Introduction
Materials and methods
Study population
Data collection
Laboratory measurements
Statistical analyses
Results
Total | CD patients | UC patients | p valuea | |
---|---|---|---|---|
n = 316 | n = 131 | n = 185 | ||
Age, years (SD) | 48.5 (14.8) | 46.5 (14.7) | 49.9 (14.8) | 0.046 |
Women, n (%) | 181 (57.3) | 84 (64.1) | 97 (52.4) | 0.039 |
Postmenopausal state, n (% of women) | 71 (39.2) | 32 (38.1) | 39 (40.2) | NS |
Body mass index, kg/m2 (SD) | 25.3 (4.5) | 25.5 (4.8) | 25.1 (4.3) | NS |
Active IBD, n (%) | 160 (50.6) | 70 (53.4) | 90 (48.6) | NS |
Disease duration IBD, years (SD) | 11.0 (9.7) | 11.1 (10.0) | 11.0 (9.6) | NS |
Exacerbation IBD, episodes/year (SD) | 2.7 (2.1) | 2.8 (2.2) | 2.7 (1.9) | NS |
History of >7.5 mg daily corticosteroid usage for at least 6 months, n (%) | 92 (29.1) | 38 (29.0) | 54 (29.2) | NS |
Daily use of oral vitamin D supplementation, n (%) | 106 (33.5) | 42 (32.1) | 64 (34.6) | NS |
Low dietary calcium intake, n (%) | 15 (4.8) | 6 (4.6) | 9 (4.9) | NS |
Fatty fish intake, units/month (SD) | 2.6 (2.5) | 2.6 (2.3) | 2.7 (2.5) | NS |
Excessive alcohol usage, n (%) | 34 (10.9) | 11 (8.5) | 23 (12.6) | NS |
Current smoking, n (%) | 73 (23.1) | 46 (35.1) | 27 (14.6) | <0.001 |
Preferred exposure to sun when outdoors, n (%) | 166 (53.7) | 61 (36.7) | 105 (63.3) | 0.041 |
Outdoor activities at least 2 h a day | ||||
Summer, days/week (SD) | 4.5 (2.1) | 5.4 (2.1) | 5.4 (2.1) | NS |
Winter, days/week (SD) | 3.0 (2.5) | 3.1 (2.5) | 2.9 (2.4) | NS |
Sun holiday in the last year, n (%) | 138 (44.5) | 49 (37.7) | 89 (49.4) | 0.040 |
Solarium visits, n (%) | 64 (20.6) | 27 (20.8) | 37 (20.6) | NS |
Laboratory markers in serum | ||||
Hb, mmol/L (SD) | 8.6 (0.92) | 8.5 (0.90) | 8.7 (0.93) | NS |
Ht, L/L (SD) | 0.41 (0.04) | 0.40 (0.04) | 0.41 (0.04) | NS |
RDW, % (SD) | 44.6 (4.8) | 45.8 (5.2) | 43.7 (4.2) | <0.001 |
ESR, mm/h (SD) | 14.1 (12.7) | 15.7 (10.8) | 13.0 (13.8) | <0.001 |
CRP, mg/L (SD) | 4.5 (7.7) | 5.1 (6.4) | 4.1 (8.6) | <0.001 |
Calcium, mmol/L (SD) | 2.3 (0.1) | 2.4 (0.1) | 2.3 (0.09) | NS |
Phosphate, mmol/L (SD) | 1.1 (0.2) | 1.1 (0.2) | 1.1 (0.2) | NS |
Albumin, g/L (SD) | 40.6 (3.2) | 40.1 (3.2) | 40.9 (3.2) | 0.006 |
Creatinine, μmol/L (SD) | 72.9 (15.7) | 71.2 (13.7) | 74.2 (16.8) | NS |
TSH, mIU/L (SD) | 1.53 (0.87) | 1.50 (0.95) | 1.54 (0.81) | NS |
Vitamin D deficiency in summer and winter
Vitamin D deficiency <50 nmol/L | Vitamin D adequacy ≥ 50 nmol/L | p valuea | |
---|---|---|---|
n = 122 | n = 194 | ||
Ulcerative colitis, n (%) | 64 (52.2) | 121 (62.4) | 0.08 |
Age, years (SD) | 48.6 (14.7) | 48.5 (14.9) | NS |
Women, n (%) | 62 (50.8) | 119 (61.3) | 0.07 |
Postmenopausal state, n (% of women) | 28 (45.2) | 43 (36.1) | NS |
Body mass index, kg/m2 (SD) | 26.5 (5.3) | 24.4 (3.7) | 0.002 |
Active IBD, n (%) | 67 (54.9) | 93 (47.9) | NS |
Disease duration IBD, years (SD) | 11.3 (10.8) | 10.9 (9.0) | NS |
