J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website http://www.jocmr.org

Original Article

Volume 9, Number 12, December 2017, pages 1013-1018

Association of Glycosylated Hemoglobin Levels With Vitamin D Status

**Table 1.** Baseline Characteristics of the Study Participants
Baseline characteristics
HbA1c: glycated hemoglobin; TSH: thyroid-stimulating hormone; FT4: free thyroxine; C.Ca: corrected calcium; T1DM: type 1 diabetes mellitus; T2DM: type 2 diabetes mellitus.
Age (years) (mean ± SD)	43.124 ± 19.46
HbA1c pre-supplementation (%) (mean ± SD)	10.55 ± 2.58
Vitamin D pre-supplementation (nmol/L) (mean ± SD)	40.09 ± 23.13
HbA1c post-supplementation (%) (mean ± SD)	7.70 ± 1.61
Vitamin D post-supplementation (nmol/L) (mean ± SD)	80.5 ± 29.77
TSH (mIU/L) (mean ± SD)	2.89 ± 2.48
FT4 (pmol/L) (mean ± SD)	15.89 ± 8.08
C.Ca (mmol/L) (mean ± SD)	2.32 ± 0.13
Male, N (%)	397 (39.7%)
Female, N (%)	603 (60.3%)
T1DM, N (%)	338 (33.8%)
T2DM, N (%)	662 (66.2%)

Table 1. Baseline Characteristics of the Study Participants

Baseline characteristics

HbA1c: glycated hemoglobin; TSH: thyroid-stimulating hormone; FT4: free thyroxine; C.Ca: corrected calcium; T1DM: type 1 diabetes mellitus; T2DM: type 2 diabetes mellitus.

Age (years) (mean ± SD)

43.124 ± 19.46

HbA1c pre-supplementation (%) (mean ± SD)

10.55 ± 2.58

Vitamin D pre-supplementation (nmol/L) (mean ± SD)

40.09 ± 23.13

HbA1c post-supplementation (%) (mean ± SD)

7.70 ± 1.61

Vitamin D post-supplementation (nmol/L) (mean ± SD)

80.5 ± 29.77

TSH (mIU/L) (mean ± SD)

2.89 ± 2.48

FT4 (pmol/L) (mean ± SD)

15.89 ± 8.08

C.Ca (mmol/L) (mean ± SD)

2.32 ± 0.13

Male, N (%)

397 (39.7%)

Female, N (%)

603 (60.3%)

T1DM, N (%)

338 (33.8%)

T2DM, N (%)

662 (66.2%)

**Table 2.** Baseline Characteristics Grouped on Basis of Vitamin D Levels
Baseline characteristics	Vitamin D group	P value
HbA1c: glycated hemoglobin; TSH: thyroid-stimulating hormone; FT4: free thyroxine; C.Ca: corrected calcium; T1DM: type 1 diabetes mellitus; T2DM: type 2 diabetes mellitus.
Age (years) (mean ± SD)	38.61 ± 18.88	41.0 ± 19.33	49.96 ± 17.5	51.64 ± 55.5	0.0001
HbA1c pre-supplementation (%) (mean ± SD)	10.62 ± 2.45	10.86 ± 2.6	9.93 ± 2.56	9.81 ± 2.52	0.0001
Vitamin D pre-supplementation (nmol/L) (mean ± SD)	14.17 ± 3.88	33.58 ± 8.29	60.33 ± 7.03	91.75 ± 15.14	0.0001
HbA1c post-supplementation (%) (mean ± SD)	7.63 ± 1.61	7.89 ± 1.70	7.37 ± 1.39	7.4 ± 1.16	0.0001
Vitamin D post-supplementation (nmol/L) (mean ± SD)	68.11 ± 29.02	74.46 ± 25.82	92.27 ± 20.02	118.66 ± 31.12	0.0003
TSH (mIU/L) (mean ± SD)	3.15 ± 3.33	2.96 ± 2.42	2.6 ± 1.99	2.52 ± 1.46	0.0001
FT4 (pmol/L) (mean ± SD)	15.44 ± 2.73	16.09 ± 10.42	15.9 ± 4.67	15.69 ± 2.36	0.81
C.Ca (mmol/L) (mean ± SD)	2.3 ± 0.15	2.32 ± 0.13	2.32 ± 0.12	2.34 ± 0.10	0.043
Male, N (%)	56 (30.4%)	237 (43.3%)	67 (37.9%)	37 (40.2%)	0.019
Female, N (%)	128 (69.6%)	310 (56.7%)	110 (62.1%)	55 (59.8%)
T1DM, N (%)	71 (38.6%)	209 (38.2%)	37 (20.9%)	21 (22.8%)	0.000017
T2DM, N (%)	113 (61.4%)	338 (61.8%)	140 (79.1%)	71 (77.2%)

Table 2. Baseline Characteristics Grouped on Basis of Vitamin D Levels

Baseline characteristics

Vitamin D group

P value

< 20

≥ 20 and < 50

≥ 50 and < 75

≥ 75

HbA1c: glycated hemoglobin; TSH: thyroid-stimulating hormone; FT4: free thyroxine; C.Ca: corrected calcium; T1DM: type 1 diabetes mellitus; T2DM: type 2 diabetes mellitus.

