title: The effect of 25-hydroxyvitamin D on insulin sensitivity in obesity: is it mediated via adiponectin?
abstract: There has been substantial recent interest in using vitamin D to improve insulin sensitivity and preventing/delaying diabetes in those at risk. There is little consensus on the physiological mechanisms and whether the association is direct or indirect through enhanced production of insulin-sensitising chemicals, including adiponectin. We examined cross-sectional associations between serum 25-hydroxyvitamin D (25(OH)D) and insulin sensitivity (Matsuda index), parathyroid hormone (PTH), waist circumference, body mass index (BMI), triglycerides (TG), total and high molecular weight (HMW) adiponectin, HMW : total adiponectin ratio (HMW : total adiponectin), and total cholesterol : HDL cholesterol ratio (TC:HDL cholesterol) in 137 Caucasian adults of mean age 43.3 ± 8.3 years and BMI 38.8 ± 6.9 kg/m(2). Total adiponectin (standardised β = 0.446; p < 0.001), waist circumference (standardised β = -0.216; p < 0.05), BMI (standardised β = -0.212; p < 0.05), and age (standardised β = -0.298; p < 0.001) were independently associated with insulin sensitivity. Serum 25(OH)D (standardised β = 0.114; p = 0.164) was not associated with insulin sensitivity, total or HMW adiponectin, HMW : total adiponectin, or lipids. Our results provide the novel finding that 25(OH)D is not associated with HMW adiponectin or HMW : total adiponectin in nondiabetic, obese adults and support the lack of association between 25(OH)D and lipids noted by others in similar groups of patients.
authors.affiliation: Centre for Dietetics Research (C-DIET-R), School of Human Movement Studies, Connell Building, The University of Queensland, Brisbane, Queensland, Australia. o.wright@uq.edu.au
authors.forename: Olivia R L
authors.initials: OR
authors.lastname: Wright
authors.forename: Ingrid J
authors.initials: IJ
authors.lastname: Hickman
authors.forename: William G
authors.initials: WG
authors.lastname: Petchey
authors.forename: Clair M
authors.initials: CM
authors.lastname: Sullivan
authors.forename: Cynthia
authors.initials: C
authors.lastname: Ong
authors.forename: Felicity J
authors.initials: FJ
authors.lastname: Rose
authors.forename: Choaping
authors.initials: C
authors.lastname: Ng
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Prins
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Whitehead
authors.forename: Trisha M
authors.initials: TM
authors.lastname: O'Moore-Sullivan
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood* / Q000378:metabolism; D014280:Triglycerides / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: C499918:ADIPOQ protein, human; D052242:Adiponectin; D001786:Blood Glucose; D007328:Insulin; D014280:Triglycerides; D014807:Vitamin D; D002784:Cholesterol; C104450:25-hydroxyvitamin D