1
eTable 1. Baseline Characteristics of Study Participants Included and Excluded in the Analysesa
Included (n = 4350)
Excluded (n = 1476)
Boys
2176 (50)
861 (59)
Maternal asthma
65 (2)
49 (4)
Paternal asthma
83 (2)
43 (3)
Fetal tobacco smoke exposureb
925 (22)
262 (22)
Environmental tobacco smoke exposurec
1377 (32)
401 (33)
Less than high school diploma
196 (5)
48 (4)
High school diploma
2348 (57)
690 (59)
More than high school diploma
1612 (39)
433 (37)
Less than high school diploma
185 (4)
58 (5)
High school diploma
1846 (44)
507 (43)
More than high school diploma
2157 (52)
625 (53)
Maternal education
Paternal education
1
Fish intake
None
75 (3)
26 (5)
Once/wk
1379 (48)
255 (46)
2–3 times/wk
1227 (43)
242 (43)
4–5 times/wk
126 (4)
23 (4)
>5 times/wk
43 (2)
11 (2)
1271 (29)
393 (27)
Pet ownership
2
Abbreviation: Hg, mercury.
3
aResults
4
and excluded groups.
5
bActive
6
cPresence
are shown as n (percentage). The outcome data represent 2 tests of the difference between the children in the included
maternal smoking or presence of a smoker at home during pregnancy.
of a smoker at home after delivery.
7
2
8
eTable 2. Distribution of Blood Hg Concentrations among the Study Participants during the Study Period
Selected percentiles
Biomarker
No.
of
GM (GSD)
10th
25th
50th
75th
90th
95th
observations
9
Blood Hg at 7–8 y (µg/L)
4350
2.02 (2.01)
0.89
1.42
2.17
3.24
4.34
5.14
Blood Hg at 9–10 y (µg/L)
3165
1.79 (1.83)
0.89
1.30
1.89
2.64
3.51
4.18
Blood Hg at 11–12 y (µg/L)
2088
1.96 (1.79)
0.98
1.40
2.03
2.81
3.94
4.95
Abbreviations: Hg, mercury; GM, geometric mean; GSD, geometric standard deviation.
10
3
11
eTable 3. Association of Hg Concentration with Asthma at 9–10 and 11–12 Years of Age, Stratified by Gendera
Asthma at 9–10 y
Asthma at 11–12 y
Incident Asthma
OR
95% CI
OR
95% CI
HR
95% CI
Boys
1.80
1.18–2.73
1.35
0.98–1.86
1.54
1.12–2.10
Girls
1.41
0.93–2.13
1.18
0.84–1.66
1.26
0.90–1.76
12
Abbreviations: CI, confidence interval; Hg, mercury; HR, hazards ratio; OR, odds ratio.
13
aModels
14
paternal and maternal education level, and pet ownership.
were adjusted for gender, paternal and maternal asthma history, fetal and environmental tobacco smoke exposure,
15
4
16
eTable 4. Association between Blood Hg Concentration and Asthma-related Outcomes at Ages Up to 11–12 Years after Inverse
17
Probability Weighting for Follow-upa
Wheezingb
Log Hg (µg/L)
Asthma medication usec
Airway hyperresponsivenessd
OR
95% CI
OR
95% CI
OR
95% CI
1.16
1.00–1.36
1.40
0.93–2.09
1.16
0.99–1.36
18
Abbreviations: CI, confidence interval; Hg, mercury; OR, odds ratio.
19
aModels
20
paternal and maternal education level, and pet ownership.
21
bPositive
response to the question “Has your child experienced wheezing in the past 12 months?”.
22
cPositive
response to the question “Did your child use asthma medication in the past 12 months?”.
23
dDefined
as a methacholine provocative concentration producing a 20% fall in forced expiratory volume in 1 second of≤8 mg/mL.
were adjusted for gender, paternal and maternal asthma history, fetal and environmental tobacco smoke exposure,
5
24
eTable 5. Association of Blood Hg Concentration with Asthma at 9–10 and 11–12 Years of Age in Children with Fish Consumption
25
Informationa
Asthma at 9–10 y of Age
Asthma at 11–12 y of Age
No.b
OR
95% CI
No.b
OR
95% CI
Hg at 7–8 y
79/2144
1.66
1.14–2.43
113/1287
1.39
1.03–1.88
Average Hg until 7–8 yc
79/2144
1.48
0.91–2.41
113/1287
1.33
0.89–1.99
NA
NA
NA
113/1287
1.36
0.83–2.24
Average Hg until 11–12 yd
26
Abbreviations: CI, confidence interval; Hg, mercury; OR, odds ratio.
