Plasma leptin levels are associated with abnormal fibrinolysis in men and postmenopausal women

Background. Leptin is a crucial mediator of satiety signals and energy balance, and its circulating levels are increased in obesity. It has recently been shown that plasma leptin levels in humans correlate with circulating insulin and to insulin secretion, This indicates that leptin may be an important link in metabolic consequences of the insulin resistance syndrome, Whether this includes abnormalities in fibrinolysis has not been studied, Methods and results. Healthy subjects (n = 165; 85 men and 80 women) from the Northern Sweden MONICA population were investigated. Anthropometric measurements, oral glucose tolerance tests and sampling for plasma leptin, lipids, fibrinogen and fibrinolytic variables were made. Leptin levels were 342% higher in women than in men and were in both sexes strongly correlated to body mass index (BMI). After adjustments for age and BMI, leptin levels correlated significantly to pre/post glucoseload insulin levels in both sexes. After further adjustment for baseline insulin levels, leptin levels were in males significantly associated with increased waist circumference (P < 0.001), low HDL cholesterol (P < 0,05), low tPA activity (P < 0.01) and high PAI-1 activity (P < 0.001), In postmenopausal females, a significant association between leptin and low tPA activity/high PAI-1 activity was seen after adjustment for age and BMI (P < 0.05). Conclusions, Circulating levels of leptin are associated with components of the insulin resistance syndrome, including defective fibrinolysis, in men and postmenopausal women, This suggests that leptin may be involved in the mediation of consequences of insulin resistance.