Clinical characteristics of the participants in this study
The clinical data and biochemical test items of the participants were shown in Table 1. The LEAD group, including 704 T2DM patients with LEAD, the age quartile was 56 (49–63) years and 71.2% was male. For the control group, 348 T2DM patients without LEAD were included, the age quartile was 52 (42–62) years and 67.8% was male. Compared with the control group, the LEAD group patients had lower levels of biochemical indicators TP, ALB, ALT, AST, LDH, α-HBDH, SOD, AG, Ca, K, P, Mg, RBP, and Apo E. In terms of thyroid hormones, FT4 levels were significantly lower in the LEAD patients than in the without LEAD patients. However, there were no significant differences in FT3, T3, and T4 levels between the two groups.
Table 1
Clinical characteristics of T2DM patients with or without LEAD.
Characteristics | Total(1052) | Without-LEAD(348) | LEAD(704) | P |
Gender(male) | 737(70.1%) | 236(67.8%) | 501(71.2%) | 0.265 |
Age | 55(47–63) | 52(42–62) | 56(49–63) | < 0.001*** |
FT3 (pmol/L) | 4.83(4.23–5.46) | 4.91(4.25–5.52) | 4.8(4.22–5.43) | 0.068 |
FT4 (pmol/L) | 16.2(14.1–18.3) | 16.5(14.3–18.8) | 16.1(14–18) | 0.005** |
T3(ng/mL) | 1.19(1.02–1.37) | 1.18(1.02–1.37) | 1.20(1.02–1.37) | 0.832 |
T4 (µg/dL) | 7.37(6.25–8.73) | 7.50(6.41–8.80) | 7.34(6.21–8.73) | 0.331 |
TSH (ulU/mL) | 1.75(1.1–2.54) | 1.65(1.06–2.47) | 1.80(1.11–2.56) | 0.218 |
TPOAb (U/mL) | 140(13.3%) | 53(15.2%) | 87(12.4%) | 0.197 |
TP (g/L) | 66.6(63.2-70.68) | 67.2(63.43–71.68) | 66.5(63-70.2) | 0.012* |
ALB (g/L) | 41.2(38.8–43.9) | 42.05(39-44.7) | 40.9(38.7–43.7) | 0.001** |
PA (mg/L) | 255.9(219.2-292.1) | 257.3(220.9-294.9) | 254.85(218.5-291.68) | 0.787 |
GLB | 25.3(23.13–27.68) | 25.25(23.23-28) | 25.3(23.1–27.6) | 0.382 |
ALT (U/L) | 20(14–31) | 22(15.25-37) | 20(14-29.75) | 0.023* |
AST (U/L) | 19(16–24) | 19.5(16–26) | 18(15–23) | 0.006** |
I-BIL (µmol/L) | 8.1(6.4–10.7) | 8.2(6.6-10.68) | 8(6.3–10.7) | 0.415 |
DBIL (µmol/L) | 3.5(2.6–4.6) | 3.6(2.7–4.7) | 3.4(2.6–4.6) | 0.178 |
TBIL (µmol/L) | 11.5(9.1–15.3) | 11.6(9.23–15.2) | 11.5(8.9-15.38) | 0.375 |
TBA (µmol/L) | 3.7(2.5–5.8) | 3.7(2.5–5.6) | 3.75(2.5–5.98) | 0.333 |
ALP (U/L) | 67.5(55–83) | 69(55–86) | 67(55.25-82) | 0.235 |
LDH (U/L) | 179(159–201) | 184(162–206) | 177(158–197) | 0.006** |
CK (U/L) | 74(56–105) | 74(55-106.75) | 74.5(56-103.75) | 0.939 |
CK-MB (U/L) | 13(11–16) | 12(10–16) | 13(11–16) | 0.036* |
α-HBDH (U/L) | 144(127–162) | 148(132–168) | 142(126–159) | < 0.001*** |
SOD (U/mL) | 173.05(158.3-189.55) | 176.95(160.5-194.6) | 171.5(156.93-186.98) | 0.003** |
