Cholecalciferol improves glycemic control in type 2 diabetic patients: a 6-month prospective interventional study

Figures & data

Table 1 Personal characteristics and baseline laboratory para meters of the study sample

Variables	Number of patients	Mean ± SD
Age, years	125	52.7±10.3
Duration of DM, years	125	7.7±6.1
BW, kg	125	84.9±14.5
Height, m	125	160.9±9.0
BMI, kg/m^2	125	33.0±6.1
SBP, mmHg	120	126.1±15.1
DBP, mmHg	120	73.9±8.7
Pulse, ppm	117	81.2±12.2
Vitamin D3, ng/mL	125	14.1±4.7
FPG, mmol/L	125	8.3±3.3
HbA1c	125	7.8±1.5
FI, uU/mL	57	11.6±6.5
c-peptide, ng/mL	52	2.8±0.8
HOMA-IR	57	4.1±3.0
PTH, pmol/L	79	5.4±2.5
Ca, mmol/L	101	2.3±0.1
P, mmol/L	94	1.2±0.2
AP, units/L	113	85.4±31.3
TC, mmol/L	125	4.2±1.0
LDL-C, mmol/L	123	1.1±0.3
HDL-C, mmol/L	123	1.1±0.3
TG, mmol/L	124	2.7±13.4
Creatinine, μmol/L	119	71.6±17.7
BUN, mmol/L	120	4.4±0.3
Na, mmol/L	118	138.5±2.9
K, mmol/L	120	4.4±0.3
Mg, mmol/L	51	0.8±0.1
GGT, units/L	78	41.3±30.8
RPP	117	10,252.2±1,985.6

Abbreviations: AP, alkaline phosphatase; BMI, body mass index; BUN, blood urea nitrogen; BW, body weight; D3, vitamin D3; DBP, diastolic blood pressure; FI, fasting insulin; FPG, fasting plasma glucose; GGT, gamma glutamate transferase; HbA1c, hemoglobin A1c; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostatic model assessment-Insulin resistance; LDL-C, low-density lipoprotein cholesterol; PTH, parathyroid hormone; RPP, rate pressure product; SBP, systolic blood pressure; TC, total cholesterol; TG, triglyceride; SD, standard deviation.

Table 2 Correlation between initial serum levels of vitamin D3 and measured laboratory variables

Laboratory variables	Number of patients	Pearson’s correlation coefficient, r	P-value
FPG, mmol/L	125	−0.04	0.64
HbA1c	125	0.03	0.739
FI, uU/mL	57	−0.09	0.519
c-peptide, ng/mL	52	−0.14	0.331
HOMA-IR	57	−0.13	0.331
PTH, pmol/L	79	0.02	0.878
Ca, mmol/L	101	0.15	0.142
P, mmol/L	94	−0.05	0.638
AP, units/L	113	−0.09	0.373
TC, mmol/L	124	−0.07	0.445
LDL-C, mmol/L	123	−0.14	0.119
HDL-C, mmol/L	122	0.03	0.714
TG, mmol/L	123	0.15	0.094
Creatinine, μmol/L	119	0.10	0.301
BUN, mmol/L	120	0.19	0.036
Na, mmol/L	118	−0.10	0.294
K, mmol/L	120	−0.01	0.909
Mg, mmol/L	51	0.16	0.250
GGT, units/L	78	0.03	0.789

Abbreviations: AP, alkaline phosphatase; BUN, blood urea nitrogen; FI, fasting insulin; FPG, fasting plasma glucose; GGT, gamma glutamate transferase; HbA1c, hemoglobin A1c; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostatic model assessment-Insulin resistance; LDL-C, low-density lipoprotein cholesterol; PTH, parathyroid hormone; TC, total cholesterol; TG, triglyceride.

Figure 1 Change in hemoglobin A1c (HbA1c) after vitamin D intake.

Table 3 Changes in different variables with vitamin D3 replacement

Variables	Number of patients	Before treatment, mean ± SD	After treatment, mean ± SD	P-value
BW, kg	41	85.1±12.4	85.1±13.3	0.944
BMI, kg/m^2	41	32.3±4.8	32.5±4.6	0.604
SBP, mmHg	41	123.0±15.5	119.6±13.9	0.081
DBP, mmHg	41	72.9±8.6	71.6±8.8	0.211
Pulse, ppm	41	81.6±11.9	77.5±12.0	0.045
Vitamin D3, ng/mL	41	14.0±4.0	31.0±7.9	<0.001
FPG, mmol/L	41	9.1±4.3	7.9±2.4	0.034
HbA1c	41	7.9±1.8	7.4±1.2	0.001
FI, uU/mL	12	12.9±7.6	8.5±4.1	0.069
c-peptide, ng/mL	12	2.7±0.8	2.6±0.5	0.376
HOMA-IR	12	4.7±3.5	2.6±1.1	0.058
PTH, pmol/L	20	4.6±2.1	3.5±1.8	0.001
Ca, mmol/L	27	2.3±0.1	2.3±0.1	0.752
P, mmol/L	24	1.1±0.2	1.2±0.2	0.022
AP, units/L	32	82.1±26.2	66.2±19.5	,0.001
TC, mmol/L	41	4.3±0.9	4.0±0.9	0.036
LDL-C, mmol/L	41	2.5±0.8	2.2±0.8	0.018
HDL-C, mmol/L	41	1.2±0.4	1.2±0.4	0.444
TG, mmol/L	41	1.5±0.7	1.4±0.9	0.874
Creatinine, μmol/L	38	74.6±15.6	70.7±14.7	0.047
BUN, mmol/L	38	5.3±1.4	5.0±1.5	0.223
Na, mmol/L	36	138.5±2.8	138.3±3.1	0.616
K, mmol/L	38	4.6±0.3	4.5±0.4	0.152

