Environmental Lead Exposure Accelerates Progressive Diabetic Nephropathy in Type II Diabetic Patients
Table 1
Baseline characteristics of patients with high-normal and low-normal body lead burden at the beginning of the observation period*.
Variable
Low-normal BLB group
High-normal BLB group
value
()
()
()
()
Age (yr)
Mean ± SD
60.7 ± 8.3
59.8 ± 10.1
0.698
Range
46–79
33–83
Sex (no. of patients)
Men/women
17/10
41/21
0.812†
Education yrs >9 yrs (no. of patients)
13 (39.4)
30 (40.5)
0.911†
Body-mass index (kg/m2)
Mean ± SD
24.5 ± 3.0
25.1 ± 3.7
0.459
Range
17.6–32.3
14.9–33.4
Hyperlipidemia (no. of patients) (%)∧
16 (60.6)
46 (68.9)
0.210†
Use of statin drugs (no. of patients) (%)
15 (57.6)
41 (60.8)
0.352†
Hypertension (no. of patients) (%)∥
26 (97.0)
58 (94.6)
0.999†
Use of angiotensin-converting-enzyme inhibitors or angiotensin-receptor antagonists (no. of patients) (%)
27 (100.0)
60 (98.6)
0.999†
Use of nondihydropyridine calcium channel blockers (no. of patients) (%)
10 (48.5)
22 (33.8)
0.999†
Use of dihydropyridine calcium channel blockers (no. of patients) (%)
9 (27.3)
24 (40.5)
0.812†
Smoking (no. of patients) (%)
5 (15.2)
9 (24.3)
0.753†
History of cardiovascular disease (no. of patients) (%)
8 (36.4)
21 (29.7)
0.808†
Use of insulin at entry (no. of patients) (%)
6 (18.2)
16 (24.3)
0.795†
HbA1c (%)
Mean ± SD
8.2 ± 2.1
8.6 ± 1.8
0.367
Range
5.8–14.0
5.7–14.7
Mean arterial pressure (mmHg)
Mean ± SD
96.6 ± 12.0
98.6 ± 11.9
0.477
Range
68.7–120
75–126
Cholesterol (mg/dL)
Mean ± SD
211.0 ± 38.2
217.2 ± 54.5
0.596
Range
124–278
105–414
Triglycerides (mg/dL)
Mean ± SD
211.3 ± 107.2
206.2 ± 187.6
0.697
Range
91–635
56–1185
Serum creatinine (mg/dL)‡
Mean ± SD
1.79 ± 0.21
1.88 ± 0.30
0.170
Range
1.5–3.7
1.5–3.8
Creatinine clearance rate (mL/min/1.73 m2)
Mean ± SD
44.9 ± 10.8
41.1 ± 12.0
0.123
Range
29.2–61.4
24.6–70.9
Glomerular filtration rate⊙ (mL/min/1.73 m2)
Mean ± SD
42.4 ± 6.2
40.8 ± 7.1
0.380
Range
31.9–58.3
30.3–59.9
Blood lead (μg/dL)#
Mean ± SD
3.8 ± 3.0
4.6 ± 3.1
0.278
Range
1.6–10.4
0.8–10.3
Body lead burden (μg)#
Mean ± SD
58.1 ± 16.7
132.4 ± 46.1
0.001
Range
14.4–79.8
82.8–316.8
Daily protein excretion (g)
Mean ± SD
2.8 ± 2.5
3.2 ± 2.4
0.364
Range
0.5–10.5
0.5–12.2
Daily protein intake (g/kg)
Mean ± SD
0.99 ± 0.16
0.96 ± 0.18
0.569
Range
0.60–1.55
0.53–1.68
*A high-normal body lead burden was defined as a lead value of at least 80 g (0.39 μmol) but less than 600 μg (2.9 μmol) and a low-normal body lead burden as a lead value less than 80 μg (0.39 μmol). † values were calculated by Fisher’s Chi-square test, except in the comparisons of age, body-mass index, serum creatinine, creatinine clearance, glomerular filtration rate, blood lead level, and body lead burden, which were calculated by Student’s -test. ‡To convert values for serum creatinine to micromoles per liter, multiply by 88.4. ⊙Modified equation for glomerular filtration rate of Chinese diabetic patients.
#To convert values for lead to micromoles per liter, multiply by 0.04286. ∧Hyperlipidemia was defined as a serum cholesterol level above 240 mg per deciliter (6.2 mmol per liter) after diet control. ∥Hypertension was defined by the presence of at least two blood-pressure measurements above 140/90 mmHg in patients. Cardiovascular diseases included ischemic heart disease, congestive heart failure, stroke, and diabetic foot.