LDL (mmol/L) | 2.44(1.92–3.01) | 2.42(1.87–3.06) | 2.46(1.95-3.0) | 0.649 |
CO2CP (mmol/L) | 22.2(20-24.6) | 22(19.83–24.08) | 22.4(20.1–24.9) | 0.067 |
TG (mmol/L) | 1.44(0.99–2.2) | 1.49(1.0-2.29) | 1.42(0.98–2.16) | 0.356 |
HDL (mmol/L) | 0.98(0.85–1.15) | 0.98(0.84–1.19) | 0.97(0.85–1.14) | 0.476 |
Cr (µmol/L) | 59(50-67.75) | 59(50–68) | 58(50–67) | 0.487 |
AG (mmol/L) | 23.5(20.7–26.5) | 23.85(21.5–26.6) | 23.2(20.33–26.5) | 0.006** |
Ca (mmol/L) | 2.21(2.14–2.29) | 2.24(2.16–2.31) | 2.2(2.13–2.28) | < 0.001*** |
K (mmol/L) | 3.89(3.66–4.15) | 3.95(3.73–4.19) | 3.85(3.62–4.13) | < 0.001*** |
P (mmol/L) | 1.13(1.02–1.25) | 1.15(1.02–1.28) | 1.12(1.02–1.23) | 0.013* |
CL (mmol/L) | 103.5(101.3-105.78) | 103.4(101.13–105.7) | 103.6(101.3-105.8) | 0.393 |
Mg (mmol/L) | 0.89(0.85–0.95) | 0.9(0.85–0.96) | 0.89(0.84–0.94) | 0.012* |
Na (mmol/L) | 142(141–144) | 142(141–144) | 142(141–144) | 0.516 |
BUN (mmol/L) | 5.37(4.52–6.35) | 5.25(4.46–6.24) | 5.43(4.59–6.43) | 0.218 |
UA (µmol/L) | 316(266.25-377.75) | 327.5(267-382.5) | 312.5(266–372) | 0.232 |
GLU (mmol/L) | 6.8(5.56–8.73) | 6.69(5.56–8.67) | 6.84(5.56–8.83) | 0.724 |
RBP (mg/L) | 51.1(38.33–64.6) | 55.5(40.63–67.58) | 49.25(37.33–61.88) | < 0.001*** |
GA | 18.8(15.6-23.48) | 18.8(15.63–22.8) | 18.8(15.6–24) | 0.516 |
Apo A (g/L) | 1.18(1.05–1.30) | 1.19(1.06–1.33) | 1.17(1.05–1.29) | 0.057 |
Apo B (g/L) | 0.82(.067-0.97) | 0.8(0.65–0.98) | 0.82(0.68–0.96) | 0.753 |
Apo E (mg/L) | 34.8(27.5–45.1) | 36.8(29.23–48.78) | 34.1(27.13–43.2) | 0.001** |
Lp(A) (mg/L) | 117(59–227) | 129(61.25–229) | 114.5(57.25–225) | 0.197 |
TC (mmol/L) | 4.12(3.47–4.76) | 4.14(3.44–4.86) | 4.11(3.47–4.70) | 0.525 |
CysC (mg/L) | 0.82(0.73–0.95) | 0.82(0.72–0.94) | 0.82(0.73–0.95) | 0.850 |
Normal reference range: TSH 0.25-5.0 µIU/mL, FT4 9.05–25.5 pmol/L, FT3 2.91–9.08 pmol/L, T4 4.2–13.5 µg/dL, T3 0.78–2.2 ng/mL. *P < 0.05; **P < 0.01; ***P < 0.001. The differences between the two groups of gender were tested by Chi-square test, and others were tested by Mann-Whitney U test. |
FT3: triiodothyronine; FT4: free thyroxine; T3: triiodothyronine; T4: four iodothyronine; TSH: Thyroid Stimulating Hormone; TPOAb: thyroid peroxidase antibody; TP: total protein; ALB: albumin; PA: prealbumin; GLB: globulin; ALT: aminotransferase; AST: aminotransferase; I-BIL: indirect bilirubin; DBIL: direct bilirubin; TBIL: total bilirubin; TBA: total bile acid; ALP: alkaline phosphatase; LDH: lactate dehydrogenase; CK: creatine kinase; CK-MB: creatine phosphokinase-MB; α-HBDH: α-hydroxybutyrate dehydrogenase; SOD: Superoxide dismutase Carbon dioxide; LDL: low-density lipoprotein; CO2CP: Carbon dioxide combining power; |
