Limits...
Prenatal PCB exposure and thymus size at birth in neonates in Eastern Slovakia.

Park HY, Hertz-Picciotto I, Petrik J, Palkovicova L, Kocan A, Trnovec T - Environ. Health Perspect. (2008)

Bottom Line: Prenatal PCB exposure was associated with a smaller thymic index at birth [beta= -36 (natural log-transformed; nanograms per gram lipids); p = 0.047].Male sex, later gestational age, larger birth weight z-score, and Roma ethnicity were associated with a larger thymic index, whereas respiratory illness was associated with a lower thymic index.This study provides the first evidence to date that PCB exposure in neonates is associated with a smaller thymic volume, suggesting possible impaired immunologic development.

View Article: PubMed Central - PubMed

Affiliation: Division of Epidemiology, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA 95616, USA.

ABSTRACT

Background: Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants, for which animal studies demonstrate immunotoxic effects, including thymic atrophy and suppressed immune responses; human investigations of similar end points are sparse. The thymus is essential for the differentiation and maturation of T-cell lymphocytes.

Objectives: The objective of this study was to examine the association between prenatal PCB exposures and estimated thymus volume in infants from eastern Slovakia, a region where PCBs were produced until 1984.

Methods: Mothers were enrolled at delivery, and maternal blood samples were collected for analysis of 15 PCB congeners, p,p'-DDT [1,1,1-trichloro-2,2'-bis(p-chlorophenyl)ethane], and p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene]. Each mother was interviewed to obtain information on sociodemographic characteristics, past pregnancies, occupational history, medication history, and living environment. Neonatal thymus volume was estimated using ultrasound measurements on the third or fourth day after birth. Thymic index was calculated on 982 newborns from mothers with PCB measurements. We developed a predictive model of the natural log of the thymic index using multiple linear regression with covariates selected from the bivariate analyses.

Results: Prenatal PCB exposure was associated with a smaller thymic index at birth [beta= -36 (natural log-transformed; nanograms per gram lipids); p = 0.047]. District of residence and delivery also predicted thymic index. Male sex, later gestational age, larger birth weight z-score, and Roma ethnicity were associated with a larger thymic index, whereas respiratory illness was associated with a lower thymic index.

Conclusions: This study provides the first evidence to date that PCB exposure in neonates is associated with a smaller thymic volume, suggesting possible impaired immunologic development.

Show MeSH

Related in: MedlinePlus

Scatterplot of residuals for thymic index in relation to log maternal serum PCBs after adjusting for other predictors.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2199273&req=5

f1-ehp0116-000104: Scatterplot of residuals for thymic index in relation to log maternal serum PCBs after adjusting for other predictors.

Mentions: Scatterplots of residuals (the difference between the observed thymic index values and those predicted by the regression equation) for thymic index were plotted from the multivariate model that included all variables in the final model except PCBs. Figure 1 shows the partial residuals from a model that included only the covariates as predictors, as well as the best-fitting line after inclusion of log-transformed PCBs, demonstrating the decreasing trend of the log-transformed thymic index with increasing exposure. The SAS statistical package was used for analysis (version 9.1; SAS Institute Inc., Cary, NC, USA).


Prenatal PCB exposure and thymus size at birth in neonates in Eastern Slovakia.

Park HY, Hertz-Picciotto I, Petrik J, Palkovicova L, Kocan A, Trnovec T - Environ. Health Perspect. (2008)

Scatterplot of residuals for thymic index in relation to log maternal serum PCBs after adjusting for other predictors.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2199273&req=5

f1-ehp0116-000104: Scatterplot of residuals for thymic index in relation to log maternal serum PCBs after adjusting for other predictors.
Mentions: Scatterplots of residuals (the difference between the observed thymic index values and those predicted by the regression equation) for thymic index were plotted from the multivariate model that included all variables in the final model except PCBs. Figure 1 shows the partial residuals from a model that included only the covariates as predictors, as well as the best-fitting line after inclusion of log-transformed PCBs, demonstrating the decreasing trend of the log-transformed thymic index with increasing exposure. The SAS statistical package was used for analysis (version 9.1; SAS Institute Inc., Cary, NC, USA).

Bottom Line: Prenatal PCB exposure was associated with a smaller thymic index at birth [beta= -36 (natural log-transformed; nanograms per gram lipids); p = 0.047].Male sex, later gestational age, larger birth weight z-score, and Roma ethnicity were associated with a larger thymic index, whereas respiratory illness was associated with a lower thymic index.This study provides the first evidence to date that PCB exposure in neonates is associated with a smaller thymic volume, suggesting possible impaired immunologic development.

View Article: PubMed Central - PubMed

Affiliation: Division of Epidemiology, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA 95616, USA.

ABSTRACT

Background: Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants, for which animal studies demonstrate immunotoxic effects, including thymic atrophy and suppressed immune responses; human investigations of similar end points are sparse. The thymus is essential for the differentiation and maturation of T-cell lymphocytes.

Objectives: The objective of this study was to examine the association between prenatal PCB exposures and estimated thymus volume in infants from eastern Slovakia, a region where PCBs were produced until 1984.

Methods: Mothers were enrolled at delivery, and maternal blood samples were collected for analysis of 15 PCB congeners, p,p'-DDT [1,1,1-trichloro-2,2'-bis(p-chlorophenyl)ethane], and p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene]. Each mother was interviewed to obtain information on sociodemographic characteristics, past pregnancies, occupational history, medication history, and living environment. Neonatal thymus volume was estimated using ultrasound measurements on the third or fourth day after birth. Thymic index was calculated on 982 newborns from mothers with PCB measurements. We developed a predictive model of the natural log of the thymic index using multiple linear regression with covariates selected from the bivariate analyses.

Results: Prenatal PCB exposure was associated with a smaller thymic index at birth [beta= -36 (natural log-transformed; nanograms per gram lipids); p = 0.047]. District of residence and delivery also predicted thymic index. Male sex, later gestational age, larger birth weight z-score, and Roma ethnicity were associated with a larger thymic index, whereas respiratory illness was associated with a lower thymic index.

Conclusions: This study provides the first evidence to date that PCB exposure in neonates is associated with a smaller thymic volume, suggesting possible impaired immunologic development.

Show MeSH
Related in: MedlinePlus