Exacerbation IBD, episodes/year (SD) | 2.8 (2.1) | 2.7 (2.0) | NS |
History of >7.5 mg daily corticosteroid usage for at least 6 months, n (%) | 42 (34.4) | 50 (25.8) | NS |
Excessive alcohol usage, n (%) | 10 (8.4) | 24 (12.5) | NS |
Sufficient physical activity, n (%) | 67 (54.9) | 93 (47.9) | NS |
Current smoking, n (%) | 17 (13.9) | 56 (28.9) | 0.005 |
Preferred exposure to sun when outdoors, n (%) | 53 (45.3) | 113 (58.9) | 0.020 |
Laboratory markers in serum | |||
Hb, mmol/L (SD) | 8.7 (0.9) | 8.6 (0.9) | NS |
Ht, L/L (SD) | 0.41 (0.04) | 0.41 (0.04) | NS |
RDW, % (SD) | 45.3 (5.6) | 44.2 (4.1) | 0.06 |
ESR, mm/h (SD) | 14.9 (13.4) | 13.7 (12.2) | NS |
CRP, mg/L (SD) | 4.3 (5.7) | 4.7 (8.8) | NS |
Calcium, mmol/L (SD) | 2.4 (0.1) | 2.4 (0.1) | NS |
Phosphate, mmol/L (SD) | 1.1 (0.2) | 1.1 (0.2) | NS |
Alkaline phosphatase, IU/L (SD) | 79.6 (21.9) | 75.2 (31.9) | 0.003 |
Albumin, g/L (SD) | 40.7 (3.0) | 40.5 (3.4) | NS |
Creatinine, μmol/L (SD) | 73.3 (15.5) | 72.7 (15.8) | NS |
TSH, mIU/L (SD) | 1.6 (1.0) | 1.5 (0.8) | NS |
End of summer | End of winter | p valuesa | ||||||
---|---|---|---|---|---|---|---|---|
Total | Vitamin D deficiency <50 nmol/L | Vitamin D adequacy ≥50 nmol/L | Total | Vitamin D deficiency <50 nmol/L | Vitamin D adequacy ≥50 nmol/L | Vitamin D deficiency vs. adequacy | ||
n = 316 | n = 122 | n = 194 | n = 281 | n = 160 | n = 121 | Summer | Winter | |
Oral vitamin D supplementation, n (%) | 106 (33.5) | 32 (26.6) | 74 (38.1) | 117 (43.5) | 53 (34.6) | 64 (55.2) | 0.029 | <0.001 |
Fatty fish intake, units/month (SD) | 2.6 (2.5) | 2.7 (2.8) | 2.5 (2.0) | 2.6 (2.2) | 2.8 (2.4) | 2.5 (2.0) | NS | NS |
Outdoor activities at least 2 h a day, days/week (SD) | 5.4 (2.1) | 5.3 (2.1) | 5.5 (2.1) | 3.0 (2.5) | 3.1 (2.5) | 2.9 (2.5) | NS | NS |
Recent sun holiday, n (%) | 138 (44.5) | 39 (33.1) | 99 (51.6) | 28 (10.1) | 11 (7.0) | 17 (14.3) | <0.001 | 0.047 |
Regular solarium visits, n (%) | 64 (20.6) | 14 (11.9) | 50 (26.0) | 28 (10.1) | 7 (4.5) | 21 (17.6) | 0.003 | 0.012 |
Serum 25OHD level, nmol/L (SD) | 55.1 (16.4) | 39.1 (7.8) | 65.1 (11.8) | 48.4 (20.0) | 35.6 (11.0) | 65.5 (16.0) | – | – |
Vitamin D quartiles
25OHD quartiles, nmol/L | p valuea | ||||
---|---|---|---|---|---|
≤42 nmol/L | 43–53 nmol/L | 54–66 nmol/L | ≥67 nmol/L | ||
n = 79 | n = 78 | n = 81 | n = 78 | ||
Ulcerative colitis, n (%) | 39 (49.4) | 46 (59.0) | 53 (65.4) | 47 (60.3) | NS |
Age, years (SD) | 48.3 (14.3) | 48.9 (14.9) | 50.4 (15.7) | 46.4 (14.3) | NS |
Women, n (%) | 42 (53.2) | 38 (48.7) | 49 (60.5) | 52 (66.7) | NS |
Postmenopausal state, n (% of women) | 20 (47.6) | 13 (34.2) | 20 (40.8) | 18 (34.6) | NS |
Body mass index, kg/m2 (SD) | 26.2 (5.3) | 26.3 (4.8) | 24.5 (3.7) | 24.0 (3.6) | 0.010 |
Active IBD, n (%) | 47 (59.5) | 38 (48.7) | 42 (51.9) | 33 (42.3) | NS |
Disease duration IBD, years (SD) | 11.3 (10.9) | 10.4 (9.5) | 12.2 (9.9) | 10.2 (8.5) | NS |
