Estrogen and exercise may be related to body fat distribution and leptin in young women

ObjectiveTo evaluate the effects of estrogen deficiency and exercise on body composition and leptin in young women.DesignCross-sectional clinical study.SettingVolunteers in an academic research environment.Patient(s)Three age- and body mass index–matched groups: normal-weight women with exercise-associated amenorrhea, regularly menstruating exercising control women, and regularly menstruating normally active control women.Intervention(s)Collection of blood samples and measurement of body fat and regional fat distribution by dual-energy x-ray absorptiometry.Main Outcome Measure(s)Central fat accumulation (i.e., ratio of trunk to extremity fat) and serum concentrations of E2 and leptin.Result(s)In both regularly menstruating control groups, but not in the amenorrheic women, there was a negative correlation between the serum E2 concentrations and the trunk-to-extremity fat ratio (r = −0.4), independent of age, exercise, body fat, and serum T concentrations. In all women, E2 concentrations were positively and exercise inversely correlated to leptin concentrations, independent of body fat.Conclusion(s)Estradiol level is inversely associated with central fat accumulation only in women with regular menstrual cycles. In all young premenopausal subjects, estrogen secretion influences leptin concentrations independently of body fat.