The study population (n = 368) included males and females aged 26–86 years. There were no significant differences in age, fasting FBG, AST, Ghb, cholesterol, HDL, LDL, triglycerides, total protein, ALB, WBC, ALP and 25(OH)D (all p > 0.05). Male participants had a lower BMI (p = 0.01), higher diastolic blood pressure (p = 0.03), higher urea nitrogen (BuN) (p < 0.001), Cr (p = 0.02), uric acid (UA) (p = 0.01), ALT (p = 0.03). and GGT (p = 0.01) Baseline characteristics of participants were summarized in Table 1.
Table 1
Baseline characteristic of participants in the cross-sectional study.
Variable | All participants | Males | Female | p-value |
aAge (year) | 49.00 [12.00] | 48.00 [11.75] | 49.00 [12.00] | 0.76 |
BMI (kg/m2) | 24.61±3.16 | 24.61±3.16 | 25.27±3.38 | 0.01 |
aSBP (mmHg) | 119.0 [14.0] | 123.0 [16.0] | 118.0 [13.0] | 0.12 |
aDBP (mmHg) | 75.00 [11.00] | 79.00 [12.00] | 73.00 [10.00] | 0.03 |
aGLU (mmol/L) | 5.28 [0.84] | 5.36 [0.88] | 5.15 [0.66] | 0.59 |
aBUN (mmol/L) | 5.37 [1.75] | 5.59 [1.50] | 4.85 [1.60] | < 0.001 |
aCreatinine (umol/L) | 70.00 [21.00] | 76.00 [13.00] | 53.00 [16.00] | 0.02 |
UA (umol/L) | 332.4±86.9 | 366.5±77.8 | 265.2±61.0 | 0.01 |
aAST (U/L) | 21.00 [9.00] | 21.00 [9.00] | 19.50 [7.75] | 0.06 |
aHbA1C (%) | 5.50 [0.55] | 5.50 [0.55] | 5.50 [0.50] | 0.29 |
HDL (mmol/L) | 1.27 [0.45] | 1.21 [0.35] | 1.32 [0.52] | 0.06 |
aLDL (mmol/L) | 2.93 [1.05] | 3.09 [1.28] | 2.84 [1.06] | 0.15 |
aTriglyceride (mmol/L) | 1.38 [1.10] | 1.93 [1.36] | 1.11 [1.03] | 0.06 |
TP (g/L) | 74.70±3.80 | 74.49±3.69 | 75.12±3.99 | 0.71 |
Alb (g/L) | 47.86±2.67 | 44.52±3.94 | 49.18±2.15 | 0.55 |
aWBC (109/L) | 5.92 [1.90] | 5.99 [1.26] | 5.63 [1.47] | 0.39 |
aGGT (U/L) | 24.00 [27.75] | 25.50 [16.75] | 15.5 [12.75] | 0.01 |
aALT (U/L) | 21.00 [18.75] | 25.00 [20.75] | 15.00 [12.75] | 0.03 |
aALP (U/L) | 74.00 [25.00] | 75.00 [24.00] | 67.00 [24.00] | 0.06 |
a25(OH)D (nmol/L) | 22.85 [18.25] | 22.65 [19.35] | 23.95 [15.65] | 0.83 |
ALT: alanine aminotransferase; ALP: alkaline phosphatase; BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; GGT: γ-glutamyl transferase; HDL: high-density lipoprotein; LDL: low-density lipoprotein; 25(OH)D: 25-hydroxyvitamin D. |
a Data are presented as median [IQR] due to non-normal distribution |
The bivariate correlations of ALT, GGT and ALP was presented in Table 2.
Table 2
Correlations of 25(OH)D, anthropometric, metabolic and inflammatory markers withGGT, ALT and ALP.
