. 2022 Mar 24;6(5):e10619. doi: 10.1002/jbm4.10619

Table 1.

Participants' Characteristics and Response to Vitamin D Supplementation ^a

n	Baseline	12 months (12,000 IU)	12 months (24,000 IU)	12 months (48,000 IU)	ANCOVA ^b analysis
n	379	122	124	126	ANCOVA ^b analysis
Age (years)	74.1 [71.5–77.0]	75.6 [72.5–77.3]	76.0 [72.5–77.9]	76.4 (4.4)	n/a
Plasma calcium and renal function markers
Albumin (g/L)	45.7 (2.2)	44.6 (2.1)*	44.5 (2.6)*	44.3 (2.0)*	0.70
Adjusted calcium (mmol/L)	2.2 (0.1)	2.3 (0.1)	2.2 (0.1)	2.2 (0.1)	0.07
Phosphate (mmol/L)	0.88 (0.18)	0.79 (0.19)*	0.81 (0.17)*	0.81 (0.19)*	0.68
Cystatin C (mg/L)	0.87 (0.22)	0.88 (0.27)	0.92 (0.25)*	0.95 (0.29)*	0.41
Creatinine (μmol/L)	82.1 (19.1)	82.5 [67–94]*	84.6 [71–96]*	78.1 (66–88]*	0.25
eGFR (mL/min per 1.73 m²)	72 (15)	73 (14)	74 (16)	70 (15)	0.54
Klotho (pg/mL)	493.7 [392.6–627.7]	502.0 [403.1–639.6]	502.7 [395.5–611.2]	477.6 [399.6–589.2]	<0.001
cFGF23 (RU/mL)	66.7 [54.9–84.2]	90.8 [65.3–104.9]*	85.7 [59.7–94.9]*	77.8 [58.4–87.3]*	0.11
iFGF23 (pg/mL)	55.1 [44.5–72.7]	66.9 [42.5–88.4]*	71.7 [54.5–79.4]*	73.2 [52.2–84.7]*	0.80
iFGF23/cFGF23	1.9 [1.5–2.5]	2.1 [1.4–2.2]	2.2 [1.4–2.3]	2.3 [1.4–2.3]	0.75
Vitamin D metabolism markers
Total 25(OH)D (nmol/L)	40.0 (20.1)	55.9 (15.6)*	64.6 (15.3)*	79.0 (15.1)*	<0.001
Free 25(OH)D (pmol/L)	8.4 (4.3)	11.7 (3.3)*	13.8 (3.4)*	16.9 (4.3)*	<0.001
24,25(OH)₂D (nmol/L)	3.2 [2.0–5.5]	6.1 (2.7)*	7.4 (2.8)*	9.4 (3.0)*	<0.001
25(OH)D/24,25(OH)₂D	14.5 [11.3–18.8]	12.1 [9.4–12.9]*	11.9 [10.0–13.4]*	12.9 (4.7)*	<0.001
1,25(OH)₂D (pmol/L)	94.5 (29.0)	100.6 (29.8)	101.0 (29.4)*	101.9 (30.8)*	0.099
1,25(OH)₂D/24,25(OH)₂D	25.7 [16.8–44.4]	17.7 [11.9–21.8]	14.6 [8.9–18.7]	15.3 [9.0–18.2]	<0.001
DBP (mg/L)	367.8 (63.4)	362.5 (74.1)	356.9 (46.1)	384.4 (57.8)*	<0.01
PTH (pg/mL)	43.4 [33.2–57.4]	39.8 [28.8–53.5]*	40.9 [26.3–55.5]*	37.3 [27.8–47.5]*	<0.01
Wnt signaling pathway markers
SOST (pmol/L)	44.3 [32.4–60.0]	46.9 [32.6–63.5]	45.4 [32.1–57.8]	46.5 [33.2–61.2]	0.20
DKK1 (pmol/L)	31.2 (16.5)	40.6 (17.9)*	33.2 (19.0)	38.9 (18.1)*	0.87
OPG (pmol/L)	5.67 (2.08)	5.69 (2.04)	5.12 [4.25–6.47]	5.89 (2.17)	0.20
sRANKL (pmol/L)	0.12 [0.08–0.18]	0.14 [0.08–0.18]	0.13 [0.07–0.18]	0.14 (0.07)	0.75
sRANKL/OPG	0.02 [0.01–0.04]	0.03 [0.01–0.03]	0.04 [0.01–0.04]	0.03 [0.01–0.04]	0.85
Bone mineral density and metabolism
Hip BMD (g/m²)	0.98 (0.17)	0.96 (0.15)	0.98 (0.16)	0.99 (0.18)	0.19
Hip BMC (g)	35.44 (8.30)	34.08 (7.56)	35.42 (7.92)	35.73 (8.63)	0.14
FN BMD (g/m²)	0.902 (0.152)	0.88 (0.13)	0.90 (0.14)	0.92 (0.15)	0.13
FN BMC (g)	4.90 (1.09)	4.78 (0.96)	4.82 (1.04)	4.70 (1.16)	0.72
BAP (μg/L)	9.5 [7.9–12.3]	11.4 [8.4–13.8]*	10.7 [7.7–12.7]	11.4 [8.0–14.1]	0.87
CTX (ng/mL)	0.40 [0.30–0.50]	0.36 (0.16)	0.37 (0.15)	0.35 (0.14)	0.48
PINP (μg/L)	36.2 [28.8–46.2]	40.1 [31.7–52.6]	39.1 [31.0–46.6]*	38.4 [28.9–47.1]*	0.53
PINP/CTX	101.4 [85.9–116.9]	120.5 [103.6–155.2]*	124.0 [107.6–158.5]*	118.8 [100.8–157.1]*	0.99

1,25(OH)₂D = 1,25‐dihydroxy vitamin D; 24,25(OH)₂D = 24,25‐dihydroxy vitamin D; 25(OH)D = 25‐hydroxy vitamin D; BAP = bone‐specific alkaline phosphatase; BMC = bone mineral content; BMD = bone mineral density; cFGF23 and iFGF23 = c‐terminal and intact fibroblast growth factor‐23, respectively; CTX = C‐terminal telopeptide; DBP = vitamin D binding protein; DKK1 = Dickkopf‐related protein 1; eGFR = estimated glomerular filtration rate; FN = femoral neck; OPG = osteoprotegerin; PINP = procollagen 1 intact N‐terminal; PTH = parathyroid hormone; SOST = sclerostin; sRANKL = soluble receptor activator of NF‐κB ligand.

^{^a}

For normally distributed data, results are expressed as mean (SD); skewed results are expressed as median [interquartile range].

^{^b}

ANCOVA was used to test between‐group differences after 12 months of supplementation, with the baseline value as a covariate.

*Denotes significantly different from baseline p < 0.05. Paired t tests were used to analyze pre‐ and post‐supplementation values for each supplementation group.