A positive association between homeostasis model assessment of insulin resistance score and the Trp64Arg Polymorphism of the β3-adrenergic receptor gene in schizophrenia patients in Taiwan

Objective: To investigate the possible association between the Trp64Arg polymorphism of the β3-adrenergic receptor gene and the homeostasis model assessment of insulin resistance (HOMA-IR) index in schizophrenia patients in Taiwan. Method: A total of 203 inpatients who met DSM-IV diagnostic criteria for schizophrenia were recruited from a psychiatry center in Taiwan from September 2002 to August 2003. All patients had been treated with antipsychotics for at least 6 months. The genotyping of the Trp64Arg polymorphism of the β3-adrenergic receptor gene was done by the polymerase chain reaction-restriction fragment length polymorphism method with the restriction enzyme MvaI. The HOMA-IR index was used to indicate the degree of insulin resistance. Results: After adjusting for sex, age, and body mass index status, the association between the HOMA-IR index and the Trp64Arg polymorphism of the β3-adrenergic receptor gene was still positive (regression coefficient = -0.65, P=.033). Conclusions: The polymorphism of the β3-adrenergic receptor gene may be related to the development of insulin resistance in chronic schizophrenia patients in Taiwan.