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Exogenous and endogenous determinants of blood trihalomethane levels after showering.

Backer LC, Lan Q, Blount BC, Nuckols JR, Branch R, Lyu CW, Kieszak SM, Brinkman MC, Gordon SM, Flanders WD, Romkes M, Cantor KP - Environ. Health Perspect. (2008)

Bottom Line: We did not observe the clustering of blood THM concentrations observed in our earlier study.We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering.For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001).

View Article: PubMed Central - PubMed

Affiliation: National Center for Environmental Health, Centers for Disease Control and Prevention, Chamblee, GA 30341, USA. lfb9@cdc.gov <lfb9@cdc.gov>

ABSTRACT

Background: We previously conducted a study to assess whether household exposures to tap water increased an individual's internal dose of trihalomethanes (THMs). Increases in blood THM levels among subjects who showered or bathed were variable, with increased levels tending to cluster in two groups.

Objectives: Our goal was to assess the importance of personal characteristics, previous exposures, genetic polymorphisms, and environmental exposures in determining THM concentrations in blood after showering.

Methods: One hundred study participants completed a health symptom questionnaire, a 48-hr food and water consumption diary, and took a 10-min shower in a controlled setting. We examined THM levels in blood samples collected at baseline and 10 and 30 min after the shower. We assessed the significance of personal characteristics, previous exposures to THMs, and specific gene polymorphisms in predicting postshower blood THM concentrations.

Results: We did not observe the clustering of blood THM concentrations observed in our earlier study. We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering. For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001). Personal characteristics, previous exposures to THMs, and specific polymorphisms in CYP2D6 and GSTT1 genes were significant predictors of both baseline and postshowering blood THM concentrations as well as of changes in THM concentrations associated with showering.

Conclusion: The inclusion of information about individual physiologic characteristics and environmental measurements would be valuable in future studies to assess human health effects from exposures to THMs in tap water.

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Related in: MedlinePlus

THM concentrations in whole blood at baseline and 10 min postshowering. The capped bars are the minimum and maximum, the box extents indicate the 25th and 75th percentiles, the line inside the box marks the 50th percentile, and the + indicates the mean (n = 99).
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f2-ehp0116-000057: THM concentrations in whole blood at baseline and 10 min postshowering. The capped bars are the minimum and maximum, the box extents indicate the 25th and 75th percentiles, the line inside the box marks the 50th percentile, and the + indicates the mean (n = 99).

Mentions: THM concentrations in blood samples and the changes in concentration (10 min postshower minus baseline) are presented in Table 2. The blood THM data for one study participant seemed anomalous (> 2 SDs from the sample means at baseline and after showering) and thus were removed from these analyses. Blood THM levels are presented in Figure 2. THM concentrations measured 10 min after the shower were log-normally distributed.


Exogenous and endogenous determinants of blood trihalomethane levels after showering.

Backer LC, Lan Q, Blount BC, Nuckols JR, Branch R, Lyu CW, Kieszak SM, Brinkman MC, Gordon SM, Flanders WD, Romkes M, Cantor KP - Environ. Health Perspect. (2008)

THM concentrations in whole blood at baseline and 10 min postshowering. The capped bars are the minimum and maximum, the box extents indicate the 25th and 75th percentiles, the line inside the box marks the 50th percentile, and the + indicates the mean (n = 99).
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2199304&req=5

f2-ehp0116-000057: THM concentrations in whole blood at baseline and 10 min postshowering. The capped bars are the minimum and maximum, the box extents indicate the 25th and 75th percentiles, the line inside the box marks the 50th percentile, and the + indicates the mean (n = 99).
Mentions: THM concentrations in blood samples and the changes in concentration (10 min postshower minus baseline) are presented in Table 2. The blood THM data for one study participant seemed anomalous (> 2 SDs from the sample means at baseline and after showering) and thus were removed from these analyses. Blood THM levels are presented in Figure 2. THM concentrations measured 10 min after the shower were log-normally distributed.

Bottom Line: We did not observe the clustering of blood THM concentrations observed in our earlier study.We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering.For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001).

View Article: PubMed Central - PubMed

Affiliation: National Center for Environmental Health, Centers for Disease Control and Prevention, Chamblee, GA 30341, USA. lfb9@cdc.gov <lfb9@cdc.gov>

ABSTRACT

Background: We previously conducted a study to assess whether household exposures to tap water increased an individual's internal dose of trihalomethanes (THMs). Increases in blood THM levels among subjects who showered or bathed were variable, with increased levels tending to cluster in two groups.

Objectives: Our goal was to assess the importance of personal characteristics, previous exposures, genetic polymorphisms, and environmental exposures in determining THM concentrations in blood after showering.

Methods: One hundred study participants completed a health symptom questionnaire, a 48-hr food and water consumption diary, and took a 10-min shower in a controlled setting. We examined THM levels in blood samples collected at baseline and 10 and 30 min after the shower. We assessed the significance of personal characteristics, previous exposures to THMs, and specific gene polymorphisms in predicting postshower blood THM concentrations.

Results: We did not observe the clustering of blood THM concentrations observed in our earlier study. We found that environmental THM concentrations were important predictors of blood THM concentrations immediately after showering. For example, the chloroform concentration in the shower stall air was the most important predictor of blood chloroform levels 10 min after the shower (p < 0.001). Personal characteristics, previous exposures to THMs, and specific polymorphisms in CYP2D6 and GSTT1 genes were significant predictors of both baseline and postshowering blood THM concentrations as well as of changes in THM concentrations associated with showering.

Conclusion: The inclusion of information about individual physiologic characteristics and environmental measurements would be valuable in future studies to assess human health effects from exposures to THMs in tap water.

Show MeSH
Related in: MedlinePlus