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Characterization of phthalate exposure among pregnant women assessed by repeat air and urine samples.

Adibi JJ, Whyatt RM, Williams PL, Calafat AM, Camann D, Herrick R, Nelson H, Bhat HK, Perera FP, Silva MJ, Hauser R - Environ. Health Perspect. (2008)

Bottom Line: Mixed-effects models were fit to evaluate reproducibility via intraclass correlation coefficients (ICC).In women sampled late in pregnancy, specific gravity appeared to be more effective than creatinine in adjusting for urine dilution.A single indoor air sample may be sufficient to characterize phthalate exposure in the home, whereas urinary phthalate biomarkers should be sampled longitudinally during pregnancy to minimize exposure misclassification.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA.

ABSTRACT

Background: Although urinary concentrations of phthalate metabolites are frequently used as biomarkers in epidemiologic studies, variability during pregnancy has not been characterized.

Methods: We measured phthalate metabolite concentrations in spot urine samples collected from 246 pregnant Dominican and African-American women. Twenty-eight women had repeat urine samples collected over a 6-week period. We also analyzed 48-hr personal air samples (n = 96 women) and repeated indoor air samples (n = 32 homes) for five phthalate diesters. Mixed-effects models were fit to evaluate reproducibility via intraclass correlation coefficients (ICC). We evaluated the sensitivity and specificity of using a single specimen versus repeat samples to classify a woman's exposure in the low or high category.

Results: Phthalates were detected in 85-100% of air and urine samples. ICCs for the unadjusted urinary metabolite concentrations ranged from 0.30 for mono-ethyl phthalate to 0.66 for monobenzyl phthalate. For indoor air, ICCs ranged from 0.48 [di-2-ethylhexyl phthalate (DEHP)] to 0.83 [butylbenzyl phthalate (BBzP)]. Air levels of phthalate diesters correlated with their respective urinary metabolite concentrations for BBzP (r = 0.71), di-isobutyl phthalate (r = 0.44), and diethyl phthalate (DEP; r = 0.39). In women sampled late in pregnancy, specific gravity appeared to be more effective than creatinine in adjusting for urine dilution.

Conclusions: Urinary concentrations of DEP and DEHP metabolites in pregnant women showed lower reproducibility than metabolites for di-n-butyl phthalate and BBzP. A single indoor air sample may be sufficient to characterize phthalate exposure in the home, whereas urinary phthalate biomarkers should be sampled longitudinally during pregnancy to minimize exposure misclassification.

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Summary of Spearman coefficients of correlation between phthalate concentrations measured in environmental and biologic matrices.aUnadjusted for urinary dilution (data not available). bAdjusted for specific gravity. *p < 0.20. **p < 0.05.
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f2-ehp0116-000467: Summary of Spearman coefficients of correlation between phthalate concentrations measured in environmental and biologic matrices.aUnadjusted for urinary dilution (data not available). bAdjusted for specific gravity. *p < 0.20. **p < 0.05.

Mentions: We found no correlation between phthalate metabolite concentrations measured in urine samples collected from mothers and their newborns approximately 1 day after delivery. For three metabolites, there was a suggestive inverse correlation between the geometric mean of 19 mothers’ samples (two to five urine samples collected over 8 weeks before delivery) with their newborns’ urinary metabolites measured 1 day after delivery (MEHP, r = −0.31, p = 0.19; MCPP, r = −0.39, p = 0.09; MBzP, r = −0.29, p = 0.22) (Figure 2).


Characterization of phthalate exposure among pregnant women assessed by repeat air and urine samples.

Adibi JJ, Whyatt RM, Williams PL, Calafat AM, Camann D, Herrick R, Nelson H, Bhat HK, Perera FP, Silva MJ, Hauser R - Environ. Health Perspect. (2008)

Summary of Spearman coefficients of correlation between phthalate concentrations measured in environmental and biologic matrices.aUnadjusted for urinary dilution (data not available). bAdjusted for specific gravity. *p < 0.20. **p < 0.05.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2291011&req=5

f2-ehp0116-000467: Summary of Spearman coefficients of correlation between phthalate concentrations measured in environmental and biologic matrices.aUnadjusted for urinary dilution (data not available). bAdjusted for specific gravity. *p < 0.20. **p < 0.05.
Mentions: We found no correlation between phthalate metabolite concentrations measured in urine samples collected from mothers and their newborns approximately 1 day after delivery. For three metabolites, there was a suggestive inverse correlation between the geometric mean of 19 mothers’ samples (two to five urine samples collected over 8 weeks before delivery) with their newborns’ urinary metabolites measured 1 day after delivery (MEHP, r = −0.31, p = 0.19; MCPP, r = −0.39, p = 0.09; MBzP, r = −0.29, p = 0.22) (Figure 2).

Bottom Line: Mixed-effects models were fit to evaluate reproducibility via intraclass correlation coefficients (ICC).In women sampled late in pregnancy, specific gravity appeared to be more effective than creatinine in adjusting for urine dilution.A single indoor air sample may be sufficient to characterize phthalate exposure in the home, whereas urinary phthalate biomarkers should be sampled longitudinally during pregnancy to minimize exposure misclassification.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA.

ABSTRACT

Background: Although urinary concentrations of phthalate metabolites are frequently used as biomarkers in epidemiologic studies, variability during pregnancy has not been characterized.

Methods: We measured phthalate metabolite concentrations in spot urine samples collected from 246 pregnant Dominican and African-American women. Twenty-eight women had repeat urine samples collected over a 6-week period. We also analyzed 48-hr personal air samples (n = 96 women) and repeated indoor air samples (n = 32 homes) for five phthalate diesters. Mixed-effects models were fit to evaluate reproducibility via intraclass correlation coefficients (ICC). We evaluated the sensitivity and specificity of using a single specimen versus repeat samples to classify a woman's exposure in the low or high category.

Results: Phthalates were detected in 85-100% of air and urine samples. ICCs for the unadjusted urinary metabolite concentrations ranged from 0.30 for mono-ethyl phthalate to 0.66 for monobenzyl phthalate. For indoor air, ICCs ranged from 0.48 [di-2-ethylhexyl phthalate (DEHP)] to 0.83 [butylbenzyl phthalate (BBzP)]. Air levels of phthalate diesters correlated with their respective urinary metabolite concentrations for BBzP (r = 0.71), di-isobutyl phthalate (r = 0.44), and diethyl phthalate (DEP; r = 0.39). In women sampled late in pregnancy, specific gravity appeared to be more effective than creatinine in adjusting for urine dilution.

Conclusions: Urinary concentrations of DEP and DEHP metabolites in pregnant women showed lower reproducibility than metabolites for di-n-butyl phthalate and BBzP. A single indoor air sample may be sufficient to characterize phthalate exposure in the home, whereas urinary phthalate biomarkers should be sampled longitudinally during pregnancy to minimize exposure misclassification.

Show MeSH
Related in: MedlinePlus