Table 1.
Subject characteristics∗.
| Variable | Patients n = 10 |
Controls n = 10 |
p (95% CI lower; upper)∧ |
|---|---|---|---|
| Age (at time of study) | 39 ± 4.1 (33–44) | 38 ± 5.1 (31–45) | 0.57 (−3.7; 6.3) |
|
| |||
| Body height (cm) | 178.1 ± 6.4 (169.5–190.5) | 181.8 ± 6.3 (174.5–190.5) | 0.04 (−7.3; −0.2) |
|
| |||
| Femur length | 42.4 ± 2.4 (39.5–46.4) | 45.4 ± 2.4 (42.5–49.5) | 0.002 (−4.7; −1.4) |
|
| |||
| Femur length/body height (%) | 24 ± 1 (23–25) | 25 ± 1 (23–27) | 0.01 (−0.02; −0.004) |
|
| |||
| Body mass (kg) | 75.2 ± 7.8 (65.0–90.6) | 79.9 ± 11.4 (74.2–95.5) | 0.04 (−9.0; −0.3) |
|
| |||
| BMI, kg/m2 | 23.6 ± 1.3 (21.9–25.6) | 24.0 ± 2.3 (20.0–27.8) | 0.43 (−1.6; 0.7) |
|
| |||
| Smoking behavior | 0.35§ | ||
| Nonsmoker, n (%) | 8 (80) | 7 (70) | |
| Previous smoker, n (%) | 1 (10) | 3 (30) | |
| Current smoker, n (%) | 1 (10) | 0 (0) | |
|
| |||
| Full-time employment, n (%) | 10 (100) | 10 (100) | 1.00 |
|
| |||
| Level of endurance exercise (1–4) | 2.3 ± 0.7 (1–3) | 2.2 ± 0.6 (1–3) | 0.89§ |
|
| |||
| Level of strength exercise (1–4) | 1.8 ± 0.6 (1–3) | 2.0 ± 0.7 (1–3) | 0.77§ |
|
| |||
| HLA-B27 positive, n (%) | 9 (90) | — | |
|
| |||
| BASDAI score | 2.7 ± 1.1 (0–3.7) | — | |
|
| |||
| BASFI score | 0.9 ± 0.8 (0–2.6) | — | |
|
| |||
| BASMI score | 2.3 ± 1.1 (0.7–4.6) | — | |
|
| |||
| CRP, mg/L | 7.0 ± 7.7 (<1–21) | — | |
|
| |||
| ESR, mm/h | 9.3 ± 9.7 (<1–26) | — | |
|
| |||
| Anti-inflammatory medication | |||
| NSAIDs, n (%) | 6 (60) | 0 (0) | — |
| DMARDs, n (%) | 2 (20) | 0 (0) | — |
| TNF-inhibitors, n (%) | 4 (40) | 0 (0) | — |
|
| |||
| BMD, g/cm2 | 1.27 ± 0.04 (1.20–1.33) | 1.31 ± 0.13 (1.11–1.60) | 0.39 (−0.15; 0.06) |
|
| |||
| BMD, T-score | 0.65 ± 0.43 (0–1.3) | 1.09 ± 1.33 (−0.9–4.0) | 0.37 (−1.5; 0.6) |
|
| |||
| Lean body mass, kg/m2 | 18.2 ± 1.8 (15.1–21.3) | 18.6 ± 1.6 (17.1–21.6) | 0.32 (−1.2; 0.4) |
|
| |||
| Appendicular lean mass RSMI, kg/m2 | 8.3 ± 0.9 (7.2–9.6) | 8.8 ± 0.8 (8.0–10.1) | 0.02 (−0.9; −0.1) |
|
| |||
| Body fat, % | 21.9 ± 7.0 (8.4–30.2) | 20.1 ± 6.2 (12.6–31.2) | 0.47 (−3.5; 7.1) |
|
| |||
| Android fat, % | 25.3 ± 10.9 (6.3–39.7) | 21.6 ± 10.1 (10.6–36.5) | 0.31 (−4.1; 11.3) |
|
| |||
| Gynoid fat, % | 21.0 ± 6.9 (8.2–29.6) | 20.8 ± 5.7 (15.0–32.8) | 0.95 (−5.3; 5.6) |
∗Values are mean ± SD (range) unless otherwise indicated. ∧Comparison between patients and controls tested by paired samples t-test unless otherwise indicated. §Pearson chi square test. AS: ankylosing spondylitis. BASDAI: Bath AS Disease Activity Index. BASFI: Bath AS Functional Index. BASMI: Bath AS Metrology Index. BMD: bone mineral density. BMI: body mass index. CI: confidence interval. CRP: C-reactive protein. DMARDs: disease modifying antirheumatic drugs. ESR: erythrocyte sedimentation rate. NSAIDs: nonsteroidal anti-inflammatory drugs. PsA: psoriasis arthritis. RSMI: relative skeletal muscle index. SpA: spondyloarthritis. TNF: tumor necrosis factor.