Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R study – Supplementary information

Figure S1: DAP metabolite levels for the subset of 120 pregnant women from the Generation R cohort (nmol/L)

NB. The boxplots represent the 10th, 25th, 50th, 75th and 90th percentiles (boxes) as well as the outliers (dots) of the underlying distribution

Table S1: DAP metabolite levels for the subset of 120 pregnant women from the Generation R cohort (nmol/L)

Metabolite / Period / N / #<LOQ / AM / GM / GSD / min / p5 / p25 / p50 / p75 / p95 / max
DMP / <18 weeks / 106 / 7 / 68.94 / 32.48 / 4.45 / 0.68 / 0.68 / 16.66 / 38.28 / 107.81 / 212.38 / 462.51
DMP / 18-25 weeks / 106 / 6 / 79.19 / 39.88 / 4.41 / 0.68 / 0.68 / 24.99 / 53.99 / 102.02 / 249.74 / 572.00
DMP / >25 weeks / 105 / 9 / 60.63 / 29.29 / 4.74 / 0.68 / 0.68 / 14.76 / 47.76 / 85.13 / 178.34 / 335.34
DMTP / <18 weeks / 106 / 2 / 65.97 / 34.20 / 3.71 / 0.52 / 3.73 / 15.55 / 36.06 / 85.99 / 211.03 / 483.41
DMTP / 18-25 weeks / 106 / 2 / 91.54 / 41.44 / 3.81 / 0.52 / 5.63 / 21.88 / 41.52 / 102.73 / 307.15 / 873.59
DMTP / >25 weeks / 105 / 1 / 72.59 / 39.98 / 3.32 / 0.52 / 5.49 / 18.93 / 41.87 / 98.16 / 213.28 / 497.07
DMDTP / <18 weeks / 106 / 20 / 4.10 / 1.79 / 3.42 / 0.33 / 0.33 / 0.82 / 1.64 / 4.49 / 11.25 / 73.21
DMDTP / 18-25 weeks / 106 / 23 / 3.89 / 1.62 / 3.41 / 0.33 / 0.33 / 0.70 / 1.42 / 3.60 / 14.35 / 66.64
DMDTP / >25 weeks / 105 / 20 / 5.43 / 2.02 / 3.57 / 0.33 / 0.33 / 0.89 / 2.15 / 4.55 / 16.56 / 155.09
Total DM / <18 weeks / 106 / - / 139.02 / 77.86 / 3.35 / 1.53 / 7.71 / 37.60 / 81.99 / 195.92 / 415.29 / 769.00
Total DM / 18-25 weeks / 106 / - / 174.62 / 96.68 / 3.16 / 1.53 / 13.64 / 51.67 / 98.49 / 190.07 / 558.02 / 1259.58
Total DM / >25 weeks / 105 / - / 138.66 / 83.35 / 3.06 / 6.07 / 9.02 / 45.69 / 94.51 / 172.86 / 387.98 / 762.56
DEP / <18 weeks / 106 / 0 / 24.01 / 10.60 / 3.56 / 0.78 / 1.04 / 5.06 / 9.99 / 24.92 / 104.28 / 365.87
DEP / 18-25 weeks / 106 / 0 / 24.26 / 14.64 / 2.88 / 0.71 / 2.34 / 7.33 / 15.41 / 32.64 / 66.78 / 248.15
DEP / >25 weeks / 105 / 1 / 23.78 / 14.77 / 2.88 / 0.45 / 2.47 / 7.72 / 14.80 / 31.21 / 72.49 / 129.98
DETP / <18 weeks / 106 / 18 / 7.92 / 2.66 / 4.17 / 0.36 / 0.36 / 0.94 / 2.62 / 6.71 / 33.82 / 110.87
DETP / 18-25 weeks / 106 / 9 / 7.18 / 3.31 / 3.70 / 0.06 / 0.36 / 1.47 / 3.26 / 8.23 / 34.23 / 57.64
DETP / >25 weeks / 105 / 14 / 9.82 / 3.90 / 4.10 / 0.36 / 0.36 / 1.88 / 4.53 / 9.88 / 41.53 / 98.11
DEDTP / <18 weeks / 106 / 31 / 0.27 / 0.11 / 3.96 / 0.01 / 0.02 / 0.02 / 0.09 / 0.34 / 0.91 / 3.39
DEDTP / 18-25 weeks / 106 / 26 / 0.37 / 0.14 / 4.14 / 0.02 / 0.02 / 0.05 / 0.13 / 0.36 / 1.65 / 4.01
DEDTP / >25 weeks / 105 / 40 / 0.45 / 0.12 / 5.23 / 0.01 / 0.02 / 0.02 / 0.11 / 0.41 / 1.77 / 6.12
Total DE / <18 weeks / 106 / - / 32.21 / 14.53 / 3.53 / 1.16 / 1.69 / 5.91 / 13.47 / 32.17 / 132.50 / 373.75
Total DE / 18-25 weeks / 106 / - / 31.80 / 19.61 / 2.78 / 0.79 / 4.09 / 9.54 / 19.10 / 36.27 / 90.99 / 294.06
Total DE / >25 weeks / 105 / - / 34.05 / 20.84 / 2.86 / 0.88 / 4.04 / 10.22 / 19.82 / 45.98 / 94.06 / 208.33
Total DAP / <18 weeks / 106 / - / 171.22 / 97.23 / 3.24 / 3.59 / 11.09 / 47.46 / 103.15 / 234.20 / 497.50 / 785.81
Total DAP / 18-25 weeks / 106 / - / 206.41 / 124.18 / 2.84 / 3.37 / 22.28 / 66.12 / 126.95 / 221.01 / 650.53 / 1553.64
Total DAP / >25 weeks / 105 / - / 172.71 / 111.45 / 2.77 / 10.44 / 19.48 / 58.92 / 136.18 / 229.95 / 438.18 / 820.64

