Research Article
Vitamin D Binding Protein Affects the Correlation of 25(OH)D and Frailty in the Older Men
Table 1
Elected baseline characteristics across quartiles of vitamin D binding protein (medians or proportions).
| | Characteristic | Quartile of serum vitamin D binding protein (nmol/L) | value | Q1
<4046 | Q2
4046–<5269 | Q3
5269–<6686 | Q4
6686 |
| | Age (years) | 76.5 | 75.1 | 76.8 | 77.3 | Matched | | Height (cm) | 170 | 169 | 171 | 172 | 0.89 | | Weight (kg) | 74.5 | 78.2 | 76.1 | 77.2 | 0.43 | | BMI (kg/m2) | 24.6 | 25.1 | 24.2 | 25.5 | 0.61 | | Education (% > elementary) | 16.0 | 14.6 | 14.1 | 13.8 | 0.49 | | Physically active during leisure time (% yes) | 18.5 | 16.9 | 22.1 | 23.3 | 0.21 | | Season of blood draw (% Nov.–Mar.) | 100 | 100 | 100 | 100 | Matched | | Supplemental vitamin D use (% yes) | 28.1 | 26.7 | 15.3 | 14.6 | 0.16 | | Supplemental calcium use (% yes) | 29.7 | 30.0 | 23.3 | 20.1 | 0.23 | | Serum biomarkers | | | | | | | 25(OH)D (nmol/L) | 46.1 | 42.5 | 41.2 | 45.6 | 0.27 | | DBP (nmol/L) | 3642 | 4632 | 5861 | 7183 | NA | | Free 25(OH)D (pmol/L) | 26.5 | 28.4 | 23.9 | 22.2 | 0.13 | | Albumin (g/L) (normal range: 40–55 g/L) | 36.0 | 37.7 | 38.3 | 39.1 | 0.36 | | Serum calcium (mmol/L) (normal range: 2.03–2.54 mmol/L) | 2.1 | 2.2 | 2.1 | 2.3 | 0.46 | | Parathyroid hormone (ng/L) (normal range: 20.3–46.8 ng/L) | 26.6 | 30.1 | 27.9 | 29.1 | 0.29 |
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BMI: body mass index; 25(OH)D: 25-hydroxyvitamin D; DBP: vitamin D binding protein.
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