| GGT r (p-value) | ALT r (p-value) | ALP r (p-value) |
25(OH)D (nmol/L) | 0.036 (0.489) | -0.038 (0.466) | 0.026 (0.623) |
Age (year) | 0.042 (0.039) | -0.156 (0.218) | 0.047 (0.122) |
BMI (kg/m2) | 0.128 (0.041) | -0.057 (0.233) | 0.031 (0.059) |
SBP (mmHg) | 0.063 (0.051) | 0.103 (0.154) | 0.164 (0.201) |
DBP (mmHg) | 0.131 (0.043) | -0.097 (0.058) | 0.212 (0.049) |
GLU (mmol/L) | 0.122 (0.031) | 0.631 (0.007) | 0.245 (0.010) |
BUN (mmol/L) | 0. 283 (0.242) | 0.156 (0.214) | 0.334 (0.257) |
Creatinine (umol/L) | 0.327 (0.839) | 0.324 (0.127) | 0.442 (0.041) |
UA (umol/L) | 0. 083 (0.443) | 0.051 (0. 147) | 0.304 (0.759) |
AST (U/L) | 0.029 (0.334) | 0.024 (0.165) | 0.543 (0.148) |
HbA1C (%) | 0. 423 (0.047) | 0.068 (0. 205) | 0.121 (0.032) |
HDL (mmol/L) | 0.214 (0.326) | 0.540 (0.005) | 0.129 (0.504) |
LDL (mmol/L) | 0.229 (0.235) | 0.115 (0.608) | -0.045 (0.123) |
Triglyceride (mmol/L) | 0. 255 (0.011) | 0.129 (0. 094) | 0.216 (0.026) |
TP (g/L) | 0.034 (0.059) | 0.128 (0.031) | 0.112 (0.066) |
Alb (g/L) | 0. 133 (0.061) | 0.072 (0. 147) | 0.056 (0.043) |
WBC (109/L) | 0.058 (0.129) | 0.320 (0.071) | 0.132 (0.095) |
GGT (U/L) | | 0.322 (< 0.001) | 0.320 (< 0.001) |
ALT (U/L) | 0.322 (< 0.001) | | 0.166 (0.001) |
ALP (U/L) | 0.320 (< 0.001) | 0.166 (0.001) | |
ALT: alanine aminotransferase; ALP: alkaline phosphatase; BMI: body mass index; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; GGT: γ-glutamyl transferase; HDL: high-density lipoprotein; LDL: low-density lipoprotein; 25(OH)D: 25-hydroxyvitamin D. |
No significant correlation between 25(OH)D and any liver enzyme levels were observed (all p > 0.05). GGT was positively related to age and BMI (p = 0.039 and 0.041, respectively).
ALP was positively correlated with diastolic blood pressure (p < 0.05) and GGT was also positively related to diastolic blood pressure (p = 0.045).The three liver enzymes were positively related to each other and to FBG (all p < 0.05). However, there were no correlations between any liver enzyme levels and BuN, the same with UA (all p > 0.05). There was no relationship between the three enzymes and the lipid profile (all p > 0.05).
Lipid profile and AST were not associated with any liver enzymes (all p > 0.05). GGT and ALP were positively related to Ghb (p = 0.047 and 0.032 respectively).There was a positive relationship between ALT and HDL(p = 0.047). GGT and ALP were positively associated with triglycerides (p < 0.05). However, three liver enzymes had no correlations with the levels of ALB and WBC (all p > 0.05).
There were no significant associations of GGT, ALT, ALP levels to 25(OH)D concentration after adjustments for covariates including age, BMI, sex, BuN, Cr, UA,AST, Ghb, cholesterol, HDL, LDL, and total protein, ALB and WBC in multiple linear regression analysis (Table 3a–3c) (all p > 0.1).In these models, GGT was associated with sex (p < 0.01) (Table 3a). ALT was related to sex and BuN (all p < 0.05) (Table 3b). ALP was associated with AST and triglycerides (all p < 0.05).
Table 3a.
Multiple linear regression analyses for GGT.
Dependent variable | Independent variable | Model 1 | Model 2 |
β | p-value | β | p-value |
GGT | 25(OH)D | 0.23 | 0.12 | 0.07 | 0.45 |
| Age | -0.02 | 0.57 | 0.31 | 0.15 |
| BMI | 0.03 | 0.45 | 0.18 | 0.06 |
| Sex | 0.39 | < 0.01 | 0.27 | 0.44 |
| SBP | | | | |
| DBP | | | | |
| GLU | | | 0.07 | 0.06 |
| BUN | 0.16 | 0.25 | 0.29 | 0.37 |
| Creatinine | -0.07 | 0.44 | 0.31 | 0.45 |
| UA | 0.31 | 0.15 | 0.18 | 0.19 |
| AST | 0.19 | 0.07 | 0.27 | 0.56 |
| HbA1C | 0.04 | 0.05 | 0.25 | 0.20 |
| HDL | 0.28 | 0.27 | 0.13 | 0.55 |
| LDL | 0.37 | 0.42 | 0.24 | 0.05 |
| Triglyceride | 0.15 | 0.29 | | |
| TP | 0.07 | 0.53 | 0.22 | 0.38 |
| Alb | 0.24 | 0.10 | 0.21 | 0.41 |
| WBC | 0.11 | 0.61 | 0.39 | 0.57 |
| R2 (p-value) | 0.46 | < 0.01 | 0.45 | < 0.01 |
Model 1: adjusted for age, sex, BMI, SBP, DBP, BUN, Creatinine, UA, AST, HbA1C, HDL, LDL, Triglyceride, TP, Alb, WBC. |
Model 2 adjusted for age, sex, BMI, SBP, DBP, GLU, BUN, Creatinine, UA, AST, HbA1C, HDL, LDL, TP, Alb, WBC. |
Table 3b.
