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Table 2 Bivariate analysis according to each specific entity and the occurrence of 25(OH)D deficiency (25(OH)D <20 ng/ml)

From: Vitamin D deficiency in chronic inflammatory rheumatic diseases: results of the cardiovascular in rheumatology [CARMA] study

  All Rheumatoid arthritis Ankylosing spondylitis Psoriatic arthritis Controls
Variables Total 25OHD <20 25OHD ≥20 p 25OHD <20 25OHD ≥20 p 25OHD <20 25OHD ≥20 p 25OHD <20 25OHD ≥20 p 25OHD <20 25OHD ≥20 p
Female, n (%) 1545 (53.1) 554 (51.2) 796 (55.0) 0.054 220 (70.1) 280 (79.5) 0.005 92 (31.4) 81 (23.9) 0.035 127 (43.1) 162 (48.1) 0.206 115 (63.5) 273 (65.2) 0.703
Age beginning disease, years, mean (SD) 40.5 (14.5) 40.4 (14.5) 41.4 (14.7) 0.079 45.8 (13) 46.1 (13.6) 0.743 30.1 (11.7) 29.6 (11.8) 0.620 39.2 (13.1) 39.4 (13.3) 0.846 49.4 (12.6) 48.5 (12.2) 0.406
Disease duration, years, mean (SD) 11.03 (10.4) 11.5 (10.2) 10.7 (10.5) 0.005 10.1 (8.5) 10.4 (9.1) 0.782 17.6 (11.9) 17.72 (12.1) 0.950 11.2 (8.4) 11.4 (9.3) 0.983 4.4 (6.9) 4.5 (6.2) 0.321
Educational level, n (%)
 Elementary 1693 (58.6) 646 (60.4) 819 (56.8) 0.071 212 (68.6) 242 (68.9) 0.926 176 (60.7) 182 (53.8) 0.84 173 (59.5) 200 (59.5) 0.985 85 (47.5) 195 (46.9) 0.891
 University/secondary 1194 (41.4) 423 (39.6) 622 (43.2) 97 (31.4) 109 (31.1) 114 (39.3) 156 (46.2) 118 (40.5) 136 (40.5) 94 (52.5) 221 (53.1)
Smoking status, n (%)
 Current smokers 743 (25.5) 303 (28.0) 335 (23.2)   83 (24.4) 76 (21.6)   107 (36.5) 113 (33.3)   59 (20.0) 73 (21.6)   54 (30.0) 73 (17.4)  
 Past smokers 845 (29.0) 332 (30.7) 407 (28.1) 0.001 86 (27.4) 92 (26.1) 0.226 95 (32.4) 107 (31.6) 0.530 101 (34.2) 104 (30.9) 0.650 50 (27.8) 104 (24.8) <0.001
 Never smokers 1322 (45.5) 447 (41.3) 705 (48.7)   145 (46.2) 184 (52.3)   91 (31.1) 119 (35.1)   135 (45.8) 160 (47.5)   76 (42.2) 242 (57.8)  
Obesity (BMI ≥30), n (%) 2184 (75.0) 327 (30.2) 308 (21.3) 0.001 88 (28.0) 71 (20.2) 0.018 83 (28.3) 75 (22.1) 0.072 102 (34.7) 89 (26.5) 0.025 54 (30.0) 73 (17.5) 0.001
Main physical activity, n (%)
 Sedentary 1043 (39.8) 380 (39.3) 553 (40.8)   92 (34.3) 113 (36.1)   103 (39.6) 120 (38.7)   110 (41.5) 119 (39.1)   75 (42.9) 181 (47.6)  
 Moderate 976 (37.2) 363 (37.5) 472 (36.1) 0.734 113 (42.2) 136 (43.5) 0.669 90 (34.6) 109 (35.2) 0.976 100 (37.7) 107 (35.2) 0.386 60 (34.3) 120 (31.6) 0.576
 Active with displacement 604 (23.0) 225 (23.2) 302 (23.1)   63 (23.5) 64 (20.4)   67 (25.8) 81 (26.1)   55 (20.8) 78 (25.7)   40 (22.9) 79 (20.8)  
