Article Figures & Data
Figures
- Figure 1.
Latitudes of study sites. 1: Salt Lake City, UT; 2: Denver, CO; 3: Omaha, NE; 4: Dallas, TX; 5: Jackson, MI; 6: Washington, DC. Area above the dashed line and below the dotted line has insufficient sun exposure for cutaneous vitamin D synthesis from November through February23. Area below dashed line allows for cutaneous production of vitamin D throughout the year28.
- Figure 2.
Proportions of patients with RA with 25(OH) vitamin D insufficiency and deficiency (showing 95% confidence intervals), by patients’ characteristics.
Tables
- Table 1.
Patient characteristics among US veterans with RA: total study population and presence/absence of 25 (OH)-vitamin D insufficiency (< 30 ng/ml; 75 nmol/l); data are percentage or mean (SD).
Characteristic Total RA Population, n = 850 With Vitamin D Insufficiency, n = 715 Without Vitamin D Insufficiency, n = 135 p Sociodemographic and health measures Age, yrs 64.0 (11.3) 63.6 (11.2) 66.3 (11.4) 0.009 Caucasian race/ethnicity 76 74 84 0.017 Men 90 90 93 0.201 High school education or greater 83 82 86 0.338 Ever smoking 80 81 77 0.328 Body Mass Index, kg/m2 27.9 (5.7) 28.1 (5.8) 26.6 (5.2) 0.006 Comorbidity count (0–8) 2.0 (1.4) 2.0 (1.4) 1.8 (1.3) 0.187 Season of enrollment Summer 24 23 27 0.775 Fall 20 20 19 Winter 25 25 24 Spring 31 31 30 RA-related measures Anti-CCP antibody-positive, % 76 78 67 0.009 RF-positive, % 81 81 78 0.388 Nodules, % 39 39 36 0.511 Radiographic changes, % 53 53 52 0.852 Pain (0–10) 4.8 (3.0) 4.8 (3.0) 4.6 (3.0) 0.412 MD-HAQ (0–3) 1.0 (0.6) 1.0 (0.6) 1.0 (0.6) 0.698 Tender joint count (0–28) 5.6 (7.1) 5.7 (7.2) 4.8 (6.4) 0.186 Swollen joint count (0–28) 4.5 (5.6) 4.5 (5.7) 4.4 (5.1) 0.923 Disease Activity Score-28 4.1 (1.6) 4.1 (1.6) 4.1 (1.5) 0.999 Patient global well-being (0–100mm) 44.6 (26.7) 44.5 (26.8) 45.1 (26.3) 0.814 hs-CRP, mg/l 13.2 (19.5) 13.1 (19.9) 13.5 (17.7) 0.840 ESR, mm/h 27.7 (23.6) 27.9 (24.0) 26.9 (21.4) 0.660 Duration of RA at enrollment, yrs 12.4 (11.5) 12.4 (11.6) 12.9 (11.2) 0.660 Medication use, % DMARD 90 90 92 0.453 Methotrexate 54 54 57 0.462 Biologic 32 30 35 0.352 Prednisone 48 48 47 0.903 Vitamin D supplementation* 34 32 47 < 0.001 -
↵* Vitamin D use included vitamin D supplements (2.3%), cholecalciferol (0.5%), combination of calcium and vitamin D supplements (24.2%), or patient-reported supplementation from VARA database (16.3%). Anti-CCP: anti-cyclic citrullinated peptide antibody; RF: rheumatoid factor; MD-HAQ: Multidimensional Health Assessment Questionnaire; hs-CRP: high sensitivity C-reactive protein; ESR: erythrocyte sedimentation rate; DMARD: disease modifying antirheumatic drugs.
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- Table 2.
Multivariate associations of patient characteristics with the presence of 25 (OH) vitamin D insufficiency and deficiency in US veterans with rheumatoid arthritis. Associations examined using backwards stepwise regression with age, sex, season, and race/ethnicity forced into the model; variables with p value < 0.1 entered and p value < 0.05 required to remain in final model; variables entered and then removed from model for vitamin D sufficiency included RF positivity and comorbidity count; variables entered and then removed from model examining vitamin D deficiency included swollen joint count and smoking status.
Characteristic Insufficiency Deficiency OR (95% CI) p OR (95% CI) p Age, yrs 0.99 (0.98 to 1.00) 0.141 0.99 (0.98 to 1.00) 0.140 Male sex 0.95 (0.63 to 1.43) 0.820 0.80 (0.56 to 1.13) 0.207 Season Winter Referent — Referent — Summer 0.83 (0.63 to 1.10) 0.187 0.83 (0.67 to 1.03) 0.084 Fall 0.89 (0.46 to 1.72) 0.731 0.80 (0.40 to 1.64) 0.548 Spring 1.00 (0.75 to 1.33) 0.998 1.28 (1.06 to 1.55) 0.011 Caucasian race/ethnicity 0.62 (0.46 to 0.84) 0.002 0.41 (0.33 to 0.51) < 0.001 Anti-CCP antibody positivity 2.00 (1.63 to 2.45) < 0.001 1.55 (1.18 to 2.05) 0.002 Vitamin D supplementation 0.54 (0.34 to 0.87) 0.011 0.47 (0.35 to 0.62) < 0.001 CRP, mg/l — — 0.99 (0.99 to 1.00) 0.008 Tender joint count (0–28) — — 1.02 (1.01 to 1.04) 0.001 -
Anti-CCP: anti-cyclic citrullinated peptide antibody; CRP: C-reactive protein.
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