TG: triglycerides; HDL: high-density lipoprotein; Cr: creatinine; AG: anion gap; |
Ca: calcium; K: potassium; P: phosphorus; CL: chlorine; Mg: magnesium; Na: sodium; BUN: Blood Urea Nitrogen; UA: Uric Acid; GLU: glucose; RBP: Retinol Binding Protein; GA: Glycated Albumin; Apo A: apolipoprotein A; Apo B: apoprotein B; Apo E: apoprotein E; Lp(A): lipoprotein a; TC: total cholesterol; CysC: Cystatin C. |
Relationship Of Ft4 And Clinical Characteristics In Lead Group
As shown in Table 2, spearman correlation analysis was used to analyze the correlation between clinical indicators and FT4 in the T2DM patients with LEAD. The results showed that FT4 level was significantly positively correlated with TP, ALB, PA, I-BIL, TBIL, α-HBDH, SOD, HDL, AG, Ca, RBP, and Apo A. At the same time, FT4 level was significantly negatively correlated with age, TBA, ALP, CO2CP, GA.
Table 2
Correlations between FT4 and clinical characteristics among T2DM patients with LEAD.
clinical characteristics | r value | P | clinical characteristics | r value | P |
Gender | 0.03 | 0.423 | HDL(mmol/L) | 0.124 | 0.001** |
Age | -0.078 | 0.039* | Cr (µmol/L) | -0.03 | 0.43 |
TP (g/L) | 0.163 | < 0.001*** | AG (mmol/L) | 0.102 | 0.007** |
ALB (g/L) | 0.243 | < 0.001*** | Ca (mmol/L) | 0.15 | < 0.001*** |
PA (mg/L) | 0.125 | 0.001** | K (mmol/L) | -0.001 | 0.976 |
GLB | 0.002 | 0.958 | P (mmol/L) | -0.006 | 0.871 |
ALT (U/L) | -0.051 | 0.173 | Cl (mmol/L) | -0.063 | 0.095 |
AST (U/L) | -0.017 | 0.66 | Mg (mmol/L) | 0.014 | 0.718 |
I-BIL (µmol/L) | 0.077 | 0.042* | Na (mmol/L) | 0.009 | 0.816 |
DBIL (µmol/L) | 0.068 | 0.072 | BUN (mmol/L) | 0.009 | 0.818 |
TBIL (µmol/L) | 0.08 | 0.033* | UA (µmol/L) | 0.046 | 0.218 |
TBA (µmol/L) | -0.082 | 0.029* | GLU (mmol/L) | -0.011 | 0.772 |
ALP (U/L) | -0.094 | 0.013* | RBP(mg/L) | 0.221 | < 0.001*** |
LDH (U/L) | 0.017 | 0.657 | GA | -0.074 | 0.048* |
CK (U/L) | -0.018 | 0.636 | Apo A (g/L) | 0.16 | < 0.001*** |
CK-MB (U/L) | -0.031 | 0.418 | Apo B (g/L) | 0.039 | 0.301 |
α-HBDH (U/L) | 0.105 | 0.006** | Apo E (mg/L) | 0.026 | 0.499 |
SOD (U/mL) | 0.23 | < 0.001*** | Lp(A) (mg/L) | 0.01 | 0.794 |
LDL (mmol/L) | 0.035 | 0.355 | TC (mmol/L) | 0.028 | 0.456 |
CO2CP mmol/L) | -0.079 | 0.036* | Cys C (mg/L) | -0.069 | 0.067 |
TG(mmol/L) | -0.01 | 0.786 | | | |
