Table 2. Different forms of vitamin D levels in the current cohort.
| Median | IQR | p-value* | |
|---|---|---|---|
| Vitamin D binding protein (μg/ml) | 236.0 | 174.4–280.0 | |
| 25-OH-D | |||
| Total form (ng/ml) | 17.7 | 11.6–23.4 | 0.87 |
| Users | 18.2 | 11.9–22.4 | |
| Non-users | 17.2 | 10.6–24.1 | |
| Bioavailable form (ng/ml) | 2.1 | 1.5–3.0 | 0.92 |
| Users | 2.0 | 1.5–3.0 | |
| Non-users | 2.1 | 1.4–3.2 | |
| 1,25-(OH)2-D | |||
| Total form (pg/ml) | 17.6 | 11.1–26.9 | <0.01 |
| Users | 18.9 | 11.1–41.2 | |
| Non-users | 15.7 | 9.4–21.1 | |
| Bioavailable form (pg/ml) | 3.6 | 2.1–5.5 | <0.01 |
| Users | 4.0 | 2.2–8.1 | |
| Non-users | 3.1 | 1.7–3.9 | |
Formulae for calculation were adapted from Vermeulen equations (J Clin Endocrinol Metab 1999;84:3666-72) originally and later affirmed in vitamin D forms determination with consistent results (reference 21).
*Comparison between active vitamin D users and non-users.
Abbreviations: IQR, inter-quartile range.