Objectives: Hormonal factors playing a role in bone mass and body composition have been rarely assessed in rheumatoid arthritis (RA). In this study, we aimed to evaluate the growth hormone (GH)-insulin-like growth factor-I (IGF-I)-insulin-like growth factor binding protein-3 (IGFPB-3) axis and serum leptin levels in patients with RA and to determine whether these hormonal/growth factors may influence bone mass and body composition in RA.
Methods: Serum GH, IGF-I, IGFPB-3 and leptin were evaluated in 38 corticosteroid-treated RA patients, 14 non-RA patients under corticosteroids (corticosteroid controls, CC) and 32 healthy controls (HC). Bone density was evaluated using dual X-ray absorptiometry (DEXA), and expressed as bone mineral density (BMD), and quantitative ultrasound (QUS). Body composition was assessed by DEXA.
Results: The three groups differed regarding femoral neck, total body BMD, lean mass and QUS parameters with lower values in the RA group (all P < or = 0.05). Growth hormone was higher in RA patients (P=0.0001) while IGF-I and IGFBP-3 did not differ between the three groups. In RA patients there was a tendency to high serum leptin levels and leptin strongly correlated with fat mass (r=0.83, P<0.0001), but not with bone mass measurements or inflammatory parameters. There were no differences for lean mass, GH and leptin between CC and HC.
Conclusion: Our results suggest that these GH and leptin modifications could have an influence on both bone mass and body composition in RA.