Table 1.
Participant Characteristics*
| Variable | All Participants (n=78) | Rheumatoid Arthritis (n=39) | Matched Controls (n=39) |
|---|---|---|---|
| Age (years) | 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 | |||
| Caucasian | 59 (76%) | 29 (74%) | 30 (76%) |
| African American | 19 (24%) | 10 (26%) | 9 (24%) |
| Gender | |||
| 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 (MET hr/day) | 29.5 (2.5) | 29.2 (2.5) | 29.9 (2.4) |
| Disease duration (months) | 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) |
| DAS-28 mean (SD) | NA | 3.1 (1.5) | NA |
| Remission (DAS-28 <2.6) | 16 (42%) | ||
| Low activity (DAS-28 2.6-3.2) | 6 (16%) | ||
| Moderate activity (DAS-28 3.2-5.1) | 11 (29%) | ||
| High activity (DAS-28 >5.1) | 5 (13%) | ||
| Rheumatoid factor positive | NA | 30/35 (86%) | NA |
| Anti-cyclic 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 anti-inflammatory 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-1beta (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-alpha (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 = No | NA | 3.2 (2.1) | NA |
| Prednisone Use = No | NA | 4.8 (2.4) | NA |
| Non-esterified free fatty acids (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 Inter-Muscular 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) |
*
Data are presented as means (SD) for continuous variables and number (percentages) of participants for dichotomous variables. Data that were not normally distributed (systemic inflammatory markers, cytokines, and insulin sensitivity) are presented as geometric means (SD).
†
p≤ 0.05 for comparison with matched controls.
BMI= Body mass index; NA= Not applicable; HAQ= Health Assessment Questionnaire; DAS- 28 = Disease activity score with 28 joint count; hsCRP = High sensitivity C-reactive protein; IL = Interleukin.