Several recent epidemiological studies examined associations between exposure to per- and polyfluoroalkyl substances (PFAS) and various human health outcomes.
Richard Christian Jensen and colleagues from the University of Southern Denmark, Odense, Denmark, investigated “association between five serum PFASs and glucose-related outcomes in pregnant Danish women based on their risk of gestational diabetes mellitus (GDM).” They found that, in women with high GDM risk, the concentration of perfluorohexane sulfonic acid (PFHxS, CAS 355-46-4) “was associated with higher fasting glucose, insulin and insulin resistance,” while the concentration of perfluorononanoic acid (PFNA, CAS 375-95-1) “was associated with increased fasting insulin and beta-cell function.” However, “[i]n women with low GDM risk, no associations were found between PFAS concentrations and glucose-related outcomes.” The authors concluded that “PFHxS and PFNA concentrations were associated with impaired glycemic status in metabolically vulnerable pregnant women and might further enhance the risk of developing GDM.”
Krista Christensen and colleagues from the University of Wisconsin-Madison, Madison, U.S., evaluated data on the levels of 12 different PFASs and “metabolic syndrome components,” such as “increased waist circumference and elevated glucose,” collected within the National Health and Nutrition Examination Survey (NHANES). They found that “PFNA was associated with increased risk of metabolic syndrome” and “the highest levels of PFHxS were associated with elevated triglycerides.”
In contrast to the studies above, a “prospective nested case-control study” of PFAS and type II diabetes risk delivered “overall conflicting results” and revealed “mostly non-significant” inverse associations between exposure to individual PFASs and prospective diabetes risk. In this study, Carolina Donat-Vargas and colleagues from the Institute of Environmental Medicine, Karolinska Instituet, Stockholm, Sweden, measured plasma levels of several PFAS in a Swedish cohort at the study onset and at the 10-year follow-up examination. They then compared the values between participants with or without diabetes.
Taylor Etzel and colleagues from the Johns Hopkins Bloomberg School of Public Health, Baltimore, U.S., also used NHANES data to examine associations between PFAS and vitamin D levels. They found that “some PFAS may be associated with altered vitamin D levels in the U.S. population, and association may vary by chemical, age, and race/ethnicity.” They called for “prospective epidemiological studies” in order to confirm these findings and “determine their implications for vitamin D-associated health outcomes in children and adults.”
Also based on NHANES data, Mengmeng Huang and colleagues from the Fuli Institute of Food Science, Zhejiang University, China, reported several positive associations of individual PFASs with the risk of cardiovascular diseases (CVD), including congestive heart failure, coronary heart disease, and angina pectoris. The observed associations were “independent of traditional CVD risk factors.”
Rong Huang and colleagues from the Ministry of Education-Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, examined the association between “PFAS exposure and hypertensive disorders of pregnancy (HDP) in humans.” They found an association with preeclampsia for perfluorobutane sulfonate (PFBS, CAS 375-73-5), perfluoroundecanoic acid (PFUA, CAS 2058-94-8), and PFHxS.
Fetal and child development
Hexing Wang and colleagues from the School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education, Fudan University, Shanghai, China, found that the levels of perfluorooctanoic acid (PFOA, CAS 335-67-1) in cord serum were “negatively related to head circumference at birth” and provided evidence that “estrogens might mediate the association between exposure to PFASs and fetal growth.” Irina Gyllenhammar and colleagues from the National Food Agency, Uppsala, Sweden, reported both positive and negative associations with fetal and child growth for several PFASs, which further differed depending on the child age at follow-up. Similarly, variable “associations of PFAS concentrations in umbilical cord blood with gestational and postnatal growth” in Chinese infants were observed by Wencheng Cao and colleagues from the Hubei Provincial Center for Disease Control and Prevention, Wuhan, China.
Andreas Ernst and colleagues from the Department of Public Health, Section for Epidemiology, Aarhus University, Denmark, looked at the associations between prenatal PFAS exposure and pubertal development “in boys and girls from the Danish National Birth Cohort.” PFAS levels were measured in “maternal plasma from early gestation,” and data on puberty-related outcomes were collected in children “biannually from the age of 11 y until full maturation.” The researchers found that prenatal exposure to most PFAS was “associated with lower mean age at puberty marker onset” in both genders, however, for two PFASs “exposure was associated with higher mean age at onset of puberty in boys.” There were also several “nonmonotonic associations” observed for some combination of PFASs and puberty indicators. The authors concluded that their “study suggests sex-specific associations of altered pubertal development with prenatal exposure to PFAS.” These findings are “novel” and “replication is needed.”
Maria Averina and colleagues from the Department of Laboratory Medicine, University Hospital of North Norway, Tromso, Norway, investigated the associations between PFAS exposure and “asthma and other allergies . . . in adolescents from the Arctic region of Norway.” They found positive associations with asthma and “self-reported nickel allergy,” and no associations with “allergic rhinitis, self-reported pollen allergy, food allergy and atopic eczema.”
Jensen, R.C., et al. (2018). “Perfluoroalkyl substances and glycemic status in pregnant Danish women: The Odense Child Cohort.” Environment International 116: 101-107.
Christensen, K., et al. (2019). “Perfluoroalkyl substances and metabolic syndrome.” International Journal of Hygiene and Environmental Health 222: 147-153.
Donat-Vargas, C., et al. (2019). “Perfluoroalkyl substances and risk of type II diabetes: A prospective nested case-control study.” Environment International 123: 390-398.
Etzel, T.M., et al. (2018). “Association of serum perfluoroalkyl substance and vitamin D biomarker concentrations in NHANES, 2003-2010.” International Journal of Hygiene and Environmental Health (published November 28, 2018).
Huang, M., et al. (2018). “Serum polyfluoroalkyl chemicals are associated with risk of cardiovascular diseases in national US population.” Environment International 119: 37-46.
Huang, R., et al. (2019). “Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances and the risk of hypertensive disorders of pregnancy.” Environmental Health 18:5.
Wang, H., et al. (2019). “PFOS, PFOA, estrogen homeostasis, and birth size in Chinese infants.” Chemosphere 221: 349-355.
Gyllenhammar, I. (2018). “Perfluoroalkyl acid levels in first-time mothers in relation to offspring weight gain and growth.” Environment International 111: 191-199.
Cao, W., et al. (2018). “Perfluoroalkyl substances in umbilical cord serum and gestational and postnatal growth in a Chinese birth cohort.” Environment International 116: 197-205.
Ernst, A., et al. (2019). “Exposure to perfluoroalkyl substances during fetal life and pubertal development in boys and girls from the Danish National Birth Cohort.” Environmental Health Perspectives 127: e017004
Averina, M., et al. (2019). “Serum perfluoroalkyl substances (PFAS) and risk of asthma and various allergies in adolescents. The Tromso study Fit Futures in Northern Norway.” Environmental Research 169: 114-121.