Dioxin-like activity in the blood of Greenlandic Inuit and Danish women: a pilot study

Abstract

Objectives.(1) To determine whether plasma dioxin-like (DL) bioactivity differs between Inuit living in different Greenlandic districts, (2) to compare the DL activity of the Inuit having high burdens of POPs with a low-burden study group (Danish volunteers), and (3) to evaluate DL activity associations to POP exposure biomarkers and/or lifestyle factors. Study design. The study was a cross-sectional survey, including randomized inhabitants (70) from 6 different Greenlandic districts and young Danish volunteers (22). Methods. POPs and fatty acids profiles were analysed. Aryl hydrocarbon receptor (AhR) mediated DL-activity was determined by exposure of Hepa1.12cR AhR-CALUX reporter cell line to hexane: ethanol plasma extracts. Results. The sum PCBs/POPs level of Inuit was more than10 times higher than the levels found in Danish volunteers, and for both study groups the level was positively associated with age. The TCDD equivalent of the determined DL-activity, AhR-TEQ, differed between the Greenlandic districts. The AhR-TEQ data of the combined Inuit was significantly higher compared with the Danish women. AhR-TEQ of Inuit were positively associated with plasma POPs after adjustment for age and/or the ratio of n-3 to n-6 fatty acids, whereas no correlations were found for the Danish samples. Conclusions. AhR-TEQ differs between Inuit and Danish plasma samples. Plasma POP levels alone cannot be used as a biomarker for DL-activity. We suggest that the profile and level of plasma POPs, geographical location and diet have the greatest impact on plasma dioxin activity. Further studies are needed to elucidate the differences in geographical determinants of blood DL-activity.

Level and temporal trend of perfluoroalkyl acids in Greenlandic Inuit

“…1). Participants from Nuuk during 2000Á2002 were randomly selected from a cross-sectional study assessing legacy POP exposure on osteoporosis-related ultrasound bone measurements in Greenlandic Inuit women (29), and the rest of the participants were randomly selected from projects in the human health program of the ongoing circumpolar AMAP (21,30,31). The participation rate was more than 80% (21,29Á31).…”

Health effects associated with measured levels of contaminants in the Arctic

“…Moreover, levels were positively associated with age in both study groups. The AhR-TEQ level was significantly higher in Inuit and was positively associated with plasma POPs, whereas no correlations were found for the Danish samples (94,103). Comparisons between European and Greenlandic male serum POP levels showed significantly higher levels in Inuit, and as a result lower ER and AhR transactivity and a tendency towards higher AR activity for the Greenlandic serum samples.…”

“…However, for men in Nuuk and Sisimiut, a tendency towards increased serum POP-induced AR activity was observed (Fig. 4.2) (93,94). …”

“…In Greenland, regional differences and sex differences (highest in men) are observed in serum POP levels. The highest levels are found in Inuit living on the east coast (Ittoqqortoormiit and Tasiilaq) and in the north-west (Qaanaaq) (92–94). …”

“…The lowest medians of the tetrachlorodibenzo-p-dioxin (AhR-TCDD) and toxic equivalence (AhR-TEQ) values were observed in Ittoqqortoormiit (East) and Qaanaaq (North-west), with higher AhR-TEQ levels for both sexes observed in Tasiilaq (only five individuals), Narsaq, Sisimiut and Nuuk, and the highest in Disko Bay (Qeqertarsuaq) (Fig. 4.2) (93,94). A tendency towards an inverse relation between the dioxin-like-induced AhR and ER activity supports the perception that dioxins exert an antiestrogenic effect.…”