title: Mitochondrial Haplogroup T Is Associated with Obesity in Austrian Juveniles and Adults.
abstract: BACKGROUND
  Recent publications have reported contradictory data regarding mitochondrial DNA (mtDNA) variation and its association with body mass index. The aim of the present study was to compare the frequencies of mtDNA haplogroups as well as control region (CR) polymorphisms of obese juveniles (n = 248) and obese adults (n = 1003) versus normal weight controls (njuvenile = 266, nadults = 595) in a well-defined, ethnically homogenous, age-matched comparative cohort of Austrian Caucasians.
  
  
  RESULTS
  Using SNP analysis and DNA sequencing, we identified the nine major European mitochondrial haplogroups and CR polymorphisms. Of these, only the T haplogroup frequency was increased in the juvenile obese cohort versus the control subjects [11.7% in obese vs. 6.4% in controls], although statistical significance was lost after adjustment for sex and age. Similar data were observed in a local adult cohort, in which haplogroup T was found at a significantly higher frequency in the overweight and obese subjects than in the normal weight group [9.7% vs. 6.2%, p = 0.012, adjusted for sex and age]. When all obese subjects were considered together, the difference in the frequency of haplogroup T was even more clearly seen [10.1% vs. 6.3%, p = 0.002, OR (95% CI) 1.71 (1.2-2.4), adjusted for sex and age]. The frequencies of the T haplogroup-linked CR polymorphisms C16294T and the C16296T were found to be elevated in both the juvenile and the adult obese cohort compared to the controls. Nevertheless, no mtDNA haplogroup or CR polymorphism was robustly associated with any of several investigated metabolic and cardiovascular parameters (e.g., blood pressure, blood glucose concentration, triglycerides, cholesterol) in all obese subjects.
  
  
  CONCLUSIONS
  By investigation of this large ethnically and geographically homogenous cohort of Middle European Caucasians, only mtDNA haplogroup T was identified as an obesity risk factor.
authors: Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
authors: Sabine
authors: S
authors: Ebner
authors: Clinical Institute for Medical and Chemical Laboratory Diagnostics, Medical University Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria.
authors: Harald
authors: H
authors: Mangge
authors: Klinik Schönsicht, Berchtesgaden, Germany.
authors: Helmut
authors: H
authors: Langhof
authors: Department of Prevention, Rehabilitation and Sports Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany; Else Kröner-Fresenius-Zentrum, Klinikum rechts der Isar, Munich, Germany.
authors: Martin
authors: M
authors: Halle
authors: Department of Prevention, Rehabilitation and Sports Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Monika
authors: M
authors: Siegrist
authors: Department of Internal Medicine, Paracelsus Medical University, Salzburg, Austria; Obesity Research Unit, Paracelsus Medical University and Salzburger Landeskliniken, Salzburg, Austria.
authors: Elmar
authors: E
authors: Aigner
authors: Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria; Obesity Research Unit, Paracelsus Medical University and Salzburger Landeskliniken, Salzburg, Austria.
authors: Katharina
authors: K
authors: Paulmichl
authors: Department of Internal Medicine, Paracelsus Medical University, Salzburg, Austria.
authors: Bernhard
authors: B
authors: Paulweber
authors: Department of Internal Medicine, General Hospital Oberndorf, Oberndorf, Austria.
authors: Christian
authors: C
authors: Datz
authors: Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
authors: Wolfgang
authors: W
authors: Sperl
authors: Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
authors: Barbara
authors: B
authors: Kofler
authors: Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria; Obesity Research Unit, Paracelsus Medical University and Salzburger Landeskliniken, Salzburg, Austria.
authors: Daniel
authors: D
authors: Weghuber
mesh_terms: D000293:Adolescent; D001317:Austria; D002648:Child; D004272:DNA, Mitochondrial / Q000235:genetics*; D005006:Ethnicity / Q000235:genetics; D005260:Female; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000235:genetics*; D009765:Obesity / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012307:Risk Factors; D044465:White People / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial