An Exploratory Study of Diabetes in a First Nation Community with Respect to Serum Concentrations of p,p’-DDE and PCBs and Fish Consumption

This study examined the association between self-reported diabetes, fish consumption and serum levels of organochlorines in a First Nation community. One quarter of the 101 participants reported diabetes. Serum PCBs, but not p,p’-DDE, were positively correlated to consumption frequency of total fish, walleye and pike, but not trout. Reported diabetes was positively associated to p,p’-DDE and some PCB congeners. Odds Ratios (OR) for reported diabetes for those in the upper 75th percentile for serum p,p’-DDE compared to the others were 3.5 (95% CI 1–13.8) and 6.1 (95% CI 1.4–27.3) (weight wet and lipid-standardized values, respectively) and for total sum of PCBs: 4.91 (95% CI 1.4–19.0) and 5.51 (95% CI 1.3–24.1). For participants who were in the upper 50th percentile for trout and white fish intake, reported diabetes was respectively 6 and 4 times lower compared to the others. These findings support the hypothesis that environmental exposure to elevated p,p’-DDE and PCBs is associated with increased risk of diabetes. Consumption of trout and white fish may be beneficial to reduce risk

No evidence of selenosis from a selenium-rich diet in the Brazilian Amazon

Selenium (Se) is an essential element and a well-known anti-oxidant. In the Lower Tapajos River region of the Brazilian Amazon, biomarkers of Se range from normal to very high. The local traditional diet includes important Se sources such as Brazil nuts, chicken, game meat and certain fish species. Some studies have reported alterations in keratin structure, gastrointestinal problems and paresthesia in populations with high Se intake. The objective of the present study was to evaluate cutaneous and garlic odor of the breath signs and sentinel symptoms of Se toxicity (selenosis) in relation to Se status in communities along the Tapajos River. Participants (N = 448), aged 15-87 years, were recruited from 12 communities. Se concentrations were measured in blood (B-Se) and plasma (P-Se) by ICP-MS. A nurse performed an examination of the hair, nails, skin and breath for signs of Se toxicity. Interview-administered questionnaires were used to collect information on socio-demographics, medical history and possible symptoms of Se toxicity. In this population, the median levels of B-Se and P-Se were 228.4 mu g/L (range 103.3-1500.2 mu g/L) and 134.8 mu g/L (range 53.6-913.2 mu g/L) respectively. Although B-Se and P-Se surpassed concentrations considered toxic (B-Se: 1000 mu g/L (U.S. EPA, 2002)), no dermal or breath signs or symptoms of Se toxicity were associated with the biomarkers of Se status. In the present study population, where Se intake is mostly from traditional diet, there is no evidence of selenosis. These findings support the need to re-assess Se toxicity considering factors such as the chemical form of Se exposure, route of exposure (inhaled versus ingested), co-exposures to toxic elements such as mercury. Considering the current food transition towards a western diet in the Amazon, further studies should address the possible association between high Se status and cardiometabolic health in this study population. (C) 2011 Elsevier Ltd. All rights reserved.Canadian Institutes of Health ResearchFundacao de Amparo a Pesquisa do Estado de Sao PauloCanadian Natural Sciences and Engineering CouncilInternational Development Research Centr

Selenium and Mercury in the Brazilian Amazon: Opposing Influences on Age-Related Cataracts

BACKGROUND: Age-related cataracts (ARCs) are an important cause of blindness in developing countries. Although antioxidants may be part of the body's defense to prevent ARC, environmental contaminants may contribute to cataractogenesis. In fish-eating populations of the lower Tapajos region, elevated exposure to mercury (Hg) has been reported, and blood levels of selenium (Se) range from normal to very high (> 1,000 mu g/L). OBJECTIVES: We examined ARCs in relation to these elements among adults (>= 40 years of age) from 12 riverside communities. METHODS: Participants (n = 211) provided blood samples and underwent an extensive ocular examination. Inductively coupled plasma mass spectrometry was used to assess Hg and Se in blood and plasma. RESULTS: One-third (n = 69; 32.7%) of the participants had ARC. Lower plasma Se (P-Se; < 25th percentile, 110 mu g/L) and higher blood Hg (B-Hg; >= 25th percentile, 25 mu g/L) were associated with a higher prevalence odds ratio (POR) of ARC [adjusted POR (95% confidence interval), 2.69 (1.11-6.56) and 4.45 (1.43-13.83), respectively]. Among participants with high P-Se, we observed a positive but nonsignificant association with high B-Hg exposure, whereas among those with low B-Hg, we observed no association for P-Se. However, compared with the optimum situation (high P-Se, low B-Hg), the POR for those with low P-Se and high B-Hg was 16.4 (3.0-87.9). This finding suggests a synergistic effect. CONCLUSION: Our results suggest that persons in this population with elevated Hg, the cataractogenic effects of Hg may be offset by Se. Because of the relatively small sample size and possible confounding by other dietary nutrients, additional studies with sufficient power to assess multiple nutrient and toxic interactions are required to confirm these findings.Canadian Institutes of Health Research (CIHR)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Canadian Natural Sciences and Engineering Council (NSERC)International Development Research Centre (IDRC) - Canad

