Comment on “Enhanced Elimination of Perfluorooctanesulfonic Acid by Menstruating Women: Evidence from Population-Based Pharmacokinetic Modeling”

Rubella immunity and serum perfluoroalkyl substances: Sex and analytic strategy

“…Table 1 shows that the differences in levels of rubella titres between men and women are significant. This apparent discrepancy could be partly due to the previously mentioned sex differences related to menstrual cycles [ 22 – 26 ] and parity. If women have lower concentrations of PFASs to begin with, it may explain why the subsequent stratified analyses controlling for parity in women show a more pronounced effect of PFOA than PFOS on rubella titres in men.…”

“…The authors have found sex specific physiological responses associated with PFASs in their earlier work [ 2 ] but have not examined ethnicity differences. Based on previously published data showing lower PFAS concentrations in menstruating women [ 22 – 26 ] that may be as great as 30% or more [ 25 – 26 ], the hypothesis of this paper was that sex is an effect modifier and that by not stratifying analyses, there is a risk that overall results will mask true associations. Given the importance that a reduction of immunity to rubella in women might pose, this seemed especially important to test.…”

Oral contraceptive use as a determinant of plasma concentrations of perfluoroalkyl substances among women in the Norwegian Mother and Child Cohort (MoBa) study

“…The most obvious mechanism through which OCs might increase body burden of PFAS concentrations is alteration of menstruation as menstrual fluid loss is an important excretion route for PFASs (14, 34). OCs in use today have been associated with a 44% reduction in menstrual fluid loss among normal women (35) and 64% reduction in menstrual fluid loss in women with heavy or prolonged menstrual bleeding (36).…”

Predicting risks in an increasingly complex world

“…The NHANES data are cross-sectional and, therefore, the estimates of t1/2 required fitting the data to age patterns of PFOS intake. An improved fit to the data for females was achieved when estimated losses of PFOS in menstrual fluids were considered, suggesting that menstrual loss of PFOS may account for some, but not all, of the sex difference in the elimination rate (Verner and Longnecker 2015;Wong et al 2015). Li et al (2018) also found apparent sex differences in PFOS elimination in male and female residents in Sweden exposed to contaminated drinking water.…”

“…• Loss of PFHxS in menstrual blood was included in the human female model. This is represented as a direct loss of loss of 42.5 mL blood (25 mL plasma) per month (Verner and Longnecker 2015). Kim et al (2018) does not report an evaluation of the human model.…”