Longitudinal trends of per- and polyfluoroalkyl substances in children's serum
Jani Koponen1, Kerstin Winkens2, Riikka Airaksinen1
1Department of Health Security, National Institute for Health and Welfare (THL), FI-70150 Kuopio, Finland.
Insights
Childhood exposure to per- and polyfluoroalkyl substances (PFASs) is concerning. Body burdens, not just serum concentrations, are crucial for understanding long-term PFAS exposure in children.
Area of Science:
- Environmental Health
- Toxicology
- Pediatrics
Background:
- Early life exposure to per- and polyfluoroalkyl substances (PFASs) is linked to negative health outcomes.
- Longitudinal data on PFAS exposure in children is limited, particularly for those with background exposure.
Purpose of the Study:
- To investigate longitudinal exposure trends of per- and polyfluoroalkyl substances (PFASs) in children.
- To compare serum concentrations and body burdens of PFASs over time.
- To evaluate associations between PFAS levels and factors like sex, breastfeeding, BMI, and indoor environmental concentrations.
Main Methods:
- Longitudinal blood sampling from 54 Finnish children between 1 and 10.5 years of age.
- Analysis of 20 different PFASs using serum concentration measurements.
- Calculation of PFAS body burdens by integrating serum concentration, volume of distribution, and body weight.
Main Results:
- Serum concentrations of key PFASs (PFOS, PFOA, PFNA, PFHxS) significantly decreased with age.
- PFAS body burdens remained stable or increased with age, except for PFOA in females, indicating ongoing exposure.
- Breastfeeding duration showed a positive correlation with serum PFAS levels at one year of age.
Conclusions:
- Longitudinal serum PFAS concentrations can be misleading due to growth dilution and temporal changes.
- PFAS body burdens provide a more accurate reflection of cumulative exposure from early life through adolescence.
- Understanding body burdens is essential for assessing the true impact of environmental PFAS exposure on child health.
Abstract:
Studies suggest negative health impacts from early life exposure to per- and polyfluoroalkyl substances (PFASs). However, information on longitudinal exposure to PFASs during childhood is scarce for background-exposed individuals. This study sought to fill this gap by investigating children's longitudinal exposure trends through measurement of PFAS serum concentrations and calculation of body burdens (μg, total in body). Blood of 54 Finnish children was sampled 2005-2015 and analyzed for 20 PFASs at 1, 6 and 10.5 years of age. The body burden was calculated by multiplying the serum concentration by the volume of distribution and the bodyweight for each individual. Associations between serum concentrations or body burdens and parameters, such as sex, breastfeeding duration, body mass index as well as indoor dust and air PFAS concentrations, were evaluated. Serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) decreased significantly (p < 0.001) with age. In contrast to serum concentrations, body burdens stayed unchanged or even increased significantly (p < 0.05), except for PFOA in female children. Breastfeeding duration was positively correlated (p < 0.001) with serum concentrations of PFHxS, PFOS, PFOA and PFNA at 1 year of age. Some associations were found at 10.5 years with sex and indoor PFAS concentrations. Observations of longitudinal decreasing trends of serum concentrations can be misleading for understanding exposure levels from external media during childhood, as the serum concentration is influenced by parallel temporal changes and growth dilution. Body burdens account for growth dilution and thus better reflect differences in early-life to adolescence exposure than serum concentrations.
