Univariate analysis of variance comparing mean 25-OHD serum levels according to the different genotypes of the vitamin D-binding gene (GC)
| rs Number | Genotype | Subjects, n (%) | Serum 25-OHD mean±SD | p Value | |
| COPD | rs7041 | GG | 85 (34) | 22.1±7.8 | Reference |
| GT | 108 (43) | 20.0±7.0 | 0.12 | ||
| TT | 60 (23) | 16.7±7.2 | <0.0001 | ||
| rs4588 | CC | 128 (51) | 21.0±7.9 | Reference | |
| CA | 109 (43) | 19.2±7.0 | 0.15 | ||
| AA | 16 (6) | 15.6±7.2 | 0.01 | ||
| Controls | rs7041 | GG | 54 (36) | 26.3±8.7 | Reference |
| GT | 73 (49) | 24.6±9.1 | 0.5 | ||
| TT | 23 (15) | 20.9±5.0 | 0.03 | ||
| rs4588 | CC | 88 (59) | 25.8±8.8 | Reference | |
| CA | 49 (33) | 23.8±8.6 | 0.09 | ||
| AA | 13 (8) | 20.6±4.6 | 0.09 |
Univariate analysis of variance (ANOVA) with a Tukey–Kramer posthoc test was performed to calculate the mean 25-hydroxyvitamin D (25-OHD) serum levels (ng/ml) stratified according to rs7041 and rs4588 genotypes in patients with chronic obstructive pulmonary disease (COPD) (n=253) and controls (n=150). p Values indicate significance of the genotypes relative to wild-type genotypes.