Age (years) (mean ± SD)

38.61 ± 18.88

41.0 ± 19.33

49.96 ± 17.5

51.64 ± 55.5

0.0001

HbA1c pre-supplementation (%) (mean ± SD)

10.62 ± 2.45

10.86 ± 2.6

9.93 ± 2.56

9.81 ± 2.52

0.0001

Vitamin D pre-supplementation (nmol/L) (mean ± SD)

14.17 ± 3.88

33.58 ± 8.29

60.33 ± 7.03

91.75 ± 15.14

0.0001

HbA1c post-supplementation (%) (mean ± SD)

7.63 ± 1.61

7.89 ± 1.70

7.37 ± 1.39

7.4 ± 1.16

0.0001

Vitamin D post-supplementation (nmol/L) (mean ± SD)

68.11 ± 29.02

74.46 ± 25.82

92.27 ± 20.02

118.66 ± 31.12

0.0003

TSH (mIU/L) (mean ± SD)

3.15 ± 3.33

2.96 ± 2.42

2.6 ± 1.99

2.52 ± 1.46

0.0001

FT4 (pmol/L) (mean ± SD)

15.44 ± 2.73

16.09 ± 10.42

15.9 ± 4.67

15.69 ± 2.36

0.81

C.Ca (mmol/L) (mean ± SD)

2.3 ± 0.15

2.32 ± 0.13

2.32 ± 0.12

2.34 ± 0.10

0.043

Male, N (%)

56 (30.4%)

237 (43.3%)

67 (37.9%)

37 (40.2%)

0.019

Female, N (%)

128 (69.6%)

310 (56.7%)

110 (62.1%)

55 (59.8%)

T1DM, N (%)

71 (38.6%)

209 (38.2%)

37 (20.9%)

21 (22.8%)

0.000017

T2DM, N (%)

113 (61.4%)

338 (61.8%)

140 (79.1%)

71 (77.2%)

**Table 3.** Mean Change of Vitamin D Levels and HbA1c at Follow-Up
Vitamin D	n	Vitamin D baseline (mean ± SD)	HbA1c baseline (mean ± SD)	Vitamin D follow-up (mean ± SD)	HbA1c follow-up (mean ± SD)	Mean change vitamin D (P value)	Mean change HbA1c (P value
HbA1c: glycated hemoglobin.
< 20	184	14.17 ± 3.89	10.62 ± 2.45	68.11 ± 29.02	7.63 ± 1.61	+53.94 (0.0001)	-2.99 (0.0001)
≥ 20 and < 50	547	33.58 ± 8.23	10.86 ± 2.6	74.46 ± 25.84	7.89 ± 1.7	+40.88 (0.0001)	-2.97 (0.0001)
≥ 50 and < 75	177	60.33 ± 7.03	9.93 ± 2.56	92.27 ± 20.02	7.37 ± 1.39	+31.94 (0.0001)	-2.56 (0.0001)
≥ 75	92	91.75 ± 15.14	9.81 ± 2.52	118.66 ± 31.12	7.4 ± 1.16	+26.91 (0.0001)	-2.41 (0.0001)

Table 3. Mean Change of Vitamin D Levels and HbA1c at Follow-Up

Vitamin D

Vitamin D baseline (mean ± SD)

HbA1c baseline (mean ± SD)

Vitamin D follow-up (mean ± SD)

HbA1c follow-up (mean ± SD)

Mean change vitamin D (P value)

Mean change HbA1c (P value

HbA1c: glycated hemoglobin.

< 20

184

14.17 ± 3.89

10.62 ± 2.45

68.11 ± 29.02

7.63 ± 1.61

+53.94 (0.0001)

-2.99 (0.0001)

≥ 20 and < 50

547

33.58 ± 8.23

10.86 ± 2.6

74.46 ± 25.84

7.89 ± 1.7

+40.88 (0.0001)

-2.97 (0.0001)

≥ 50 and < 75

177

60.33 ± 7.03

9.93 ± 2.56

92.27 ± 20.02

7.37 ± 1.39

+31.94 (0.0001)

-2.56 (0.0001)

≥ 75

91.75 ± 15.14

9.81 ± 2.52

118.66 ± 31.12

7.4 ± 1.16

+26.91 (0.0001)

-2.41 (0.0001)

**Table 4.** Coefficient of Correlation Between Groups
Vitamin D	n	Vitamin D follow-up (mean ± SD)	HbA1c post-supplementation (mean ± SD)	Coefficient of correlation	P value
HbA1c: glycated hemoglobin.
≥ 20 and < 50	164	41.34 ± 5.35	7.95 ± 1.70	-0.02	0.79
≥ 50 and < 75	288	62.94 ± 7.33	8.03 ± 1.84	0	0.97
≥ 75	548	101.5 ± 22.83	7.46 ± 1.39	-0.1	0.02

Table 4. Coefficient of Correlation Between Groups

Vitamin D

Vitamin D follow-up (mean ± SD)

HbA1c post-supplementation (mean ± SD)

Coefficient of correlation

P value

HbA1c: glycated hemoglobin.

≥ 20 and < 50

164

41.34 ± 5.35

7.95 ± 1.70

-0.02

0.79

≥ 50 and < 75

288

62.94 ± 7.33

8.03 ± 1.84

0.97

≥ 75

548

101.5 ± 22.83

7.46 ± 1.39

-0.1

0.02