Correlations between FT4 and clinical characteristics were tested by Spearman correlation analysis. *P value < 0.05; **P < 0.01; ***P < 0.001. FT3: triiodothyronine; FT4: free thyroxine; T3: triiodothyronine; T4: four iodothyronine; TSH: Thyroid Stimulating Hormone; TPOAb: thyroid peroxidase antibody; TP: total protein; ALB: albumin; PA: prealbumin; GLB: globulin; ALT: aminotransferase; AST: aminotransferase; I-BIL: indirect bilirubin; DBIL: direct bilirubin; TBIL: total bilirubin; TBA: total bile acid; ALP: alkaline phosphatase; LDH: lactate dehydrogenase; CK: creatine kinase; CK-MB: creatine phosphokinase-MB; α-HBDH: α-hydroxybutyrate dehydrogenase; SOD: Superoxide dismutase Carbon dioxide; LDL: low-density lipoprotein; CO2CP: Carbon dioxide combining power; |
TG: triglycerides; HDL: high-density lipoprotein; Cr: creatinine; AG: anion gap; |
Ca: calcium; K: potassium; P: phosphorus; CL: chlorine; Mg: magnesium; Na: sodium; BUN: Blood Urea Nitrogen; UA: Uric Acid; GLU: glucose; RBP: Retinol Binding Protein; GA: Glycated Albumin; Apo A: apolipoprotein A; Apo B: apoprotein B; Apo E: apoprotein E; Lp(A): lipoprotein a; TC: total cholesterol; CysC: Cystatin C. |
The Prevalence Of Lead Among Ft4, T4, Ft3, T3, And Tsh Groups
As show in Table 3, the prevalence of LEAD in FT4 quartiles was 70.88% (< 14.1 pmol/L), 68.65% (14.1–16.2 pmol/L), 69.09% (16.2–18.3 pmol/L), and 59.09% (≥ 18.3 pmol/L), respectively. Compared with the last quartile group, we found that when the level of FT4 was lower than 18.3 pmol/L, the prevalence of LEAD remarkably increased (P < 0.05). There were no significant differences among T4 groups, FT3 groups, T4 groups, and THS groups in the prevalence of LEAD.
Table 3
The prevalence of LEAD among FT4, T4, FT3, T3, and TSH groups.
Group | Total Number | LEAD | X2 | P |
Number | Prevalence (%) |
TSH (ulU/mL) <2.5 | 776 | 514 | 66.24 | 0.623 | 0.430 |
≥ 2.5 | 276 | 190 | 68.84 | | |
FT4 (pmol/L) < 14.1 | 261 | 185 | 70.88 | 10.086 | 0.018* |
14.1–16.2 | 252 | 173 | 68.65 | | |
16.2–18.3 | 275 | 190 | 69.09 | | |
≥ 18.3 | 264 | 156 | 59.09 | | |
FT3 (pmol/L) < 4.23 | 259 | 176 | 67.95 | 5.173 | 0.160 |
4.23–4.83 | 263 | 189 | 71.86 | | |
4.83–5.46 | 267 | 172 | 64.42 | | |
≥ 5.56 | 263 | 167 | 63.50 | | |
T4 (µg/dL) <6.25 | 262 | 188 | 71.76 | 4.089 | 0.252 |
6.25–7.37 | 263 | 168 | 63.88 | | |
7.37–8.73 | 262 | 172 | 65.65 | | |
≥ 8.73 | 265 | 176 | 66.42 | | |
T3 (ng/mL) <1.02 | 253 | 169 | 66.80 | 41.278 | 0.734 |
1.02–1.19 | 268 | 174 | 64.93 | | |
1.19–1.37 | 259 | 180 | 69.50 | | |
≥ 1.37 | 272 | 181 | 66.54 | | |
The prevalence of LEAD among FT4, T4, FT3, T3, and TSH groups were tested by Chi-square test. *P value < 0.05. TSH: Thyroid Stimulating Hormone; FT4: free thyroxine; FT3: triiodothyronine; four iodothyronine; T3: triiodothyronine. |
