The relationship between leukocyte mitochondrial DNA contents and metabolic syndrome in postmenopausal women

Objective: Menopause is associated with increased risk of metabolic syndrome. There is growing evidence that mitochondrial dysfunction may lead to obesity and insulin resistance, which are major components of metabolic syndrome. The purpose of this study was to illuminate the relationship between mitochondrial function using leukocyte mitochondrial DNA copy number and metabolic syndrome in postmenopausal women. Methods: The present study included 144 postmenopausal women. Women with cardiovascular disease were excluded from the study sample. Anthropometric evaluation and biochemical tests were performed. Leukocyte mitochondrial DNA copy numbers were then measured. Results: The levels of leukocyte mitochondrial DNA copy number were lower among participants with metabolic syndrome than among those without metabolic syndrome (P < 0.01). As the number of components of metabolic syndrome increased, the concentration of leukocyte mitochondrial DNA copy number decreased (P = 0.02). Leukocyte mitochondrial DNA copy number was negatively correlated with waist circumference (r = -0.19, P = 0.03), fasting insulin (r = -0.19, P = 0.03), total cholesterol (r = -0.22, P < 0.01), and triglyceride (r = -0.37, P < 0.01). Leukocyte mitochondrial DNA copy number was positively associated with serum 25-hydroxyvitamin D levels (r = 0.94, P = <0.01). Multiple logistic regression analysis showed that leukocyte mitochondrial DNA copy number (odds ratio, 0.030; 95% CI, 0.002-0.437, P = 0.01) was independently associated with metabolic syndrome after adjustment for potential confounding variables including age, body mass index, homeostasis model assessment of insulin resistance, 25-hydroxyvitamin D, adiponectin, and high-sensitivity C-reactive protein. Conclusions: Leukocyte mitochondrial DNA copy number was independently associated with metabolic syndrome in postmenopausal women.