Article Text
Abstract
Objectives To evaluate body composition in patients with severe AS of long duration and predominant axial involvement by DXA.
Methods Forty-one AS male patients with mean age 38,9 ± 7,26 sd years old (23–50 years), and thirty-four controls matched for age, sex, race, weight, height were studied. Body composition was measured by DXA (HOLOGIC QDR 2000) and was compared in the two groups. BMD was also measured in two sites: lumbar spine (L1-L4) and femoral neck.
Comparisons were performed for the group of patients and controls. Differences were analysed using x2-test, Student test and Pearson test. Statistical significance was taken at p < 0,05.
Results Body-composition indexes (BMD g/cm2, BMC g/cm2, fat mass, lean mass, fat mass percentage) were analysed. Patients with AS had a lower total lean mass (47,72 kg ± 5,82 sd/55,34 kg ± 5,48 sd.) and lower total bone mass (1,04 g/cm2 ± 0.96 sd/1,13 g/cm2 ± 1,16 sd) in comparison with controls. The analysis of BMD-lumbar spine and BMD-femoral neck showed low values (0,996 g/cm2 ± 0,20sd/0,752 ± 0,15 sd) respectively. The diagnosis of osteoporosis/osteopenia was made by WHO criteria. Additionaly, there was a difference in the fat mass percentage, but it may be result of age rather than of disease. There was a significant correlation between the reduction of lean mass and bone mass and Schober test, weight and height (p < 0,05).
Conclusion Measures of body composition in AS patients can be important to investigate strutural severity of the disease, so prevention of deformity can be promoted early. Low values of lean mass was observed in parallel with osteoporosis, that is frequent finding in male patients with AS.
This analysis showed a positively correlation between lower total lean/bone mass and anthropometric measures, probably secondary to the pathologic loss of mobility in the spine and rizomelic joints. Then, this appropriate evaluation of the musculo-skeletal changes may be a new approach for effective rehabilitation in AS patients.