Table S2: Pairwise spearman correlation coefficients of metabolite concentrations per mother measured during the 3 periods, variance components and ICCs for DAP metabolite levels for subset of 120 pregnant women from the Generation R cohort (nmol/L)

Metabolite / Correlation coefficients / Variance
Period 1-2 (n=92) / Period 2-3 (n=91) / Period 1-3 (n=92) / Between-person variance / Within-person variance / Total variance / ICC
Corr. / (p) / Corr. / (p) / Corr. / (p)
DMP / 0.20 / (0.053) / 0.20 / (0.054) / 0.26 / (0.012) / 0.70 / 1.58 / 2.28 / 0.31
DMTP / 0.14 / (0.178) / 0.24 / (0.020) / 0.18 / (0.086) / 0.41 / 1.24 / 1.65 / 0.25
DMDTP / 0.13 / (0.217) / 0.14 / (0.193) / 0.14 / (0.172) / 0.22 / 1.33 / 1.55 / 0.14
Total DM / 0.18 / (0.081) / 0.21 / (0.043) / 0.21 / (0.045) / 0.37 / 0.98 / 1.35 / 0.28
DEP / 0.19 / (0.076) / 0.26 / (0.013) / 0.30 / (0.004) / 0.27 / 1.03 / 1.30 / 0.21
DETP / 0.10 / (0.342) / 0.31 / (0.003) / 0.16 / (0.139) / 0.41 / 1.52 / 1.94 / 0.21
DEDTP / 0.32 / (0.002) / 0.38 / (0.000) / 0.18 / (0.085) / 0.64 / 1.58 / 2.22 / 0.29
Total DE / 0.20 / (0.061) / 0.25 / (0.017) / 0.26 / (0.014) / 0.25 / 1.01 / 1.26 / 0.20
Total DAP / 0.20 / (0.057) / 0.25 / (0.018) / 0.23 / (0.030) / 0.32 / 0.86 / 1.18 / 0.27
Range * / 0.10-0.32 / 0.14-0.38 / 0.14-0.30 / 0.22-0.70 / 0.86-1.58 / 1.18-2.28 / 0.14-0.31

* Range as presented is for the 6 individual DAPS as well as the 3 summed groupings.

Table S3: Pairwise spearman correlation coefficients of metabolite concentrations per mother measured during the 3 periods for DAP metabolite levels for subset of 120 pregnant women from the Generation R cohort (nmol/g creatinine), limiting the analyses to only those women with a relatively short duration (≤ median duration) between urine sampling.

Metabolite / Period 1-2 (n=47) * / Period 2-3 (n=64) **
Corr. / (p) / Corr. / (p)
DMP / 0.29 / (0.048) / 0.46 / (0.000)
DMTP / 0.27 / (0.071 / 0.25 / (0.049)
DMDTP / 0.17 / (0.246) / 0.06 / (0.656)
Total DM / 0.21 / (0.158) / 0.34 / (0.006)
DEP / 0.23 / (0.114) / 0.47 / (0.000)
DETP / 0.23 / (0.128) / 0.44 / (0.000)
DEDTP / 0.48 / (0.001) / 0.37 / (0.003)
Total DE / 0.24 / (0.102) / 0.40 / (0.001)
Total DAP / 0.30 / (0.043) / 0.40 / (0.001)
Range *** / 0.17-0.48 / 0.06-0.47

* Medium duration between urine sampling in period 1 and 2 was 7 weeks

** Medium duration between urine sampling in period 2 and 3 was 10 weeks

*** Range as presented is for the 6 individual DAPS as well as the 3 summed groupings.

Table S4: Sensitivity analysis – pairwise spearman correlation coefficients of metabolite concentrations per mother measured during the 3 periods, variance components and ICCs for DAP metabolite levels for subset of 120 pregnant women from the Generation R cohort (nmol/g creatinine), excluding dilute urine specimens (creatinine <100 mg/L)

