Participant characteristics. Data are presented as means (SD) for continuous variables and number (%) of participants for dichotomous variables. Data that were not normally distributed (systemic inflammatory markers, cytokines, and insulin sensitivity) are presented as geometric means (SD).
| Variable | All Participants, n = 78 | Rheumatoid Arthritis, n = 39 | Matched Controls, n = 39 |
|---|---|---|---|
| Age, yrs | 55.5 (11.8) | 56.1 (12.4) | 54.9 (11.4) |
| BMI, kg/m2 | 30.2 (6.3) | 30.5 (7.3) | 30.0 (5.3) |
| Waist circumference, cm | 94.9 (15.5) | 95.1 (17.7) | 94.6 (13.7) |
| Race | |||
| White | 59 (76) | 29 (74) | 30 (76) |
| African American | 19 (24) | 10 (26) | 9 (24) |
| Sex | |||
| Female | 54 (69) | 27 (69) | 27 (69) |
| Male | 24 (32) | 12 (31) | 12 (31) |
| Physical activity, kCal/day | 572.8 (290.8) | 546.6 (291.4) | 605.1 (292.7) |
| Physical activity, METS h/day | 29.5 (2.5) | 29.2 (2.5) | 29.9 (2.4) |
| Disease duration, mos | NA | 159 (135) | NA |
| HAQ–Disability Index | 0.5 (0.7) | 0.7 (0.7)† | 0.00 (0.00) |
| Comorbidity Index | 1.2 (1.2) | 1.5 (1.2) † | 0.6 (0.9) |
| DAS28 mean (SD) | NA | 3.1 (1.5) | NA |
| Remission (DAS28 < 2.6) | 16 (42) | ||
| Low activity (DAS28 2.6–3.2) | 6 (16) | ||
| Moderate activity (DAS28 3.2–5.1) | 11 (29) | ||
| High activity (DAS28 > 5.1) | 5 (13) | ||
| Rheumatoid factor–positive | NA | 30/35 (86) | NA |
| Anticyclic citrullinated antibody-positive | NA | 14/15 (93) | NA |
| Erosions on radiographs present | NA | 18/30 (60) | NA |
| Medication use | NA | ||
| Etanercept | 8 (21) | NA | |
| Infliximab | 2 (5) | NA | |
| Adalimumab | 4 (10) | NA | |
| Abatacept | 5 (13) | NA | |
| Methotrexate | 29 (74) | NA | |
| Leflunomide | 1 (3) | NA | |
| Sulfasalazine | 0 | NA | |
| Hydroxychloroquine | 6 (13) | NA | |
| Nonsteroidal antiinflammatory agents | 16 (41) | 1 (5.5) | |
| Prednisone (< 0.5 mg/day) | 11 (28) | NA | |
| Systemic inflammation | |||
| hsCRP, mg/l | 3.14 (4.1) | 4.1 (5.5) | 2.4 (2.9) |
| IL-1β, pg/ml | 0.22 (5.4) | 0.32 (4.2) | 0.15 (6.3) |
| IL-6, pg/ml | 5.3 (2.8) | 9.9 (2.9)† | 2.9 (1.6) |
| IL-8, pg/ml | 8.5 (2.1) | 9.4 (1.9) | 7.7 (2.4) |
| TNF-α, pg/ml | 14.1 (2.3) | 21.6 (2.4)† | 9.4 (1.6) |
| IL-18, pg/ml | 413.0 (1.3) | 446.7 (1.2)† | 316.2 (1.4) |
| Insulin Sensitivity Index 10−5 min−1/pmol/l | |||
| All | 4.5 (2.2) | 4.0 (2.4) | 4.9 (2.1) |
| Women | 5.0 (2.3) | 4.7 (2.4) | 5.2 (2.2) |
| Men | 3.6 (2.1) | 3.1 (2.3) | 4.0 (1.9) |
| Biologic use = yes | NA | 4.8 (2.4) | NA |
| Biologic use = no | NA | 3.7(2.4) | NA |
| DMARD use = yes | NA | 4.0 (2.5) | NA |
| DMARD use = no | NA | 5.4 (1.7) | NA |
| Prednisone use = yes | NA | 3.2 (2.1) | NA |
| Prednisone use = no | NA | 4.8 (2.4) | NA |
| NEFA (mmol/l) | 0.55 (1.47) | 0.57 (1.57) | 0.53 (1.36) |
| Adiposity and muscle tissue | |||
| Abdominal total adipose area, cm2 | 430 (179) | 407 (199) | 453 (157) |
| Abdominal subcutaneous adiposity, cm2 | 306 (144) | 302 (149) | 309 (141) |
| Abdominal visceral adiposity, cm2 | 125 (98) | 105 (81)† | 144 (109) |
| Abdominal liver density, Hu | 60 (10) | 60 (9) | 60 (10) |
| Thigh total area, cm2 | 254 (65) | 253 (69) | 255 (61) |
| Thigh total adipose area, cm2 | 127 (66) | 137 (61) | 116 (70) |
| Thigh subcutaneous adiposity, cm2 | 121 (57) | 125 (58) | 117 (57) |
| Thigh intermuscular adiposity, cm2 | 11 (8) | 12 (7) | 11 (8) |
| Thigh muscle area, cm2 | 120 (36) | 116 (39) | 125 (33) |
| Thigh muscle density, Hu | 51 (5) | 50 (6) | 52 (4) |
↵† p < 0.05 for comparison with matched controls. BMI: body mass index; NA: not applicable; HAQ: Health Assessment Questionnaire; DAS28: 28-joint Disease Activity Score; hsCRP: high-sensitivity C-reactive protein; IL: interleukin; METS: metabolic equivalence units; TNF: tumor necrosis factor; DMARD: disease-modifying antirheumatic drugs; NEFA: nonesterified free fatty acids.