Socio-Economic Status and Health: Evaluation of Human Biomonitored Chemical Exposure to Per- and Polyfluorinated Substances across Status

Abstract

Research on the environment, health, and well-being nexus (EHWB) is shifting from a silo toward a systemic approach that includes the socio-economic context. To disentangle further the complex interplay between the socio-exposome and internal chemical exposure, we performed a meta-analysis of human biomonitoring (HBM) studies with internal exposure data on per-and polyfluoroalkyl substances (PFASs) and detailed information on risk factors, including descriptors of socio-economic status (SES) of the study population. PFASs are persistent in nature, and some have endocrine-disrupting properties. Individual studies have shown that HBM biomarker concentrations of PFASs generally increase with SES indicators, e.g., for income. Based on a meta-analysis (five studies) of the associations between PFASs and SES indicators, the magnitude of the association could be estimated. For the SES indicator income, changes in income were expressed by a factor change, which was corrected by the Gini coefficient to take into account the differences in income categories between studies, and the income range between countries. For the SES indicator education, we had to conclude that descriptors (<college, x years of study, etc.) differed too widely between studies to perform a meta-analysis. Therefore, the use of the uniform ISCED (International Standard Classification of Education) is recommended in future studies. The meta-analysis showed that a higher income is associated with a higher internal exposure to PFASs (PFOS or perfluorooctanesulfonic acid, PFOA or perfluorooctanoic acid, PFNA or perfluorononanoic acid, PFHxS or perfluorohexane sulfonate). This is opposite to the environmental justice hypothesis, referring to an inequitable distribution of detrimental environmental effects toward poor and minority communities by a practice or policy. With a doubling of the income, internal exposure increased on average by 10%–14%. Possible explanations for this difference are given, e.g., underlying differences in diet. However, other sources can also contribute, and the exact causes of SES-related differences in PFAS concentrations remain unclear. Studies are needed that include social descriptors together with lifestyle and dietary information as explanatory variables for internal chemical exposure levels. This will help clarify the underlying factors that link SES with inequity to environmental exposures, and will raise awareness and knowledge to strengthen the capacities of people and communities to advocate chemical exposure reduction in order to reduce this health inequity.

Environmental chemical exposures among Greenlandic children in relation to diet and residence

“…Furthermore, household dust was found not to contribute to PFAS exposure among Alaska natives [45]. In other settings, environmental exposures have also been associated with socioeconomic status (SES) [46], but SES is unlikely to be a major predictor of exposure among Greenlandic children. Although there are variations in SES within the Greenlandic population, the differences are less pronounced than in, e.g.…”

Harnessing Electronic Health Records to Study Emerging Environmental Disasters: A Proof of Concept with Perfluoralkyl Substances (PFAS)

“…A meta-analysis found that with a doubling of income the exposure to PFAS increased on average 10-14% 49 . This is contrary to the typical environmental justice hypothesis that higher income individuals have lower exposure to pollutants in general 49 . Many theories exist to explain this counter-intuitive result; some conclude that it could be due to routes of exposures (e.g., dental floss) or perhaps a result of the way many prior studies were conducted.…”

“…In this proof-of-concept, we ignore the socioeconomic factors because our desire was to replicate prior research on the health risks associated with PFAS exposure and the prior research often ignores socioeconomic co-contributors. A meta-analysis found that with a doubling of income the exposure to PFAS increased on average 10-14% 49 . This is contrary to the typical environmental justice hypothesis that higher income individuals have lower exposure to pollutants in general 49 .…”

Endocrine Disruptor Potential of Short- and Long-Chain Perfluoroalkyl Substances (PFASs)—A Synthesis of Current Knowledge with Proposal of Molecular Mechanism

“…In their meta-analysis of bio-monitoring studies (internal exposure to PFASs associated with descriptors of social and economic status). Buekers et al [ 204 ] concluded that education level could not be analyzed because of excessive range of descriptors themselves. However, they demonstrated that increased income was associated with internal exposure to PFOA, PFOS and short-chain PFASs such as PFNA and PFHxS.…”