Exacerbation IBD, episodes/year (SD) | 2.9 (2.2) | 2.8 (1.9) | 2.7 (2.3) | 2.6 (1.9) | NS |
History of >7.5 mg daily corticosteroid usage for at least six months, n (%) | 31 (39.2) | 19 (24.4) | 23 (28.4) | 19 (24.4) | NS |
Daily use of oral vitamin D supplementation, n (%) | 22 (27.8) | 21 (26.9) | 36 (44.4) | 27 (34.6) | 0.07 |
Low dietary calcium intake, n (%) | 3 (3.8) | 5 (6.4) | 5 (6.2) | 2 (2.6) | NS |
Fatty fish intake, units/month (SD) | 2.2 (2.0) | 3.4 (3.2) | 2.6 (2.0) | 2.4 (2.4) | 0.05 |
Excessive alcohol usage, n (%) | 6 (7.8) | 8 (10.4) | 10 (12.3) | 10 (13.2) | NS |
Current smoking, n (%) | 8 (10.1) | 19 (24.4) | 22 (27.2) | 24 (30.8) | 0.009 |
Preferred exposure to sun when outdoors, n (%) | 29 (37.7) | 43 (57.3) | 38 (47.5) | 56 (72.7) | 0.003 |
Outdoor activities at least two hours a day, days/week (SD) | 5.1 (2.3) | 5.5 (1.9) | 5.6 (2.1) | 5.4 (2.3) | NS |
Sufficient physical activity, n (%) | 66 (83.5) | 73 (93.6) | 68 (84.0) | 73 (93.6) | 0.06 |
Sun holiday in the last year, n (%) | 26 (33.3) | 23 (30.7) | 40 (50.0) | 49 (63.3) | <0.001 |
Solarium visits, n (%) | 9 (11.5) | 13 (17.3) | 18 (22.5) | 24 (31.2) | 0.020 |
Laboratory markers in serum | |||||
Hb, mmol/L (SD) | 8.6 (1.0) | 8.7 (0.9) | 8.6 (1.0) | 8.6 (0.8) | NS |
Ht, L/L (SD) | 0.41 (0.04) | 0.41 (0.03) | 0.41 (0.04) | 0.40 (0.03) | NS |
RDW, % (SD) | 45.5 (5.5) | 44.1 (4.8) | 44.7 (4.5) | 44.0 (3.9) | NS |
ESR, mm/h (SD) | 16.3 (15.5) | 14.3 (12.1) | 13.9 (13.6) | 12.0 (8.3) | NS |
CRP, mg/L (SD) | 4.6 (5.7) | 4.6 (7.5) | 4.4 (10.5) | 4.6 (6.3) | NS |
Calcium, mmol/L (SD) | 2.4 (0.1) | 2.3 (0.1) | 2.4 (0.1) | 2.3 (0.1) | NS |
Phosphate, mmol/L (SD) | 1.1 (0.2) | 1.1 (0.1) | 1.1 (0.2) | 1.1 (0.2) | NS |
Alkaline phosphatase, IU/L (SD) | 79.1 (20.0) | 82.4 (39.6) | 71.4 (23.3) | 74.9 (26.5) | 0.022 |
Albumin, g/L (SD) | 40.7 (3.2) | 40.4 (3.3) | 40.4 (3.2) | 40.7 (3.3) | NS |
Creatinine, μmol/L (SD) | 72.1 (15.4) | 75.9 (15.7) | 74.2 (17.2) | 69.3 (13.6) | 0.08 |
TSH, mIU/L (SD) | 1.5 (0.8) | 1.7 (1.0) | 1.4 (0.6) | 1.5 (0.9) | NS |
Multivariate analyses
Odds ratio (95% CI) | ||
---|---|---|
Summera
| Winterb
| |
Age | 0.97 (0.95–1.00) | 0.99 (0.97–1.01) |
Female gender | 0.59 (0.34–1.03) | 0.78 (0.45–1.38) |
Ulcerative colitis | 0.55 (0.31–0.95) | 0.91 (0.53–1.56) |
Active IBD | 1.50 (0.87–2.57) | –c
|
Body mass index | 1.11 (1.05–1.19) | –c
|
Current smoking | 0.27 (0.13–0.57) | –c
|
Alkaline phosphatase | 1.00 (0.99–1.01) | –c
|
Preferred exposure to sun when outdoors | 0.81 (0.47–1.41) | –c
|
Oral vitamin D supplementation | 0.52 (0.29–0.94) | 0.44 (0.26–0.75) |
Recent sun holiday | 0.42 (0.24–0.74) | 0.48 (0.20–1.14) |
Regular solarium visits | 0.28 (0.13–0.63) | 0.17 (0.06–0.50) |
Fatty fish intake | 0.99 (0.89–1.10) | 1.05 (0.93–1.18) |
Outdoor activities at least 2 h a day | 0.97 (0.86–1.10) | 1.01 (0.91–1.13) |