Gender differences in plasma ghrelin and its relations to body composition and bone – an opposite‐sex twin study

BACKGROUND: Ghrelin, a peptide hormone that plays a role in the regulation of appetite and body adiposity, may also play a role in bone metabolism. OBJECTIVES: We used the opposite-sex twin model to study associations of plasma ghrelin levels with measures of bone mass and body composition, and determine how such associations were influenced by gender and age. PATIENTS AND MEASUREMENTS: We measured total plasma ghrelin by radioimmunoassay (RIA) and bone mass/body composition parameters by dual energy X-ray absorptiometry in 79 pairs of opposite sex twins (n = 158 subjects). To examine the effect of age, the study population was divided by median age into two groups: under 51.2 years (38 pairs) and over 51.2 years (41 pairs). RESULTS: Women had higher plasma ghrelin levels than men (median 1063 vs. 869 ng/l, P 30) no significant gender differences in plasma ghrelin were found. Plasma ghrelin levels were not significantly associated with bone mineral density (BMD) generally, except for hip BMD in younger women (r = -0.39). CONCLUSION: Plasma ghrelin levels are associated with age, gender, alcohol intake and fat mass measures but only weakly to bone mass measures.