title: Enhanced elimination of perfluorooctane sulfonic acid by menstruating women: evidence from population-based pharmacokinetic modeling.
abstract: Human biomonitoring studies have shown that concentrations of perfluorooctane sulfonic acid (PFOS) in men are higher than in women. We investigate sex differences in elimination of PFOS by fitting a population-based pharmacokinetic model to six cross-sectional data sets from 1999 to 2012 from the US National Health and Nutrition Examination Survey (NHANES) and derive human first-order elimination rate constants (kE) and corresponding elimination half-lives (t1/2) for PFOS, where t1/2 = ln 2/kE. We use a modified version of the Ritter population-based pharmacokinetic model and derive elimination rate constants separately for men and women. The model accounts for population-average lifetime changes in PFOS intake, body weight, and menstruation rate. We compare the model-derived elimination rate constant for hypothetical nonmenstruating women to the elimination rate constant for men and women when menstruation is included as a loss process to evaluate the hypothesis that loss of PFOS by menstruation is an important process for women. The modeled elimination half-life for men is 4.7 years, and the modeled elimination half-life for women when excluding losses from menstruation is 3.7 years. The elimination half-life for women when menstruation is included in the model is 4.0 years. Thus, menstruation accounts for 30% of the discrepancy in elimination of PFOS between men and women. The remaining discrepancy is likely due to other sex-specific elimination routes that are not considered in our modeling.
authors.affiliation: Department of Applied Environmental Science (ITM), Stockholm University , Svante Arrhenius väg 8, SE-10691, Stockholm, Sweden.
authors.forename: Fiona
authors.initials: F
authors.lastname: Wong
authors.forename: Matthew
authors.initials: M
authors.lastname: MacLeod
authors.forename: Jochen F
authors.initials: JF
authors.lastname: Mueller
authors.forename: Ian T
authors.initials: IT
authors.lastname: Cousins
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017738:Alkanesulfonic Acids / Q000493:pharmacokinetics*; D001835:Body Weight; D002648:Child; D003430:Cross-Sectional Studies; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000493:pharmacokinetics*; D005260:Female; D005466:Fluorocarbons / Q000493:pharmacokinetics*; D006207:Half-Life; D006801:Humans; D008297:Male; D008598:Menstruation; D008875:Middle Aged; D008962:Models, Theoretical; D009749:Nutrition Surveys; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: D017738:Alkanesulfonic Acids; D004785:Environmental Pollutants; D005466:Fluorocarbons; C076994:perfluorooctane sulfonic acid