Two-year follow-up biomonitoring pilot study of residents’ and controls’ PFC plasma levels after PFOA reduction in public water system in Arnsberg, Germany

Brede, Edna; Wilhelm, Michael; Göen, Thomas; Müller, Johannes; Rauchfuss, Knut; Kraft, Martin; Hölzer, Jürgen

doi:10.1016/j.ijheh.2010.03.007

Cited by 133 publications

(61 citation statements)

References 19 publications

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“…Two years of follow-up of another residential cohort exposed to PFOA via drinking water in Arnsberg, Germany yielded a geometric mean half-life estimate of 3.26 years, using two serum samples each for 65 residents, including both children and adults. 9 These residents had lower exposures than the US residential cohort, with strata-specific baseline geometric mean PFOA serum concentrations ranging from 22.1 ng/ml for children to 25.3 ng/ml for men. A previous study of a retired US occupational cohort reported an average PFOA half-life estimate of 3.8 years from 5 years of follow-up with a baseline median serum PFOA concentration of 408 ng/ml and up to eight measurements per participant.…”

mentioning

confidence: 84%

“…For errors that are small relative to the predicted log biomarker concentrations, the denominator is approximately equal to c 1 so E 1 k % c3 c1 , the approximation used in Eqs. (8) and (9).…”

Section: Conflict Of Interestmentioning

confidence: 99%

“…(1), provided that the covariates have constant multiplicative effects on serum concentrations over time. 7 Studies of post-shift workers, 2,5 retired workers, 4 fasting subjects, 6 and subjects undergoing exposure interventions 7,9 have used regression of log biomarker concentrations on time to estimate elimination rate constants and corresponding half-lives for environmental contaminants. However, Eq.…”

Section: Introductionmentioning

confidence: 99%

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Bias in half-life estimates using log concentration regression in the presence of background exposures, and potential solutions

Bartell

2012

J Expo Sci Environ Epidemiol

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Regression of log serum concentrations or log urine concentrations on time elapsed after primary exposure ceases is a common method for estimating the elimination rates and corresponding half-lives for environmental contaminants. However, this method produces bias in the presence of ongoing background exposures. A general formula for the amount of bias introduced by background exposures under any single compartment pharmacokinetic model is derived here, and simpler expressions and graphical results are presented for the special case of regularly spaced biomarker measurements. The formulas are also applied to evaluate the potential bias from background exposures in recently published half-life estimates for perfluorooctanoate. These published half-lives are likely to be overestimated because of bias from background exposures, by about 1 --26%. Background exposures can contribute substantial bias to half-life estimates based on longer follow-up times, even when the background contribution constitutes a small fraction of total exposure at baseline. ( Journal of Exposure Science and Environmental Epidemiology INTRODUCTIONRegression of log serum concentrations on time is a long practiced method for estimating first-order elimination rates of contaminants and drugs after exposure ceases. 1 --8 Similar methods are used for urine concentrations and other biomarkers. After exposure ceases, the first-order elimination implies the following equation:where C t is the serum concentration at time t, C 0 is the serum concentration at baseline (time 0), and k is the elimination rate constant. Therefore, if the errors are independent, normally distributed, and homoscedastic, the slope from linear regression of log concentrations reliably estimates Àk, and the intercept estimates ln C 0 . The apparent half-life t 1/2 ¼ ln(2)/k. Adjustment for covariate effects on the serum concentrations is easily handled by adding additional terms to the model on the right hand side of Eq.(1), provided that the covariates have constant multiplicative effects on serum concentrations over time. 7 Studies of post-shift workers, 2,5 retired workers, 4 fasting subjects, 6 and subjects undergoing exposure interventions 7,9 have used regression of log biomarker concentrations on time to estimate elimination rate constants and corresponding half-lives for environmental contaminants. However, Eq. (1) does not apply when any of the exposures are continuing, as occurs in many studies of environmental contaminants because of ongoing background exposures. With a constant background exposure that continues after some larger exposure ceases, as might be expected for retired workers, residents who leave a contaminated community, or anyone who has undergone an exposure intervention that eliminates most but not all exposure to a toxicant, the first-order elimination model implies the following:where C N is the background contribution to the serum concentration at any point in time. 10 When C N is very small relative to C 0 , Eqs. (1) and (2) are approximately eq...

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confidence: 84%

Section: Conflict Of Interestmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bias in half-life estimates using log concentration regression in the presence of background exposures, and potential solutions

Bartell

2012

J Expo Sci Environ Epidemiol

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“…PFCs are distributed mainly to the liver and blood where they bind to serum proteins, mainly albumin (Han et al 2003;Jones et al 2003), and they are poorly eliminated in humans and have serum half-lives between 2 and 9 years (Lau et al 2007;Olsen et al 2007;Bartell et al 2010;Brede et al 2010;Seals et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Determinants of maternal and fetal exposure and temporal trends of perfluorinated compounds

Ode

Rylander

Lindh

et al. 2013

Environ Sci Pollut Res

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“…And recent studies strongly indicate that PFOA levels increase with age [105,106]. Elimination half-lives of PFOA in humans of 3.5 [64] or 3.26 [107] years indicate the bioaccumulation potential of PFOA.…”

Section: Assessment Of the Bioaccumulation Potentialmentioning

confidence: 99%

Perfluorooctanoic acid (PFOA) — main concerns and regulatory developments in Europe from an environmental point of view

et al. 2012

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Background: Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are the most investigated substances of the group of per-and polyfluorinated chemicals (PFCs). Whereas for PFOS regulatory measures are already in force on international level (inclusion in Stockholm Convention on Persistent Organic Pollutants) such activities are missing for PFOA. The environmental concerns of PFOA, which are summarized in the present study, underline the necessity of regulatory measures on an international level for PFOA. Since it seems more likely to agree on a regulation within the European Union first, a regulatory strategy based on the European chemicals regulation REACH (EC No. 1907, is discussed in the present study.

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Two-year follow-up biomonitoring pilot study of residents’ and controls’ PFC plasma levels after PFOA reduction in public water system in Arnsberg, Germany

Cited by 133 publications

References 19 publications

Bias in half-life estimates using log concentration regression in the presence of background exposures, and potential solutions

Bias in half-life estimates using log concentration regression in the presence of background exposures, and potential solutions

Determinants of maternal and fetal exposure and temporal trends of perfluorinated compounds

Perfluorooctanoic acid (PFOA) — main concerns and regulatory developments in Europe from an environmental point of view

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