Tyrosine Hydroxylase Gene Microsatellite Polymorphism Associated With Insulin Resistance in Depressive Disorder

Abstract A high association between type 2 diabetes mellitus and depressive illness has been reported. Insulin resistance during depressive illness might contribute to the linkage between depression and type 2 diabetes. To determine whether the genetic polymorphisms of the tyrosine hydroxylase ([TH] HUMTH01) and insulin (INS-VNTR) genes contribute to insulin resistance in depressive illness, we analyzed the association between the polymorphisms and insulin resistance in 41 Japanese patients with depressive disorder, 204 normal control subjects, 161 cohort subjects with normal glucose tolerance (NGT) and without depressive symptomatology, and 59 NGT subjects with depressive symptomatology. The depressive patients had a significantly lower insulin sensitivity index (SI) than the control subjects ( P = .016). Depressive NGT subjects had a significantly higher homeostasis model assessment (HOMA) insulin resistance index [HOMA(R)] than the nondepressive NGT subjects ( P