Table 1.
Subject characteristics and vitamin D parameters.
Table 2.
Distribution of vitamin D biomarkers according to sex and age, excluding seven subjects with PTH > 65 pg/mL.
Fig 1.
Relationship of 25-hydroxy vitamin D with 24,25-dihydroxyvitamin D and vitamin D metabolite ratio.
(A) Association between 25(OH)D and 24,25(OH)2D. Circles represent females, and triangles represent males; different colors represent different age groups. Dashed lines represent linear fit generated using ordinary linear regression with the slopes adjusted for subjects in the age group 18–34 years (red) or 65–78 years (blue). Linear regression was performed using all subjects, but subjects with 25(OH)D above 60 ng/mL were truncated for presentation. (B) Association between 25(OH)D and VMR. Circles represent females, and triangles represent males; different colors represent different age groups. Dashed lines indicate VMR values calculated from the corresponding 24,25(OH)2D and 25(OH)D concentrations according to the linear regression between 25(OH)D and 24,25(OH)2D. 25(OH)D: 25-hyroxyvitamin D; 24,25(OH)2D: 24,25-dihydroxyvitamin D; VMR: vitamin D metabolite ratio.
Fig 2.
Relationship of bioavailable 25-hydroxyvitamin D with 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and vitamin D metabolite ratio.
(A) Association between bioavailable 25(OH)D and 25(OH)D. (B) Association between bioavailable 25(OH)D and 24,25(OH)2D. (C) Association between bioavailable 25(OH)D and VMR. Dashed lines represent linear fit generated using ordinary linear regression. 25(OH)D: 25-hyroxyvitamin D; 24,25(OH)2D: 24,25-dihydroxyvitamin D; VMR: vitamin D metabolite ratio.
Fig 3.
Relationship of parathyroid hormone with vitamin D parameters.
Association of PTH with (A) 25(OH)D, (B) 24,25(OH)2D, (C) VMR, and (D) bioavailable 25(OH)D. PTH was log-transformed. Dashed lines represent linear fit generated using ordinary linear regression. PTH: parathyroid hormone; 25(OH)D: 25-hyroxyvitamin D; 24,25(OH)2D: 24,25-dihydroxyvitamin D; VMR: vitamin D metabolite ratio.