Effects of Vitamin D Supplementation on Glucose and Insulin Homeostasis and Incident Diabetes among Nondiabetic Adults: A Meta-Analysis of Randomized Controlled Trials
Table 1
Meta-analysis of vitamin D supplementation on indices of glucose and insulin homeostasis stratified by dose.
Outcomes
Overall
≤1000 IU/d
>1000 and ≤4000 IU/d
>4000 IU/d
for trend
/
WMD
(%)
/
WMD
(%)
/
WMD
(%)
/
WMD
(%)
25 (OH) D
46/4992
40.14 (37.07, 43.22)
97.8
13/1661
31.16 (27.63, 34.09)
97.4
15/1603
39.64 (35.47, 43.82)
89.2
18/1728
47.34 (37.85, 56.84)
97.8
0.02
HbA1c
16/2298
−0.04 (−0.07, 0.00)
86.2
4/527
−0.07 (−0.16, 0.01)
88.7
7/1159
0.01 (−0.05, 0.07)
83.9
5/612
−0.11 (−0.26, 0.05)
84.1
0.97
Fasting glucose
40/5509
−0.11 (−0.17, −0.04)
96.1
12/2506
−0.08 (−0.18, 0.02)
97.8
14/1581
−0.08 (−0.14, −0.02)
46.9
14/1480
−0.16 (−0.38, 0.06)
94.5
0.42
Insulin
32/4740
−1.47 (−2.00, −0.95)
90.8
10/2192
−0.89 (−1.83, 0.05)
94.5
12/1381
−0.94 (−1.98, 0.11)
51.7
10/1167
−3.03 (−5.29, −0.76)
81.1
0.08
2 h glucose
15/1929
−0.06 (−0.47, 0.35)
88.4
3/171
0.13 (−0.21, 0.46)
0
8/1182
0.08 (−0.60, 0.77)
91.9
4/576
−0.47 (−1.34, 0.39)
89.3
0.24
2 h insulin
5/1379
−2.17 (−15.60, 11.25)
93.4
NA
NA
NA
3/870
5.70 (4.92, 6.47)
0
2/509
−13.29 (−39.69, 13.11)
94.0
0.17
Insulin sensitivity
QUICKI
12/1740
0.00 (−0.00, 0.01)
72.1
1/123
−0.02 (−0.05, 0.01)
NA
4/919
0.00 (−0.00, 0.01)
75.2
7/698
0.01 (−0.00, 0.01)
73.9
0.55
HOMA-IR
36/5484
−0.32 (−0.47, −0.17)
96.1
13/2867
−0.24 (−0.50, 0.02)
97.0
9/1178
−0.22 (−0.54, 0.10)
67.3
14/1439
−0.45 (−0.90, −0.01)
95.9
0.34
HOMA2-IR
5/353
−0.14 (−0.31, 0.04)
46.6
NA
NA
NA
3/178
−0.21 (−0.46, 0.04)
42.1
2/175
−0.05 (−0.26, 0.16)
33.2
0.43
HOMA2-%S
5/329
0.57 (−3.24, 4.37)
22.6
NA
NA
NA
5/329
0.57 (−3.24, 4.37)
22.6
NA
NA
NA
NA
Beta cell function
HOMA-B
6/404
−10.69 (−19.10, −2.29)
87.1
NA
NA
NA
1/70
−14.80 (−24.76, −4.84)
NA
5/334
−9.88 (−19.69, −0.07)
89.5
0.87
HOMA-%B
2/139
4.87 (−44.59, 54.34)
84.4
NA
NA
NA
NA
NA
NA
2/139
4.87 (−44.59, 54.34)
84.4
NA
HOMA2-%B
5/320
1.57 (−3.98, 7.12)
0
NA
NA
NA
4/249
0.28 (−5.61, 6.16)
0
1/71
12.03 (−4.70, 28.76)
NA
0.29
Disposition index
4/287
−0.05 (−0.39, 0.29)
1.9
NA
NA
NA
4/287
−0.05 (−0.39, 0.29)
1.9
NA
NA
NA
NA
/: number of studies/number of participants; 25 (OH) D: 25-hydroxyvitamin D; HOMA-IR: homeostatic model assessment-insulin resistance; QUICKI: quantitative insulin sensitivity check index; WMD: weighted mean difference; 2 h glucose: 2-hour plasma glucose; 2 h insulin: 2-hour plasma insulin; NA: not applicable.
