Environ. Sci. Technol. 2010, 44, 5225–5232
Dietary Patterns and Plasma Concentrations of Perfluorinated Compounds in 315 Norwegian Women: The NOWAC Postgenome Study C H A R L O T T A R Y L A N D E R , * ,†,‡ T O R K J E L M . S A N D A N G E R , †,‡ LIVAR FRØYLAND,§ AND EILIV LUND† Department of Community Medicine, University of Tromsø, 9037 Tromsø, Norway, Norwegian Institute for Air Research, The Polar Environmental Centre, 9296 Tromsø, Norway, and National Institute for Nutrition and Seafood Research (NIFES), 5817 Bergen, Norway
Received January 21, 2010. Revised manuscript received May 12, 2010. Accepted May 26, 2010.
This study was undertaken to assess the impact of selfreported dietary habits and lifestyle on the plasma concentration of selected perfluorinated compounds (PFCs) in a representative group of 315 middle-aged Norwegian women (48-62 years of age). Perfluorooctane sulfonate (PFOS; median: 20 ng/mL), perfluorooctanoate (PFOA; 4.4 ng/mL), perfluorohexane sulfonate (PFHxS; 1.0 ng/mL), and perfluorononanoate (PFNA; 0.81 ng/ mL) were detected in more than 90% of the plasma samples. By using multivariate data analysis, women who ate fish or “fish eaters” (high consumers of fish and shellfish) were identified as having increased plasma concentrations of PFOS, PFNA, and PFHxS. Younger women with a larger household and a “western” diet consisting of rice, pasta, water, white and red meat, chocolate, snacks, and pastries had lower concentrations of the same compounds. No specific food cluster was associated with increased PFOA concentrations, indicating that the dietary impact on PFOA concentrations was different from that of the other investigated PFCs. This study confirms that the total diet is a major contributor to human body burdens of selected PFCs, but the identification of dietary predictors is highly dependent on the dietary habits within the population studied due to the ubiquitous presence of PFCs in many kinds of food.
Introduction The production of fluoropolymers started as early as 1949 although the production volumes before 1970 were estimated to be low (1).Concentrations of perfluorinated compounds (PFCs) were reported in human blood samples from workers in fluoropolymer industries in the late 1990s by Olsen and Gilliland et al. (2, 3) even though elemental fluoride had been detected already in the late 1960s in human serum. Over the past decade numerous articles have been published on PFCs * Corresponding author e-mail:
[email protected]; phone: +4741643404. † University of Tromsø. ‡ Norwegian Institute for Air Research, The Polar Environmental Centre. § National Institute for Nutrition and Seafood Research. 10.1021/es100224q
2010 American Chemical Society
Published on Web 06/07/2010
in various environments and in human blood taken from people around the world, so there is little doubt that PFCs are widespread pollutants. Perfluorooctane sulfonate (PFOS) is the major PFC in human blood samples but perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorononanoate (PFNA) are also frequently detected in various concentrations. PFCs have unique chemical properties (repelling both water and fat) and have therefore been widely used as surfactants and surface treatment products in industry and in consumer products. In Norway, PFOS has mainly been used in fire fighting foam on oil rigs although there is limited information available about the use of the other PFCs (4). Concerns were raised since several PFCs were found to bioaccumulate and magnify in the food chain (5). Toxicological findings showed that PFOS and PFOA act as peroxisome proliferators and interfere with fatty acid metabolism in rodents (6). Yet, no association was found for place of work (as an exposure marker), bladder cancer, mortality, and self-reported health in workers from fluorochemical industries (7–9). However, PFOA exposure was associated with increased mortality of prostate cancer, cerebrovascular disease, and diabetes among occupationally exposed workers, although the results were inconclusive (10). Some of the PFCs have also been associated with indicators of metabolic syndrome in a general population (11). After more than 40 years of production, 3M, the major producer of PFOS voluntarily withdrew it from production in 2000 (12). Other producers followed, and the phasing out of PFOA and PFOA precursors has begun (13). Higher concentrations of PFCs have been reported from some industrial countries than from parts of the developing world, indicating that PFCs are lifestyle-related pollutants (14). The exposure scenario for humans is, however, complex since PFCs have been detected in many kinds of food (15), household dust (16), a number of consumer products (17), and drinking water (18). The diet has recently been considered the major pathway (19) and animal products seem to contribute to a larger extent than vegetarian foodstuffs (20, 15). There are only a limited number of studies that investigate the relationship between self-reported dietary intake and plasma concentrations of PFCs, and the findings are contradictory (21, 22). Intake of fish has been identified as a possible source (22), but also red meat, snacks, and animal fat were associated with increased plasma concentrations of some PFCs (21). So far, the focus has mainly been on specific foodstuffs, while dietary patterns (food clusters) have not been evaluated. This study was undertaken to assess the impact of a large number of self-reported dietary and lifestyle related variables on plasma concentrations of PFCs in the general population using food clusters. Plasma concentrations of marine-derived omega 3 fatty acids were also assessed as a biomarker for fatty fish intake as previous investigating has identified fish as a potential source.
Materials and Methods Study Population and Collection of Blood Samples. The women taking part in the current study were all participants of the national representative Norwegian Women And Cancer Study (NOWAC), which consists of more than 170 000 Norwegian women aged 30-70 years (23). The participating women were randomly chosen from the central person registry in Norway and invited to participate in the survey through an invitational letter sent to their home address. The external validity of NOWAC has been thoroughly validated (24). All participants answered a detailed questionVOL. 44, NO. 13, 2010 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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TABLE 1. Plasma Concentration of PFCs (ng/mL) and Omega-3 Fatty Acids (mg/mL) in the Study Group (N = 326)a PFC concentration (ng/mL)
total N ) 326 median
AM
GM (95% CI)
range
LOD
% > LOD
PFOS PFOS branched PFOS linear PFHxS PFOA PFNA PFHpS PFOSA PFHpA % linear PFOS
20 6.1 14 1.0 4.4 0.81 0.32 0.02 N/A 70
22 6.6 15 1.4 5.1 0.87 0.34 0.059 N/A 69
20 (19-21) 6 (5.6-6.3) 14 (13-14) 1.1 (0.91-1.2) 4.6 (4.3-4.9) 0.76 (0.72-0.80) N/A N/A N/A 69
5.4-84 0.70-25 4.2-60 0.04-13 0.79-21
