Table 1.
Characteristics of the study population (n=30 023) and average serum 25(OH)D levels
| N (%) | Mean 25(OH)D (SEM) | |
| Total population | 30 023 (100%) | 69.9 (0.19) |
| Sex | ||
| Female | 18 688 (62.3%) | 72.1 (0.25) |
| Male | 11 302 (37.6%) | 66.0 (0.30) |
| Age group | ||
| 20–29 | 3099 (10.3%) | 63.3 (0.55) |
| 30–39 | 3721 (12.4%) | 66.3 (0.56) |
| 40–49 | 3570 (11.9%) | 66.6 (0.57) |
| 50–59 | 4131 (13.8%) | 69.5 (0.53) |
| 60–69 | 4277 (14.2%) | 71.7 (0.49) |
| >70 | 11 225 (37.4%) | 73.2 (0.31) |
| Medical specialty | ||
| AMU | 1690 (5.6%) | 69.0 (0.81) |
| BOE | 1053 (3.5%) | 71.2 (0.92) |
| EMER | 1656 (5.5%) | 69.6 (0.86) |
| ENDO | 1229 (4.1%) | 74.0 (0.90) |
| GAST | 1574 (5.2%) | 66.9 (0.79) |
| NEPH | 1261 (4.2%) | 64.1 (0.80) |
| NEUR | 654 (2.2%) | 76.8 (1.66) |
| ORTH | 1080 (3.6%) | 67.9 (0.89) |
| OTHER | 14 214 (47.3%) | 68.0 (0.27) |
| PRIV | 5612 (18.7%) | 75.5 (0.47) |
| Season of measurement | ||
| Summer (Dec–Feb) | 5588 (18.6%) | 76.1 (0.43) |
| Autumn (Mar–May) | 8366 (27.9%) | 74.0 (0.36) |
| Winter (Jun–Aug) | 8320 (27.7%) | 64.9 (0.36) |
| Spring (Sep–Nov) | 7749 (25.8%) | 66.2 (0.37) |
| Year of measurement | ||
| 2014 | 8063 (26.9%) | 71.5 (0.37) |
| 2015 | 7620 (25.3%) | 71.3 (0.38) |
| 2016 | 7401 (24.7%) | 68.6 (0.39) |
| 2017 | 6939 (23.1%) | 67.7 (0.39) |
| Vitamin D supplementation | ||
| Yes | 2588 (8.6%) | 80.4 (0.61) |
| No information | 27 435 (91.4%) | 68.9 (0.20) |
Specialties with <1000 patients (except for NEUR) were placed into OTHER for analysis.
AMU, acute medical unit; BOE, breast/oncology/endocrine surgery; EMER, emergency; ENDO, endocrinology; GAST, gastroenterology; NEPH, nephrology; NEUR, neurology; ORTH, orthopaedic; PRIV, private.