors.initials: NS
authors.lastname: Levitt
authors.forename: Mirjam V
authors.initials: MV
authors.lastname: Faulenbach
authors.forename: Steven E
authors.initials: SE
authors.lastname: Kahn
authors.forename: Julia H
authors.initials: JH
authors.lastname: Goedecke
mesh_terms: D050154:Adiposity / Q000208:ethnology / Q000235:genetics; D044383:Black People / Q000235:genetics*; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition / Q000235:genetics*; D016022:Case-Control Studies; D005215:Fasting; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007328:Insulin / Q000097:blood; D016254:Mutagenesis, Insertional; D009765:Obesity / Q000208:ethnology* / Q000235:genetics* / Q000473:pathology; D010641:Phenotype; D011110:Polymorphism, Genetic; D017697:Premenopause / Q000235:genetics; D011384:Proinsulin / Q000235:genetics*; D012720:Severity of Illness Index; D013019:South Africa / Q000453:epidemiology; D050151:Subcutaneous Fat / Q000473:pathology
chemical_list: D001786:Blood Glucose; D007328:Insulin; D011384:Proinsulin