Multiple linear regression analyses for ALT.
Dependent variable | Independent variable | Model 1 | Model 2 |
β | p-value | β | p-value |
ALT | 25(OH)D | 0.14 | 0.26 | 0.08 | 0.34 |
| Age | 0.05 | 0.39 | 0.22 | 0.17 |
| BMI | 0.16 | 0.41 | 0.35 | 0.19 |
| Sex | 0.34 | 0.02 | -0.07 | 0.31 |
| SBP | 0.07 | 0.23 | 0.14 | 0.07 |
| DBP | -0.14 | 0.12 | -0.12 | 0.26 |
| GLU | | | 0.18 | 0.05 |
| BUN | 0.17 | 0.02 | 0.13 | 0.30 |
| Creatinine | 0.29 | 0.38 | 0.26 | 0.14 |
| UA | 0.28 | 0.43 | -0.02 | 0.29 |
| AST | 0.17 | 0.06 | 0.03 | 0.57 |
| HbA1C | 0.09 | 0.45 | 0.38 | 0.11 |
| HDL | 0.31 | 0.15 | | |
| LDL | 0.18 | 0.06 | 0.27 | 0.18 |
| Triglyceride | 0.27 | 0.34 | 0.24 | 0.03 |
| TP | -0.02 | 0.13 | 0.39 | 0.21 |
| Alb | 0.42 | 0.15 | 0.46 | 0.35 |
| WBC | 0.33 | 0.27 | 0.48 | 0.23 |
| R2 (p-value) | 0.31 | < 0.01 | 0.16 | < 0.01 |
Model 1: adjusted for age, sex, BMI, SBP, DBP, BUN, Creatinine, UA, AST, HbA1C, HDL, LDL, Triglyceride, TP, Alb, WBC. |
Model 2 Model 1: adjusted for age, sex, BMI, SBP, DBP, GLU, BUN, Creatinine, UA, AST, HbA1C, LDL, Triglyceride, TP, Alb, WBC. |
Table 3c.Multiple linear regression analyses for ALP.
Dependent variable
|
Independent variable
|
Model 1
|
Model 2
|
β
|
p-value
|
β
|
p-value
|
ALP
|
25(OH)D
|
0.31
|
0.34
|
0.21
|
0.23
|
|
Age
|
0.07
|
0.25
|
-0.09
|
0.21
|
|
BMI
|
0.35
|
0.23
|
0.16
|
0.39
|
|
Sex
|
0.12
|
0.56
|
0.17
|
0.32
|
|
SBP
|
0.21
|
0.09
|
0.22
|
0.17
|
|
DBP
|
-0.15
|
0.06
|
-0.09
|
0.28
|
|
GLU
|
|
|
0.19
|
0.31
|
|
BUN
|
0.17
|
0.12
|
0.16
|
0.28
|
|
Creatinine
|
0.24
|
0.38
|
0.29
|
0.37
|
|
UA
|
0.23
|
0.06
|
0.18
|
0.06
|
|
AST
|
0.17
|
0.03
|
0.13
|
0.34
|
|
HbA1C
|
-0.09
|
0.47
|
0.26
|
0.17
|
|
HDL
|
0.21
|
0.39
|
|
|
|
LDL
|
0.15
|
0.08
|
0.55
|
0.19
|
|
Triglyceride
|
0.36
|
0.32
|
0.24
|
0.03
|
|
TP
|
-0.02
|
0.16
|
-0.04
|
0.23
|
|
Alb
|
0.42
|
0.15
|
0.46
|
0.56
|
|
WBC
|
0.33
|
0.27
|
0.42
|
0.22
|
|
R2 (p-value)
|
0.24
|
<0.01
|
0.19
|
<0.01
|
Model 1: adjusted for age, sex, BMI, SBP, DBP, BUN, Creatinine, UA, AST, HbA1C, HDL, LDL, Triglyceride, TP, Alb, WBC.
Model 2: adjusted for age, sex, BMI, SBP, DBP, GLU, BUN, Creatinine, UA, AST, HbA1C, HDL, LDL, TP, Alb, WBC.
When classified by 25 (OH) D concentration, the 25 (OH) D of 6 participants was > 50 nmol/L, the 25 (OH) D of 159 participants was 25–50 nmol/L, and the 25 (OH) D of 203 participants was less than 25 nmol/L.No significant differences were observed in GGT, ALT and ALP according to the categories of vitamin D concentration (Kruskal-Wallis test, all p > 0.05).