title: Glycated haemoglobin is inversely related to serum vitamin D levels in type 2 diabetic patients.
abstract: OBJECTIVE
  A correlation between glucose control and 25(OH)D metabolism has been suggested by previous studies. However, this correlation has not yet been evaluated considering the impact of chronic complications of type 2 diabetes, especially the presence of nephropathy. Thus, the aim of this study was to determine the correlation between A1C and 25(OH)D in a well characterized cohort of type 2 diabetic patients.
  
  
  METHODS
  We cross-sectionally examined the association between A1C and serum 25(OH) D in 715 type 2 diabetic patients attending our clinic during the years 2011-2012. The average age was 68±12 years (range 26-94 years). The relation between A1C and serum 25(OH)D levels was modelled by multiple linear regression analyses.
  
  
  RESULTS
  Serum 25(OH)D levels were inversely associated with A1C levels (r = -0.116, p = .003). This relation maintains its independence in the multivariate analysis after adjusting for age, sex, A1C, BMI, treatment and duration of diabetes and nephropathy.
  
  
  CONCLUSIONS
  In type 2 diabetic patients, high A1C levels are associated with low concentrations of serum 25(OH)D independently of duration of diabetes, diabetic treatment and nephropathy. Future studies are needed to clarify the biological relation between glucose control and vitamin D metabolism in type 2 diabetes.
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Zoppini
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Galletti
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Targher
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Corinna
authors.initials: C
authors.lastname: Brangani
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Pichiri
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Negri
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Stoico
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Cacciatori
authors.affiliation: Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, Azienda Ospedaliera Universitaria Integrata, University of Verona, Verona, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Bonora
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications
chemical_list: D006442:Glycated Hemoglobin; D014807:Vitamin D; C517652:hemoglobin A1c protein, human