Table 2. Serum levels of 25(OH)D in ng/mL, mean±sd, for different potential explanatory variables by subject category.
| COPD | p** | Controls | p** | |
| 25(OH)D, ng/mL | 25.2±10.0 | 25.0±9.5 | ||
| Sex | 0.58 | 0.42 | ||
| Women | 25.6±10.4 | 25.5±9.4 | ||
| Men | 24.9±9.8 | 24.6±9.5 | ||
| Age | 0.10 | <0.001 | ||
| 40–54 | 22.5±10.2 | 20.4±7.9 | ||
| 55–64 | 25.0±10.4 | 27.6±9.4 | ||
| >65 | 26±9.4 | 28.3±9.0 | ||
| Smoking habits | <0.01 | <0.01 | ||
| Never | 25.9±8.3 | |||
| Ex | 26.3±9.9 | 27.5±9.0 | ||
| Current | 23.6±9.9 | 23.4±9.7 | ||
| BMI * (kg/m2) | 0.001 | 0.22 | ||
| <18.5 | 21.6±10.0 | 28.4±0.0 | ||
| 18.5–24.9 | 26.0±10.2 | 25.9±9.4 | ||
| 25–30 | 26.5±9.4 | 25.0±9.4 | ||
| >30 | 21.6±9.7 | 22.6±10.1 | ||
| Comorbidity, Charlsons score | 0.94 | 0.31 | ||
| <2 | 25.1±10.1 | 24.9±9.4 | ||
| ≥2 | 25.1±9.9 | 27.0±10.4 | ||
| Depression, CES-D score≥16 | <0.01 | |||
| Yes | 22.0±10.3 | |||
| No | 26.0±9.9 | |||
| Season | <0.001 | <0.001 | ||
| Winter | 20.9±9.8 | 22.0±8.9 | ||
| Spring | 22.7±9.6 | 23.7±9.4 | ||
| Summer | 27.8±9.4 | 32.0±7.3 | ||
| Autumn | 20.6±9.5 | 30.2±8.1 | ||
| GOLD status: | <0.001 | |||
| II (FEV1 50–80) | 28.1±9.8 | |||
| III (FEV1 30–50) | 22.7±9.3 | |||
| IV (FEV1 0–30) | 21.6±10.0 | |||
| Hypoxaemia (resting PaO2 § <8.0) | <0.01 | |||
| Yes | 20.5±8.1 | |||
| No | 25.9±10.0 | |||
| Not measured | 24.0±10.7 | |||
| Cough with phlegm | 0.22 | |||
| Yes | 24.6±10.2 | |||
| No | 25.±9.7 | |||
| Dyspnea (grade III) | 0.01 | |||
| Yes | 23.7±9.6 | |||
| No | 26.3±10.1 | |||
| Inhaled steroids, ICS | 0.05 | |||
| Yes | 24.5±10.1 | |||
| No | 26.5±9.5 | |||
| Exacerbations # : | 0.18 | |||
| <2 last 12 months | 25.4±9.9 | |||
| ≥2 last 12 months | 23.7±10.5 | |||
| Treatment for osteoporosis | 0.33 | |||
| Yes | 27.9±10.9 | |||
| No | 25.0±10.0 |
*
BMI: body mass index.
#
Exacerbations requiring either hospitalisation or treatment with oral antibiotics or oral steroids.
§
PaO2: arterial oxygen tension.
**
Associations were tested with t-test and ANOVA.