27
aModels
28
paternal and maternal education level, and pet ownership.
were adjusted for gender, paternal and maternal asthma history, fetal and environmental tobacco smoke exposure,
6
29
bNumber
with outcome/total number for analysis.
30
cAverage
blood Hg concentration at 7–8 and 9–10 years of age.
31
dAverage
blood Hg concentration at 7–8, 9–10, and 11–12 years of age.
32
7
33
eTable 6. Association of Hg Concentration at 7–8 Years of Age with Immune System Blood Profile at Ages Up to 11–12 Years,
34
Stratified by Occurrence of Current Asthma in Children With Fish Consumption Informationa
Total (n = 2850)
WBC count
Children With
Children Without
Asthma (n = 113)
Asthma (n = 2737)
β
95% CI
β
95% CI
β (SE)
95% CI
-0.02
-0.03 to -0.01
0.01
-0.05 to 0.07
-0.02
-0.03 to 0.003
Segment neutrophil %
0.05
-0.34 to 0.45
1.72
-0.06 to 3.49
-0.01
-0.57 to 0.54
Lymphocyte %
0.003
-0.39 to 0.39
-1.68
-3.55 to 0.19
0.08
-0.48 to 0.63
Monocyte %
-0.0004
-0.01 to 0.01
0.004
-0.05 to 0.06
0.001
-0.01 to 0.02
Basophil %
0.007
-0.01 to 0.03
0.07
-0.04 to 0.17
0.01
-0.01 to 0.04
hs-CRP
0.08
0.02 to 0.14
0.40
0.12 to 0.68
0.06
-0.03 to 0.15
Total IgE
-0.06
-0.13 to 0.02
0.04
-0.38 to 0.45
-0.05
-0.16 to 0.06
35
Abbreviations: CI, confidence interval; Hg, mercury; hs-CRP, high-sensitivity C-reactive protein; OR, odds ratio; SE, standard error;
36
WBC. white blood cell.
37
aModels
were adjusted for gender, paternal and maternal asthma history, fetal and environmental tobacco smoke exposure,
8
38
paternal and maternal education level, fish intake, and pet ownership. The association of Hg with hs-CRP and total IgE in the total
39
population and the association of Hg with total IgE in children without current asthma were also adjusted for these covariates
40
except for paternal education because of a convergence problem. WBC count, monocyte percentage, basophil percentage, hs-
41
CRP, and total IgE were log-transformed for normal approximation.
42
9
43
eTABLE 7. Association between Blood Hg Concentration and Asthma at 9–10 and 11–12 Years of Age, Adjusted for Citya
Asthma at 9–10 y of Age
Asthma at 11–12 y of Age
No.b
OR
95% CI
No.b
OR
95% CI
Hg at 7–8 y
129/3197
1.46
1.07–2.00
191/2179
1.33
1.04–1.71
Average Hg until 7–8 yc
129/3197
1.62
1.10–2.37
191/2179
1.23
0.91–1.67
NA
NA
NA
191/2179
1.23
0.85–1.78
Average Hg until 11–12 yd
44
Abbreviations: CI, confidence interval; Hg, mercury; OR, odds ratio.
45
aModels
46
paternal and maternal education level, pet ownership, and city from which the study participants were recruited.
47
bNumber
were adjusted for gender, paternal and maternal asthma history, fetal and environmental tobacco smoke exposure,
with outcome/total number for analysis.
10
48
cAverage
blood Hg concentration at 7–8 and 9–10 years of age.
49
dAverage
blood Hg concentration at 7–8, 9–10, and 11–12 years of age.
50
11
51
eTable 8. Association between Blood Hg Concentration and Asthma-related Outcomes at Ages Up To 11–12 Years, Adjusted for
52
Citya
Wheezingb
Log Hg (µg/L)
Asthma medication usec
Airway hyperresponsivenessd
OR
95% CI
OR
95% CI
OR
95% CI
1.21
1.06–1.38
1.45
0.99–2.12
1.12
0.98–1.29
53
Abbreviations: CI, confidence interval; Hg, mercury; OR, odds ratio.
54
aModels
55
paternal and maternal education level, pet ownership, and city from which the study participants were recruited.
56
bPositive
response to the question “Has your child experienced wheezing in the past 12 months?”.
57
cPositive
response to the question “Did your child use asthma medication in the past 12 months?”.
58
dDefined
as a methacholine provocative concentration producing a 20% fall in forced expiratory volume in 1 second of≤8 mg/mL.
were adjusted for gender, paternal and maternal asthma history, fetal and environmental tobacco smoke exposure,
12