Supplemental Material
Associations of cadmium, mercury and lead in kidney cortex and serum ferritin with urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in
living kidney donors
Journal: International Archives of Occupational and Environmental Health
Mohammad Bakhtiar Hossain1,2,*, Lars Barregard, Gerd Sallsten, Karin Broberg
1
Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund, SE-22185 Sweden
2
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh
*
Corresponding author: Mohammad Bakhtiar Hossain, Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund
University, SE-22185 Lund, Sweden. Telephone: +46 (0) 46 173148. Fax: +46 (0) 46 143201. E-mail: bakhtiar.hossain@med.lu.se.
Supplemental Table 1. Spearman’s rank correlations for metals in kidney, urinary 8-oxodG concentration and excretion rates, age, body weight, body mass index (BMI), smoking, and serum
ferritna
Kidney cadmium
K Hg K Pb U24 8-oxodG UON 8-oxodG
concentration concentration
U24 8-oxodG UON 8-oxodG
excretion rate excretion rate
Age
Body weight BMI
Smoking
S Ferritin
0.20* 0.11 -0.18
(109) (109) (95)
-0.14
(106)
-0.23*
(93)
-0.24*
(106)
0.29**
(109)
-0.29**
(107)
-0.20*
(107)
0.26**
(109)
-0.19
(108)
-0.069
(106)
-0.19
(93)
-0.20
(106)
-0.021
(109)
-0.11
(107)
-0.060
(107)
-0.075
(109)
-0.12
(108)
0.10
(106)
0.027
(93)
0.066
(106)
-0.057
(109)
0.038
(107)
-0.018
(107)
0.030
(109)
0.062
(108)
0.80**
(126)
0.60**
(127)
0.48**
(126)
0.15
(130)
0.24**
(128)
0.050
(128)
0.017
(129)
0.43**
(129)
0.61**
(123)
0.58**
(141)
0.11
(141)
0.13
(138)
0.014
(138)
0.075
(140)
0.37**
(140)
0.78**
(122)
0.060
(126)
0.42**
(124)
0.14
(124)
0.20*
(125)
0.55**
(125)
0.11
(141)
0.34**
(138)
0.14
(138)
0.091
(140)
0.51
(140)
-0.010
(149)
0.0076
(149)
-0.039
(151)
0.32**
(151)
0.78**
(149)
-0.043
(148)
0.41**
(148)
-0.051
(148)
0.20*
(148)
Kidney mercury
Kidney lead
U24 8-oxodG concentrationb
UON 8-oxodG concentrationb
U24 8-oxodG excretion rate
UON 8-oxodG excretion rate
Age
Body weight
Body mass index
-0.90 -0.13
(109) (95)
0.13
(95)
Smoking
a*p<0.05; **p<0.01; number of subjects in each correlation are given in brackets. Abbreviations: U24, 24 hour urine sample; UON, overnight urine sample.
b
Adjusted for specific gravity of urine (1.015 g/ml).
0.015
(150)
Supplementary Table 2: Linear regression analyses between 8-oxodG concentration (adjusted to specific gravity) and elements in kidney, iron status, and
other covariates
Predictor
Univariate analysesa
U24
UON
N
βb (95% CI)
p-value
N
Kidney Cd (µg/g)
95
-0.068 (-0.21 to 0.076)
0.35
106 -0.072 (-0.23 to 0.080)
0.35
Kidney Hg (µg/g)c
88
-0.47 (-1.74 to 0.79)
0.46
98
0.72
Kidney-Pb (µg/g)c
94
0.95 (-0.63 to 2.53)
0.24
105 0.83 (-0.78 to 2.43)
0.31
Serum ferritin (µg/L) 129 0.048 (0.032 to 0.065)
<0.0001
140 0.047 (0.026 to 0.067)
<0.0001
Age (years)
130 0.095 (-0.010 to 0.20)
0.076
141 0.082 (-0.040 to 0.20)
0.19
Gender
130 -3.34 (-5.47 to -1.21)
0.0024
141 -2.09 (-4.55 to 0.36)
0.094
Body weight (kg)
128 0.13 (0.050 to 0.22)
0.0019
138 0.067 (-0.030 to 0.16)
0.18
BMI (kg/m2)
128 0.22 (-0.15 to 0.58)
0.24