Correlations Between Thyroid Hormone Levels And The Prevalence Of Lead
Logistic regression analysis was used to analyze the correlation between FT4, T4, FT3, T3 and TSH and the prevalence of LEAD, and the results were shown in Table 4. The last group FT4 Q4 (≥ 18.3 pmol/L) was used as a reference for comparison, the crude ORs ((95% CI) for LEAD in FT4 Q1 (< 14.1 pmol/L), FT4 Q2 (14.1–16.2 pmol/L), and FT4 Q3 (16.2–18.3 pmol/L) were 1.685 (1.173–2.422), 1.516 (1.056–2.177), and 0.548 (1.086–2.206) (P = 0.005, P = 0.024, P = 0.016)(Model 1), respectively. After adjusting for age, gender, TP, ALB, ALT, AST, LDH, CK-MB, α-HBDH, SOD, AG, Ca, K, P, Mg, RBP and Apo E, the ORs (95% CI) for LEAD in FT4 Q1 (< 14.1 pmol/L), FT4 Q2 (14.1–16.2 pmol/L), and FT4 Q3 (16.2–18.3 pmol/L) were 1.415 (0.940–2.132), 1.393 (0.942–2.059), and 1.569 (1.071–2.297) (P = 0.097, P = 0.097, P = 0.021) (Model 2), respectively. TSH, FT3, T4 and T3 groups had no significant correlation with LEAD.
Table 4
Logistic regression analysis of thyroid hormone levels with LEAD.
Characteristics | Groups | Number | Model 1 OR (95% CI) | P | Model 2 OR (95% CI) | P |
TSH | < 2.5 ≥ 2.5 | 776 276 | 0.888(0.661–1.193) Reference | 0.430 | 0.943(0.685–1.299) Reference | 0.721 |
FT4 | < 14.1 14.1–16.2 16.2–18.3 ≥ 18.3 | 261 252 275 264 | 1.685(1.173–2.422) 1.516(1.056–2.177) 1.548(1.086–2.206) Reference | 0.005** 0.024* 0.016* | 1.415(0.940–2.132) 1.393(0.942–2.059) 1.569(1.071–2.297) Reference | 0.097 0.097 0.021* |
FT3 | < 4.23 4.23–4.83 4.83–5.46 ≥ 5.56 | 259 263 267 263 | 1.219(0.849–1.751) 1.468(1.016–2.121) 1.041(0.730–1.484) Reference | 0.284 0.041* 0.825 | 0.854(0.558–1.308) 1.194(0.797–1.789) 0.945(0.646–1.382) Reference | 0.469 0.390 0.772 |
T4 | < 6.25 6.25–7.37 7.37–8.73 ≥ 8.73 | 262 263 262 265 | 1.285(0.887–1.861) 0.894(0.625–1.279) 0.966(0.674–1.3866) Reference | 0.185 0.541 0.853 | 1.175(0.783–1.764) 0.757(0.513–1.118) 0.932(0.634–1.369) Reference | 0.436 0.162 0.718 |
T3 | < 1.02 1.02–1.19 1.19–1.37 ≥ 1.37 | 253 268 259 272 | 1.012(0.703–1.454) 0.931(0.652–1.328) 1.146(0.795–1.651) Reference | 0.925 0.692 0.466 | 0.751(0.493–1.142) 0.722(0.488–1.069) 1.157(0.783–1.709) Reference | 0.181 0.104 0.464 |
Model 1: crude model. Model 2: adjusted for age, gender, TP, ALB, ALT, AST, LDH, CK-MB, α-HBDH, SOD, AG, Ca, K, P, Mg, RBP and Apo E. The logistic regression analysis was used to analyze the correlation between thyroid hormone levels and the prevalence of LEAD. *P value < 0.05; **P < 0.01; ***P < 0.001. TSH: Thyroid Stimulating Hormone; FT4: free thyroxine; FT3: triiodothyronine; four iodothyronine; T3: triiodothyronine. |