title: Serum 25-hydroxyvitamin D and insulin resistance in people at high risk of cardiovascular disease: a euglycaemic hyperinsulinaemic clamp study.
abstract: In observational studies, low serum 25-hydroxyvitamin D (25-OHD) concentration is associated with an increased risk of type 2 diabetes mellitus (DM). Increasing serum 25-OHD may have beneficial effects on insulin resistance or beta-cell function. Cross-sectional studies utilizing suboptimal methods for assessment of insulin sensitivity and serum 25-OHD concentration provide conflicting results.
  
  
  
  This study examined the relationship between serum 25-OHD concentration and insulin resistance in healthy overweight individuals at increased risk of cardiovascular disease, using optimal assessment techniques.
  
  
  
  A total of 92 subjects (mean age 56·0, SD 6·0 years), who were healthy but overweight (mean body mass index 30·9, SD 2·3 kg/m(2) ), underwent assessments of insulin sensitivity (two-step euglycaemic hyperinsulinaemic clamp, HOMA2-IR), beta-cell function (HOMA2%B), serum 25-OHD concentration and body composition (DEXA).
  
  
  
  Mean total 25-OHD concentration was 32·2, range 21·8-46·6 nmol/l. No association was demonstrated between serum 25-OHD concentration and insulin resistance.
  
  
  
  In this study using optimal assessment techniques to measure 25-OHD concentration, insulin sensitivity and body composition, there was no association between serum 25-OHD concentration and insulin resistance in healthy, overweight individuals at high risk of developing cardiovascular disease. This study suggests the documented inverse association between serum 25-OHD concentration and risk of type 2 DM is not mediated by a relationship between serum 25-OHD concentration and insulin resistance.
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.|Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, Belfast, UK.
authors.forename: I R
authors.initials: IR
authors.lastname: Wallace
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: M C
authors.initials: MC
authors.lastname: McKinley
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: C T
authors.initials: CT
authors.lastname: McEvoy
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: L L
authors.initials: LL
authors.lastname: Hamill
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: C N
authors.initials: CN
authors.lastname: Ennis
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: A
authors.initials: A
authors.lastname: McGinty
authors.affiliation: Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, Belfast, UK.
authors.forename: P M
authors.initials: PM
authors.lastname: Bell
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: C C
authors.initials: CC
authors.lastname: Patterson
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: J V
authors.initials: JV
authors.lastname: Woodside
authors.affiliation: Centre for Public Health, Queen's University Belfast, Institute of Clinical Science B, Belfast, UK.
authors.forename: I S
authors.initials: IS
authors.lastname: Young
authors.affiliation: Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, Belfast, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Hunter
mesh_terms: D002318:Cardiovascular Diseases; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2; D006801:Humans; D007333:Insulin Resistance; D008875:Middle Aged; D050177:Overweight; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D