No association of the Trp 64 Arg mutation of the beta3-adrenergic receptor gene with obesity, type 2 diabetes mellitus, hyperlipidemia, and hypertension in Japanese patients with schizophrenia.

OBJECTIVE: This study was conducted to address the question of whether the beta3-adrenergic receptor gene mutation (Trp 64 Arg) is associated with metabolic disease in Japanese patients with schizophrenia. METHODS: In a cross-sectional study, 89 participants were grouped into three genotypes. The 64 Arg allelic frequency in patients with or without metabolic disease was analyzed. Anthropometrics variables and biochemical parameters were compared among the genotypes. RESULTS: The 64Arg allele, which had a frequency of 0.22, was not associated with obesity, type 2 diabetes mellitus, dyslipidemias, or hypertension. No significant differences among the genotypes were found in current age, age at diagnosis with schizophrenia, body mass index, waist-hip ratio, plasma glucose, plasma insulin, triglycerides, free fatty acids. Patients with the 64 Arg allele had greater 24-h excretion of norepinephrine than those lacking the variant (p = 0.019). CONCLUSION: The 64 Arg allelic mutation is not associated with obesity, type 2 diabetes mellitus, lipid metabolism dysfunction, or hypertension in Japanese patients with schizophrenia.

Gender differences in association of plasma adiponectin with obesity reflect resultant insulin resistance in non-diabetic Japanese patients with schizophrenia.

Adipose tissues poorly produce adiponectin in the population with increased body fat mass and diabetes mellitus. It was investigated whether hypoadiponectinemia is associated with obesity and insulin resistance in patients with chronically medicated schizophrenia. A cross-sectional study was designed for 73 non-diabetic Japanese patients with schizophrenia. The patients aged <70 years with body mass index (BMI) > or =18.5 were selected. Anthropometrics and blood parameters including fat-derived cytokines were measured, and then the BMI and homeostasis model assessment-insulin resistance (HOMA-IR) was calculated. The variables were compared between the non-obesity (BMI, 18.5-24.9) and obesity (> or = 25.0) groups, and between genders. Plasma adiponectin negatively correlated with BMI (r = -0.554, P < 0.0003) and HOMA-IR (r = -0.380, P = 0.007) in men, but not in women. The obesity group in men, as compared with the non-obesity group, showed significantly lower plasma adiponectin (P = 0.008) and higher HOMA-IR (P < 0.05), but not in women. Plasma leptin showed a significant positive correlation with BMI (r = 0.604, P < 0.0001 in men; r = 0.763, P < 0.0001 in women) and HOMA-IR (r = 0.618, P < 0.0001 in men; r = 0.679, P < 0.0001 in women). The mean plasma leptin in the obesity group was significantly higher than that in the non-obesity group (P < 0.01 in men; P < 0.01 in women). In contrast to plasma leptin, plasma adiponectin showed gender difference in relation to BMI and HOMA-IR.