Determinants of per- and polyfluoroalkyl substances (PFAS) in midlife women: Evidence of racial/ethnic and geographic differences in PFAS exposure.

BACKGROUND: Per- and poly-fluoroalkyl substances (PFAS) are public health concerns because of widespread exposure through contaminated foods/drinking water. Although some determinants of PFAS exposure have been suggested, the role of geographic location and race/ethnicity in PFAS exposure has not been well characterized.
OBJECTIVES: We examined potential determinants of PFAS from the Study of Women's Health Across the Nation (SWAN).
METHODS: This study includes 1302 women aged 45-56 years from 5 SWAN sites where white women and women from one minority group were recruited (black from Southeast Michigan, Pittsburgh, Boston; Chinese from Oakland; Japanese from Los Angeles). We determined concentrations of 11 PFAS in serum samples collected in 1999-2000 and examined 7 PFAS detected in most women (>97%). Linear regression with backward elimination was used to identify important determinants of PFAS serum concentrations among a set of pre-specified variables (age, body mass index, site, race/ethnicity, education, financial hardship, occupation, born outside the United States (US), parity, menstrual bleeding within the past year, smoking status, alcohol consumption, and consumption of fish, dairy, pizza, salty snack, and French fries).
RESULTS: Site and race/ethnicity were two major determinants of PFAS. White women had higher concentrations of linear perfluorooctanoic acid (PFOA) compared with the Chinese in Oakland (p < 0.0001) and blacks in Pittsburgh (p = 0.048). Black women in Southeast Michigan and Boston (vs. white women) had higher concentrations of linear (p < 0.001 for Southeast Michigan; p < 0.0001 for Boston) and total perfluorooctane sulfonic acid (PFOS) (p < 0.001 for both Southeast Michigan and Boston) and 2-(N-methyl-perfluorooctane sulfonamido) acetic acid (p = 0.02 for Southeast Michigan; p < 0.001 for Boston). Chinese (Oakland) and Japanese (Los Angeles) women had higher concentrations of perfluorononanoic acid (PFNA) compared with white women in each site (p < 0.01 for both). Within white women, those in Pittsburgh had relatively higher concentrations of PFAS. Within Chinese and Japanese women, those who were born outside the US had significantly lower concentrations of most PFAS but significantly higher PFNA concentrations. Menstrual bleeding and parity were significantly associated with lower PFAS concentrations. Higher intake of salty snacks including popcorn was significantly associated with higher concentrations of linear PFOA, PFOS and 2-(N-ethyl-perfluorooctane sulfonamido) acetic acid. DISCUSSION: Geographic locations and race/ethnicity play an important role in differential exposure to PFAS, with racial/ethnic burdens differing between PFOS, PFOA and PFNA. Menstruation and parity were also determinants of PFAS concentrations possibly as an elimination route.