TABLE 1.
Characteristics of participants from the UK Biobank.
| Covariate | Total (N = 429,681) | Psoriasis (N = 2,856) | No Psoriasis (N = 426,825) | p b |
| Age at baseline (years), mean (SD) | 56.50 (8.12) | 57.17 (7.93) | 56.49 (8.12) | <0.001 |
| Age category (years), N (%) | <0.001 | |||
| <50 | 101,816 (23.7) | 569 (19.9) | 101,247 (23.7) | |
| 50–59 | 142,255 (33.1) | 969 (33.9) | 141,286 (33.1) | |
| > 60 | 185,610 (43.2) | 1,318 (6.1) | 184,292 (43.2) | |
| Sex, N (%) | 0.137 | |||
| Female | 230,896 (53.7) | 1,495 (52.3) | 229,401 (53.7) | |
| Male | 198,785 (46.3) | 1,361 (47.7) | 197,424 (46.3) | |
| Average total household income before tax (€), N (%) | <0.001 | |||
| Less than 18,000 | 82,199 (19.1) | 689 (24.1) | 81,510 (19.1) | |
| 18,000–30,999 | 93,161 (21.7) | 630 (22.1) | 92,531 (21.7) | |
| 31,000–51,999 | 96,226 (22.4) | 588 (20.6) | 95,638 (22.4) | |
| 52,000–100,000 | 75,872 (17.7) | 433 (15.2) | 75,439 (17.7) | |
| Greater than 100,000 | 20,262 (4.7) | 95 (3.3) | 20,167 (4.7) | |
| Unknown | 61,961 (14.4) | 421 (14.7) | 61,540 (14.4) | |
| Education, N (%) | <0.001 | |||
| College or university degree | 139,999 (32.6) | 824 (28.9) | 139,175 (32.6) | |
| Professional qualifications | 50,538 (11.8) | 359 (12.6) | 50,179 (11.8) | |
| A Levels/AS levels or equivalent | 47,823 (11.1) | 265 (9.3) | 47,558 (11.2) | |
| O Levels/GCSEs or equivalent | 113,917 (26.5) | 748 (26.2) | 113,169 (26.5) | |
| None of the above | 76,980 (17.9) | 657 (23.0) | 76,323 (17.9) | |
| Smoking status, N (%) | <0.001 | |||
| Never | 235,288 (54.8) | 1,253 (43.9) | 234,035 (54.9) | |
| Previous | 148,358 (34.6) | 1,114 (39.0) | 147,244 (34.5) | |
| Current | 43,925 (10.2) | 473 (16.6) | 43,452 (10.2) | |
| Unknown | 1,683 (0.4) | 13 (0.5) | 1,670 (0.4) | |
| BMI (kg/m2), mean (SD) | 27.40 (4.78) | 28.37 (5.24) | 27.39 (4.77) | <0.001 |
| BMI category, N (%) | <0.001 | |||
| Normal (<25) | 142,528 (33.3) | 744 (26.1) | 141,784 (33.3) | |
| Overweight (25∼30) | 181,802 (42.5) | 1,234 (43.3) | 180,568 (42.5) | |
| Obesity (> 30) | 103,731 (24.2) | 869 (30.5) | 102,862 (24.2) | |
| Vitamin D concentrations (nmol/L), Mean (SD) | 48.26 (19.69) | 46.68 (20.04) | 48.27 (19.69) | <0.001 |
| Vitamin D concentrations (nmol/L)a, N (%) | <0.001 | |||
| 12.7–32.6 | 106,657 (24.8) | 812 (28.4) | 105,845 (24.8) | |
| 32.6–46.8 | 107,675 (25.1) | 703 (24.6) | 106,972 (25.1) | |
| 46.8–62.0 | 107,454 (25.0) | 697 (24.4) | 106,757 (25.0) | |
| 62.0–104.0 | 107,895 (25.1) | 644 (22.5) | 107,251 (25.1) | |
| Vitamin D category (nmol/L), N (%) | <0.001 | |||
| Deficient (<25) | 54,306 (12.7) | 460 (16.1) | 54,306 (12.7) | |
| Insufficient (25∼50) | 183,631 (42.7) | 1,210 (42.4) | 182,421 (42.7) | |
| Optimal (> 50) | 191,284 (44.6) | 1,168 (41.5) | 190,098 (44.6) | |
| Vitamin D supplements, N (%) | 0.197 | |||
| No | 421,883 (98.2) | 2,795 (97.9) | 419,088 (98.2) | |
| Yes | 7,798 (1.8) | 61 (2.1) | 7,737 (1.8) |
aThe data were divided by quartiles.
bContinuous data was presented as mean ± standard deviation, and between-group difference was tested using analysis of variance. Categorical data were presented as number (%), and the between-group difference was tested using chi-squared test. p < 0.05 was considered statistically significant for all tests.