Epidemiologic Evidence on the Health Effects of Perfluorooctanoic Acid (PFOA)

Abstract

Objective and sourcesWe reviewed the epidemiologic literature for PFOA.Data synthesisPerfluorooctanoic acid (PFOA) does not occur naturally but is present in the serum of most residents of industrialized countries (U.S. median, 4 ng/mL). Drinking water is the primary route of exposure in some populations, but exposure sources are not well understood. PFOA has been used to manufacture such products as Gore-Tex and Teflon. PFOA does not break down in the environment; the human half-life is estimated at about 3 years. PFOA is not metabolized in the body; it is not lipophilic. PFOA is not directly genotoxic; animal data indicate that it can cause several types of tumors and neonatal death and may have toxic effects on the immune, liver, and endocrine systems. Data on the human health effects of PFOA are sparse. There is relatively consistent evidence of modest positive associations with cholesterol and uric acid, although the magnitude of the cholesterol effect is inconsistent across different exposure levels. There is some but much less consistent evidence of a modest positive correlation with liver enzymes. Most findings come from cross-sectional studies, limiting conclusions. Two occupational cohort studies do not provide consistent evidence for chronic disease; both are limited by sample size and reliance on mortality data. Reproductive data have increased recently but are inconsistent, and any observed adverse effects are modest.ConclusionsEpidemiologic evidence remains limited, and to date data are insufficient to draw firm conclusions regarding the role of PFOA for any of the diseases of concern.

Associations between serum concentrations of perfluoroalkyl acids and serum lipid levels in a Chinese population

“…First, it was impossible to establish a causal inference due to the cross-sectional nature of this study (Grimes and Schulz, 2002). Second, both PFAAs and serum lipids might be jointly affected by some other attributes, substances or mechanisms that caused the associations between them (Steenland et al, 2010). Third, after the information of age, gender and BMI was adjusted, it might be still possible that residual confounding persisted due to unknown factors (Fisher et al, 2013).…”

Structure–activity relations in binding of perfluoroalkyl compounds to human thyroid hormone T3 receptor

“…For example, as one of the most concerned PFCs, PFOS is present in the blood of general population at a level of about 20 ppb and an estimated half-life of nearly 5.4 years (Calafat et al 2007;Olsen et al 2007). Because of the characteristics of wide distribution and high stability, there has been a great concern as to PFCs' potential harmful effects on human health (Steenland et al 2010).…”

Perfluorooctanoic acid binds to peroxisome proliferator-activated receptor γ and promotes adipocyte differentiation in 3T3-L1 adipocytes

“…1,7) Epidemiologic studies have shown that PFOA exposure is positively associated with increased serum cholesterol and uric acid levels. 8) Moreover, recent studies have indicated that PFOA influences the risk of obesity, as an obesogen, in mice and humans. 9,10) Obesogens are defined functionally as chemicals that promote obesity by increasing the number of fat cells or the storage of fat into existing fat cells.…”