Baseline characteristics of APPLE cohort by vitamin D status
| Variable | 25(OH)D ≥20 ng/mL n=140 | 25(OH)D <20 ng/mL n=61 | All patients n=201 | p Value |
|---|---|---|---|---|
| Female | 114 (81.4%) | 53 (86.9%) | 167 (83.1%) | 0.34 |
| Age, years (SD) | 15.4 (2.6) | 16.3 (2.8) | 15.7 (2.7) | 0.05 |
| Latitude (SD)* | 39.5 (3.4) | 38.9 (3.0) | 39.3 (3.3) | 0.09 |
| Season† | ||||
| 1st quarter | 18 (12.9%) | 18 (29.5%) | 36 (17.9%) | <0.01 |
| 2nd quarter | 36 (25.7%) | 18 (29.5%) | 54 (26.9%) | |
| 3rd quarter | 43 (30.7%) | 9 (14.8%) | 52 (25.9%) | |
| 4th quarter | 43 (30.7%) | 16 (26.2%) | 59 (29.4%) | |
| Race | ||||
| White | 84 (60.0%) | 18 (29.5%) | 102 (50.7%) | <0.01 |
| Black | 27 (19.3%) | 27 (44.3%) | 54 (26.9%) | |
| Asian | 15 (10.7%) | 4 (6.6%) | 19 (9.5%) | |
| Native American | 3 (2.1%) | 0 (0.0%) | 3 (1.5%) | |
| Native Hawaiian | 4 (2.9%) | 1 (1.6%) | 5 (2.5%) | |
| Hispanic or Latino | 29 (20.7%) | 18 (29.5%) | 47 (23.4%) | 0.18 |
| History of smoking | 3 (2.1%) | 3 (4.9%) | 6 (3.0%) | 0.37 |
| Postpubertal | 91/114 (79.8%) | 46/53 (86.8%) | 137/167 (82.0%) | 0.28 |
| Household income | ||||
| <25 000 | 32/131 (24.4%) | 25/56 (44.6%) | 57/187 (30.5%) | 0.13 |
| 25–49 999 | 36/131 (27.5%) | 15/56 (26.8%) | 51/187 (27.3%) | |
| 50–74 999 | 25/131 (19.1%) | 6/56 (10.7%) | 31/187 (16.6%) | |
| 75–99 999 | 19/131 (14.5%) | 5/56 (8.9%) | 24/187 (12.8%) | |
| 100–149 999 | 12/131 (9.2%) | 4/56 (7.1%) | 16/187 (8.6%) | |
| >150 000 | 7/131 (5.3%) | 1/56 (1.8%) | 8/187 (4.3%) | |
| BMI percentile (SD) | 72.3 (24.0) | 71.5 (28.0) | 72.1 (25.2) | 0.77 |
| Duration of lupus, months (SD) | 26.7 (26.1) | 38.8 (33.2) | 30.4 (28.9) | 0.01 |
| SLEDAI (SD) | 4.2 (3.9) | 5.3 (4.4) | 4.5 (4.0) | 0.10 |
| SLICC=0 | 111 (79.3%) | 40 (65.6%) | 151 (75.1%) | 0.04 |
| Hypertension | 42/135 (31.1%) | 23/60 (38.3%) | 65/195 (33.3%) | 0.32 |
| Glomerulonephritis | 52/139 (37.4%) | 29/61 (47.5%) | 81/200 (40.5%) | 0.18 |
| Creatinine clearance (SD) | 136.5 (27.0) | 143.8 (40.6) | 138.7 (31.8) | 0.31 |
| Timed urine protein, mg/24 h (SD) | 142.0 (212.2) | 365.5 (790.8) | 214.6 (491.5) | 0.07 |
| Serologies | ||||
| Lupus anticoagulant | 50/135 (37.0%) | 18/55 (29.5%) | 68/190 (35.8%) | 0.23 |
| Anticardiolipin ab | 59/137 (43.1%) | 27/59 (45.8%) | 86/196 (43.9%) | 0.57 |
| dsDNA | 113/140 (80.7%) | 50/61 (82.0%) | 163/201 (81.1%) | 0.73 |
| Corticosteroid usage | 116 (82.9%) | 47/60 (78.3%) | 163/200 (81.5%) | 0.45 |
| ACE inhibitor usage | 32/140 (22.9%) | 17/60 (28.3%) | 49/200 (24.5%) | 0.41 |
| Vitamin D | 94/140 (67.1%) | 39/60 (65.0%) | 133/200 (66.5%) | 0.77 |
| Calcium | 87/140 (62.1%) | 33/60 (55.0%) | 120/200 (60.0%) | 0.35 |
| Baseline hsCRP (SD) | 2.2 (7.5) | 4.6 (10.4) | 2.9 (8.4) | <0.01 |
| Homocysteine (SD) | 7.3 (2.6) | 7.7 (3.8) | 7.4 (3.0) | 0.93 |
| Lipids (SD) | ||||
| Total cholesterol | 152.9 (39.3) | 158.6 (36.5) | 154.7 (38.5) | 0.16 |
| HDL cholesterol | 47.1 (13.8) | 43.5 (10.8) | 46.0 (13.0) | 0.24 |
| LDL cholesterol | 83.6 (31.8) | 91.6 (30.0) | 86.0 (31.4) | 0.03 |
| Triglycerides | 111.4 (54.4) | 123.5 (92.9) | 115.2 (68.6) | 0.93 |
| Lipoprotein A (SD) | 21.8 (26.5) | 24.3 (22.4) | 22.6 (25.3) | 0.22 |
| Baseline mean–mean common CIMT | 0.467 (0.042) | 0.471 (0.044) | 0.468 (0.042) | 0.57 |
| Baseline mean–max CIMT | 0.580 (0.055) | 0.590 (0.056) | 0.583 (0.055) | 0.23 |
Bold denotes p values less than 0.05 to indicate statistical significance.
*Latitude is defined as the degree of latitude of the subject study centre. Latitude ranged from 32 to 48°.
†Season is defined as follows: 1st 1/1–3/31, 2nd 4/1–6/30, 3rd 7/1–9/31, 4th 10/1–12/31.
APPLE, Atherosclerosis Prevention in Pediatric Lupus Erythematosus; CIMT, carotid intima medial thickness; hsCRP, high-sensitivity C-reactive protein.