138 0.083 (-0.32 to 0.49)
0.68
Smokingd
129 0.56 (-2.00 to 3.13)
0.67
140 0.58 (-2.31 to 3.47)
0.69
a
-0.23 (-1.52 to 1.06)
p-value
Univariate analyses: 8-oxodG concentration (nmol/L)= α1 + β1 X element/covariate. U24=24h urine sample, UON=overnight urine sample
b
c
β (95% CI)
β= unstandardized regression coefficient
Natural log-transformed
d
current yes/no
Supplementary Table 3: Linear regression analyses between 8-oxodG excretion rates (nmol/hr) (natural log transformed) and elements in kidney, iron status,
and other covariates
Predictor
Univariate analysesa
U24
UON
N
βb (95% CI)
p-value
N
Kidney Cd (µg/g)
92
-0.0059 (-0.015 to 0.0036)
0.22
106 -0.0061 (-0.014 to 0.0020)
0.14
Kidney Hg (µg/g)c
85
-0.047 (-0.13 to 0.034)
0.25
98
0.077
Kidney-Pb (µg/g)c
91
0.020 (-0.088 to 0.13)
0.72
105 0.021 (-0.065 to 0.11)
0.62
Serum ferritin (µg/L) 125 0.0038 (0.0026 to 0.0050)
<0.0001
140 0.0032 (0.0020 to 0.0044)
<0.0001
Age (years)
126 0.0027 (-0.0051 to 0.011)
0.49
141 0.0053 (-0.0019 to 0.012)
0.15
Gender
126 -0.43 (-0.58 to -0.29)
<0.0001
141 -0.41 (-0.54 to -0.28)
<0.0001
Body weight (kg)
124 0.015 (0.0092 to 0.021)
<0.0001
138 0.013 (0.0077 to 0.018)
<0.0001
BMI (kg/m2)
124 0.027 (0.00040 to 0.054)
0.047
138 0.028 (0.0047 to 0.051)
0.019
Smokingd
125 0.26 (0.065 to 0.45)
0.0090
140 0.075 (-0.10 to 0.25)
0.40
a
-0.058 (-0.12 to 0.0063)
Univariate analyses: 8-oxodG excretion rate (nmol/hr) (natural log transformed) = α1 + β1 X element/covariate.
b
c
β (95% CI)
β= unstandardized regression coefficient
Natural log-transformed
d
current yes/no
p-value
Supplementary Table 4: Gender specific multivariable regression analysis of the relationship between 24 h urinary 8-oxodG excretion rate (nmol/hr) (natural
log transformed) and elements in kidney, considering body weight and serum ferritina
Male
Female
N
βb (95% CI)
p-value
N
β (95% CI)
p-value
Kidney Cd (µg/g)
41
0.0021 (-0.011 to 0.015)
0.74
49
-0.0018 (-0.013 to 0.010)
0.75
Body weight (kg)
41
0.011 (0.0025 to 0.020)
0.013
49
0.0026 (-0.011 to 0.016)
0.70
0.0012 (-0.00040 to 0.0027) 0.14
49
0.0059 (0.0028 to 0.0090)
0.00041
Model 1
Serum ferritin (µg/L) 41
Model 2
Kidney Hg (µg/g)c
39
-0.047 (-0.15 to 0.060)
0.38
44
-0.030 (-0.12 to 0.059)
0.50
Body weight (kg)
39
0.010 (0.0014 to 0.018)
0.024
44
0.0049 (-0.0085 to 0.018)
0.47
0.0013 (-0.00031 to 0.0029) 0.11
44
0.0056 (0.0026 to 0.0087)
0.00064
Serum ferritin (µg/L) 39
Model 3
Kidney Pb (µg/g)c
41
0.047 (-0.10 to 0.20)
0.53
48
0.012 (-0.11 to 0.13)
0.84
Body weight (kg)
41
0.011 (0.0026 to 0.019)
0.011
48
0.0025 (-0.011 to 0.016)
0.71
48
0.0057 (0.0027 to 0.0088)
0.00048
Serum ferritin (µg/L) 41
a
Models 1 (Cd)/2 (Hg)/3 (Pb): 8-oxodG concentration (nmol/L)= α1 + β1 X Kidney element (µg/g) + β2 X gender + β3 X body weight + β4 X serum ferritin.
b
c
0.00096 (-0.00067 to 0.0026)0.24
β= unstandardized regression coefficient
Natural log-transformed
Supplementary Fig. 1: Scatterplot of the association of 8-oxodG levels in 24-hr and overnight urine samples ( = 0.80, p = 2.84E-29). The values were
adjusted for specific gravity of urine (1.015 g/ml).