Sunshine hours /month*, median (p25 − p75) 189 (138–269) 161 (122–225) 210 (159–320) <0.001 156 (101–193) 184 (141–234) <0.001 161 (122–202) 200 (157–251) <0.001 159 (103–200) 201 (150–263) <0.001 252 (162–345) 303 (202–345) 0.031
Clinical characteristics
ESR (mm/h), median (p25 − p75) - - - - 18.0 (9.0–28.0) 16.0 (9.0–30.0) 0.631 10.0 (6.0–23.2) 11.0 (6.0–19.0) 0.691 12.0 (5.0–21.0) 12.0 (6.0–21.0) 0.471 11.0 (5.0–18.0) 10.0 (5.0–18.0) 0.189
CRP (mg/l), median (p25 − p75) - - - - 3.1 (1.4–8.0) 3.0 (1.0–7.3) 0.543 4.1 (1.5–10.6) 3.2 (1.6–7.6) 0.333 3.0 (1.4– 6.1) 2.9 (1.3–6.2) 0.449 2.0 (0.9–4.1) 1.9 (1.0–3.2) 0.358
RF positive, n (%) - - - - 252 (80.3) 264 (75.0) 0.105 - - - - - - - - -
ACPA positive, n (%) - - - - 210 (66.9) 205 (58.2) 0.022 - - - - - - - - -
Erosions, n (%) - - - - 143 (45.5) 169 (48.0) 0.524 - - - 79 (26.8) 92 (27.3) 0.883 - - -
DAS28-ESR, median (p25 − p75) - - - - 3.0 (2.2–3.8) 3.0 (2.3–4.0) 0.937 - - - 2.8 (1.9–3.9) 2.9 (2.0–3.9) 0.807 - - -
HAQ (0–3), median (p25 − p75) - - - - 0.5 (0.1–1.1) 0.6 (0.1–1.2) 0.193 - - - 0.2 (0.0–1.0) 0.3 (0.0–1.9) 0.601 - - -
HLA-B27, n (%) - - - - - - - 218 (74.4) 275 (81.1) 0.042   - - - - -
BASDAI (0–10), median (p25 − p75) - - - - - - - 3.8 (1.8–5.3) 3.3 (1.8–5.0) 0.042 - - - - - -
BASFI (0–10), median (p25 − p75) - - - - - - - 3.7 (1.6–5.8) 2.7 (1.2–4.7) 0.018 - - - - - -
Treatment
Biologic DMARD, n (%) - - - - 123 (39.2) 150 (42.6) 0.367 145 (49.5) 158 (46.6) 0.470 132 (44.7) 142 (42.1) 0.509 - - -
 Vitamin D, n (%) 659 (22.6) 198 (18.3) 392 (27.1) <0.001 120 (38.2) 166 (47.2) 0.020 23 (7.8) 53 (15.6) 0.003 32 (10.8) 68 (20.2) 0.001 23 (12.7) 105 (25.1) <0.001
 Calcium supplements, n (%) 623 (21.4) 191 (17.6) 353 (24.4) <0.001 118 (37.6) 163 (46.3) 0.023 20 (6.8) 42 (12.4) 0.019 33 (11.2) 56 (16.6) 0.050 20 (11.0) 92 (22.0) 0.002
  1. *Hours of sunshine per month considering the period of time between 60 and 90 days prior to the baseline visit (blood test to determine the levels of 25(OH)D was performed at the baseline visit). 25(OH)D 25-hydroxyvitamin D, BMI body mass index, p25 − p75 25th to 75th percentile, ESR erythrocyte sedimentation rate, CRP C-reactive protein, RF rheumatoid factor, ACPA anti-cyclic citrullinated peptide antibodies, DAS28-ESR, disease activity score using 28 joints-erythrocyte sedimentation rate, HAQ (0–3): health assessment questionnaire, HLA-B27 histocompatibility antigen HLA-B27, BASDAI (0–10) Bath ankylosing spondylitis disease activity index, BASFI (0–10) Bath ankylosing spondylitis functional index, DMARD disease-modifying anti-rheumatic drugs