A low sympathoadrenal activity is associated with body weight gain and development of central adiposity in Pima...

To investigate the possible role of impaired sympathetic nervous system and/or adrenal medullary function in the etiology of human obesity, we studied 64 Pima Indian men (28 +/- 6 years, 101 +/- 25 kg, 34 +/- 9% body fat, mean +/- SD) in whom sympathoadrenal function was estimated at baseline by measurements of 24-hour urinary norepinephrine (NE) and epinephrine (Epi) excretion rates under weight-maintenance conditions. Body weight, body composition (hydrodensitometry), and body fat distribution (waist-to-thigh circumference ratio, W/T) were measured at baseline and follow-up. Follow-up data were available on 44 subjects who gained on average 8.4 +/- 9.5 kg over 3.3 +/- 2.1 years. In these subjects, baseline NE excretion rate, adjusted for its determinants (i.e., fat free mass, fat mass, and W/T), correlated negatively with bodyweight gain (r = -0.38; p = 0.009). Baseline Epi excretion rate correlated negatively with changes in W/T (r = -0.44; p = 0.003). In conclusion, our data show for the first time that a flow sympathetic nervous system activity is associated with body weight gain in humans. Also, a low activity of the adrenal medulla is associated with the development of central adiposity.