Abbreviations: AP, alkaline phosphatase; BMI, body mass index; BUN, blood urea nitrogen; BW, body weight; DBP, diastolic blood pressure; FI, fasting insulin; FPG, fasting plasma glucose; GGT, gamma glutamate transferase; HbA1c, hemoglobin A1c; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostatic model assessment-Insulin resistance; LDL-C, low-density lipoprotein cholesterol; PTH, parathyroid hormone; SBP, systolic blood pressure; TC, total cholesterol; TG, triglyceride; SD, standard deviation.

Figure 2 Change of serum creatinine after vitamin D intake.

Figure 3 Change in hemoglobin A1c (HbA1c) in relation with its initial level before treatment.

Table 4 Correlation coefficients between changes in laboratory variables with their initial levels before treatment

Laboratory variables	Pearson’s correlation coefficient, r	P-value
FPG, mmol/L	−0.83	<0.001
HbA1c	−0.77	<0.001
FI, uU/mL	−0.75	0.001
c-peptide, ng/mL	−0.09	0.747
Creatinine, μmol/L	−0.45	0.005
LDL-C, mmol/L	−0.43	0.005
TC, mmol/L	−0.42	0.007

Abbreviations: FI, fasting insulin; FPG, fasting plasma glucose; HbA1c, hemoglobin A1c; LDL-C, low-density lipoprotein cholesterol; TC, total cholesterol.

Table 5 Mean percent changes for different laboratory variables

Laboratory variables	Mean percent change for different variables ([B–A] ×100/A)
FI, uU/mL	22.21
c-peptide, ng/mL	1.83
HOMA-IR	27.58
TC, mmol/L	4.94
LDL-C, mmol/L	8.60
HDL-C, mmol/L	1.05
TG, mmol/L	1.86
Creatinine, μmol/L	3.59

Notes: B: the value of the measured variable after vitamin D replacement. A: the initial value of the measured variable before vitamin D replacement.

Abbreviations: FI, fasting insulin; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostatic model assessment–insulin resistance; LDL-C, low-density lipoprotein cholesterol; TC, total cholesterol; TG, triglyceride.

Table 6 Mean changes for different laboratory variables

Laboratory variables	Mean change = (before – after)
Vitamin D3, ng/mL	16.99
FPG, mmol/L	1.22
HbA1c	0.54
TC, mmol/L	0.26
LDL-C, mmol/L	0.27
HDL-C, mmol/L	0.02
TG, mmol/L	0.01

Abbreviations: FPG, fasting plasma glucose; HbA1c, hemoglobin A1c; LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; TC, total cholesterol; TG, triglyceride.

Table 8 The correlation coefficients between parathyroid hormone, alkaline phosphatase and phosphate levels with different laboratory variables

Laboratory variables	PTH	AP	P
FPG, mmol/L
r	−0.18	0.56	0.05
P-value	0.436	0.001	0.804
HbA1c
r	−0.04	0.45	0.27
P-value	0.885	0.011	0.211
TC, mmol/L
r	0.02	0.11	−0.31
P-value	0.938	0.534	0.138
LDL-C, mmol/L
r	0.01	0.16	−0.22
P-value	0.953	0.394	0.310
r	−0.45	−0.15	−0.07
P-value	0.049	0.414	0.759
BUN, mmol/L
r	0.43	−0.05	−0.00
P-value	0.061	0.789	0.992
FI, uU/mL
r	−0.17	−0.168	0.133
P-value	0.484	0.359	0.535
c-peptide, ng/mL
r	−0.22	−0.04	0.02
P-value	0.361	0.827	0.910

Abbreviations: PTH, parathyroid hormone; AP, alkaline phosphatase; P, phosphate; BUN, blood urea nitrogen; FI, fasting insulin; FPG, fasting plasma glucose; HbA1c, hemoglobin A1c; LDL-C, low-density lipoprotein cholesterol; PTH, parathyroid hormone; TC, total cholesterol; TG, triglyceride.

Table 7 Correlation between initial levels of vitamin D and changes in different laboratory variables

Laboratory variables	Pearson’s correlation coefficient, r	P-value
hFPG, mmol/L	0.29	0.074
HbA1c	0.07	0.661
FI, uU/mL	0.33	0.036
c-peptide, ng/mL	0.35	0.027
HOMA-IR	0.37	0.018
TC, mmol/L	−0.08	0.612
LDL-C, mmol/L	0.07	0.671
Creatinine, μmol/L	0.08	0.620

Abbreviations: FI, fasting insulin; FPG, fasting plasma glucose; HbA1c, hemoglobin A1c; HOMA-IR, homeostatic model assessment-Insulin resistance; LDL-C, low-density lipoprotein cholesterol; TC, total cholesterol.