Cord serum concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in relation to weight and size at birth.

Polyfluoroalkyl compounds (PFCs) comprise a class of man-made, fluorinated organic compounds that have been used in a variety of consumer and industrial applications. Although these have been produced for many years, only recently have reports surfaced suggesting widespread exposure in wildlife and humans (Butenhoff et al. 2006; Calafat et al. 2007; Giesy and Kannan 2001; Houde et al. 2006; Kannan et al. 2004). Two of the most widely detected and studied compounds in this class are perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA). PFOS and related compounds (polyfluorinated sulfonamides) are surfactants used in applications ranging from oil and water repellents for fabrics, apparel, carpets, and paper coatings to specialty chemical applications such as insecticides and fire fighting foams (3M Company 1999). PFOA and its salts are used as chemical intermediates and processing aids in the production of fluoropolymers and fluoroelastomers. Both PFOS and PFOA have shown the potential for developmental toxicity in animal studies. PFOS has been shown, in rats and mice, to induce developmental and reproductive effects, such as reduced birth weight, decreased gestational length, structural defects, developmental delays, and increased neonatal mortality (Fuentes et al. 2006; Grasty et al. 2003; Lau et al. 2003; Luebker et al. 2005a, 2005b; Thibodeaux et al. 2003). Recent studies have also reported developmental toxicity from PFOA in rodents, including pregnancy loss, reduced fetal weight, reduced postnatal survival, and delays in postnatal growth and development in offspring (Butenhoff et al. 2004; Lau et al. 2004, 2006). However, such studies of PFOS and PFOA have been conducted using doses that produce serum concentrations much higher than general population human exposures. There are limited epidemiologic data on the potential impacts of PFC exposure on fetal growth and development. However, one recent occupational study found no association between employment in jobs with high exposure to PFOS before the end of pregnancy and maternally reported birth weight (Grice et al. 2007). PFOS and PFOA have also been shown to cause reductions in serum cholesterol and/or triglycerides in several animal species (Haughom and Spydevold 1992; Seacat et al. 2002, 2003; Thibodeaux et al. 2003). Conversely, a few cross-sectional occupational studies conducted among fluorochemical production employees have reported positive relationships between PFOS and/or PFOA concentrations and serum lipid levels (Gilliland and Mandel 1996; Olsen et al. 1999, 2003). The fetus is likely to be sensitive to the availability of cholesterol and triglycerides, which support cellular growth, differentiation, and adipose accumulation (Woollett 2001). Disruptions to normal fetal growth and development have been associated with effects across the lifespan, including adverse neonatal and childhood outcomes (Hofman et al. 1997; Kramer et al. 1990) and metabolic diseases in adulthood (Barker 2006). In a previous report, we documented factors associated with cord serum concentrations of PFOS and PFOA in a population of newborn deliveries known as the Baltimore THREE study (Apelberg et al. 2007). In this study, we examined the relationship between these concentrations and gestational age, birth weight, and measures of birth size, including head circumference, length, and ponderal index (a measure of body mass at birth).