Impact of circulating vaspin levels on metabolic variables in elderly twins

HeritabilityIFG Impaired fasting glucoseIGT Impaired glucose toleranceMZ MonozygoticNGT Normal glucose toleranceTo the Editor: We previously identified vaspin anddemonstrated that vaspin mRNA is exclusively expressedin the visceral white adipose tissue of Otsuka Long-EvansTokushima Fatty rats [1], and that injection of recombinantvaspin into obese mice improved insulin sensitivity [2].However, in humans the association between serum vaspinlevels and obesity variables is conflicting [3, 4], and therelationship between circulating vaspin levels and glucosemetabolism remains controversial [5, 6]. In addition tothese issues, it is still unknown whether serum vaspin levelsare influenced by genetic or environmental factors. Wetherefore investigated the association of human serumvaspin levels with various anthropometric and clinicalfactors and elucidated the relative impact of genetic andenvironmental factors.Participants were identified through the Danish TwinRegister as previously described [7]. A total of 298 elderlytwins (126 monozygotic [MZ]: 49 pairs and 28 single twinsaged 63–83 years; 172 dizygotic [DZ]: 56 pairs and 60single twins aged 62–83 years) were enrolled in the study.All participants provided their written informed consent.