Metabolite / Correlation coefficients / Variance
Period 1-2 (n=80) / Period 2-3 (n=84) / Period 1-3 (n=80) / Between-person variance / Within-person variance / Total variance / ICC
Corr. / (p) / Corr. / (p) / Corr. / (p)
DMP / 0.31 / (0.005) / 0.39 / (0.000) / 0.20 / (0.072) / 0.47 / 0.97 / 1.44 / 0.32
DMTP / 0.28 / (0.013) / 0.24 / (0.026) / 0.30 / (0.007) / 0.17 / 0.88 / 1.05 / 0.16
DMDTP / 0.23 / (0.045) / 0.07 / (0.502) / 0.26 / (0.022) / 0.18 / 1.14 / 1.32 / 0.13
Total DM / 0.25 / (0.023) / 0.32 / (0.003) / 0.25 / (0.023) / 0.19 / 0.55 / 0.74 / 0.26
DEP / 0.26 / (0.020) / 0.33 / (0.002) / 0.27 / (0.015) / 0.19 / 0.62 / 0.81 / 0.24
DETP / 0.24 / (0.029) / 0.41 / (0.000) / 0.14 / (0.208) / 0.37 / 1.22 / 1.59 / 0.23
DEDTP / 0.47 / (0.000) / 0.43 / (0.000) / 0.31 / (0.005) / 0.81 / 1.27 / 2.08 / 0.39
Total DE / 0.29 / (0.010) / 0.30 / (0.006) / 0.21 / (0.056) / 0.19 / 0.63 / 0.82 / 0.24
Total DAP / 0.29 / (0.008) / 0.34 / (0.002) / 0.30 / (0.008) / 0.17 / 0.44 / 0.61 / 0.27
Range / 0.23-0.47 / 0.07-0.41 / 0.14-0.31 / 0.18-0.81 / 0.44-1.27 / 0.61-2.08 / 0.13-0.39

Brief description of results bivariate determinant analysis of urinary OP pesticide metabolite levels:

The bivariate analyses showed associations for the following parameters: ethnicity, education, smoking during pregnancy, work status, working with pesticides, age mother, food intake. These bivariate models demonstrated that lower total DAP levels were seen in those with secondary education (compared to higher), smoking during pregnancy and paid work or being self-employed, whereas higher levels were seen in those working with pesticides and with increasing age of mother (results not shown). Total DM levels were significantly lower among those who smoked during pregnancy, who had paid work or were self-employed and those with a high potato intake; levels increased with increasing age of the mother. In the case of total DE, higher levels were seen among those with a Dutch ethnicity (compared to other), those working with pesticides, older age of the mother and those with high fruit intake, whereas lower levels were seen in those with secondary education (compared to higher), smoking during pregnancy and high potato intake.
TableS5: Results of multiple regression analysis of determinants of exposure (based on lognormal transformed metabolite levels in nmol/g creatinine); food intake parameters in categories (high versus low)

Total DM (eβ)4 / Total DE (eβ)4 / Total DAP (eβ)4
Combination of determinants1
Between-person variance
Within-person variance / 0.1531 (6%)
0.4975 (-0.5%) / 0.1291 (8%)
0.5907 (0.5%) / 0.1217 (8%)
0.4002 (-0.3%)
Intercept
Ethnicity2 Dutch
European
Other
Education2 Primary
Secondary
Higher
Smoking during pregnancy Until known
Continued
Never
Work status2 Paid work
Self-employed
Other
Working with pesticides Don’t know
Yes
No
Age mother2 <30 years
30-35 years
>35 years
Potatoes3 High
Low
Vegetables3 High
Low
Legumes3 High
Low
Fruits3 High
Low / 141.3 ****
1.55 ***
1.54 *
ref.
1.05
0.84
ref.
0.66 *
0.81
ref.
0.92
0.58 **
ref.
1.52
0.84
ref.
1.11
1.24
ref.
0.81 *
ref.
0.97
ref.
1.14
ref.
0.95
ref. / 28.9 ****
1.16
1.17
ref.
1.06
0.92
ref.
0.76
0.71
ref.
1.14
1.05
ref.
2.97 *
1.42
ref.
1.11
1.16
ref.
0.75 ***
ref.
1.02
ref.
1.03
ref.
1.27 *
ref. / 187.5 ****
1.40 **
1.37
ref.
1.09
0.84
ref.
0.69 *
0.81
ref.
0.94
0.64 *
ref.
1.66
0.98
ref.
1.12
1.23
ref.
0.82 **
ref.
0.98
ref.
1.13
ref.
0.99
ref.

1 Based on part of the dataset with complete data, 241 (out of 318) measurements for 91 (out of 120) women

2 Based on combination of categories, to limit the number of categories within each parameter in the determinant analysis and have a relevant number of individuals in each category

3 The continuous food intake variables were divided into categories ‘low’ and ‘high’ based on the median concentration, which was 45 g/day for potatoes and other tubers, 139 g/day for vegetables, 1.2 g/day for legumes and 193 g/day for fruits.

4 Between brackets the percentage of explained between- and within-person variability. Please note that the exponentiated coefficients (eβ) are presented here, as the analysis was performed on lognormal transformed data.

Ref: reference category

**** p<0.0001, ***0.0001<p<0.05, ** 0.05<p<0.10, * 0.10<p<0.20

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