Fish intake and serum fatty acid profiles from freshwater fish

Fish intake and serum fatty acid profiles from freshwater fish1,2,3 Aline Philibert, Claire Vanier, Nadia Abdelouahab, Hing Man Chan and Donna Mergler 1 From CINBIOSE, Universit\ue9 du Qu\ue9bec \ue0 Montr\ue9al, Montr\ue9al, Canada (AP, CV, NA, and DM), and the UNBC Community Health Program, Prince George, Canada (HMC) Background: Although high mercury concentrations in fish diets raise an alarm, fish can also be a healthy choice because it is the primary source of n\u963 fatty acids (FAs). However, little information is available on the contribution of freshwater fish to serum FA concentrations. Objective: This study examined the FA pathway from fish to serum in 243 moderate consumers of freshwater fish. Design: A food-frequency questionnaire was used to determine the intakes of freshwater fish caught locally and not sold in markets and of fish purchased in markets ( \ub1 SD: 58 \ub1 63 g/d). Locally caught freshwater fish accounted for an average of 45% of total fish intake. Fish were categorized as lean or fatty on the basis of the eicosapentaenoic acid + docosahexaenoic acid content estimated from published data. Serum FA concentrations were determined by gas chromatography. Results: The results showed no relation between total fish intake or estimated n\u963 FA intake from all fish and serum n\u963 FA concentrations. Only fatty fish intake, particularly salmonid, and estimated EPA + DHA intake from fatty fish were significantly associated with serum EPA + DHA (R2 =3D 0.41 and 0.40, respectively). No relation was observed between the quantity of locally caught fish (g/d) consumed or the estimated FA intake from locally caught fish and serum n\u963 FAs. Age, sex, and lipid metabolism medication were associated with serum n\u963 FA concentrations. Neither blood selenium nor blood mercury was associated with serum FAs. Conclusion: The relation between fatty fish consumption and serum n\u963 FAs cannot be generalized to all fish intakes. Key Words: Fatty acids \u95 n\u963 fatty acids \u95 n\u966 fatty acids \u95 EPA \u95 DHA \u95 serum fatty acids \u95 fish consumption \u95 food-frequency questionnaire \u95 freshwater fish \u95 fatty fis

Phosphorus limitation of bacterial growth in high Arctic lakes and ponds

Water from lakes and tundra ponds on Banks, Melville, Ellef-Ringnes, Ellesmere and Devon Island (74–79°N, 82–116°W) in the Canadian high Arctic was studied in batch culture experiments to test whether nitrogen, phosphorus or organic carbon limited bacterial growth and biomass accumulation. Water samples containing indigenous bacteria were amended with carbon (glucose), nitrogen (nitrate) or phosphorus (phosphate), either alone or in combination, and were incubated in the dark at ambient temperatures. Bacterial growth was measured as the rate of protein synthesis and the accumulation of bacterial cells. Bacterial growth was significantly enhanced in all cultures amended with phosphorus. There was no indication of primary carbon or nitrogen limitation in either lakes or ponds, but the combined addition of phosphorus and either carbon, nitrogen or both, had a positive effect on bacterial growth in the lakes but not in ponds. This contrasting response in Arctic lakes and ponds can be predicted from in situ concentrations of dissolved nutrients: total dissolved phosphorus was low in all systems (= 10 μg L−1), whereas total dissolved nitrogen and organic carbon was on average 24 and 7 times higher in ponds. Pelagic bacteria in lakes and ponds of the high Arctic seem to follow the general pattern of phosphorus limitation previously observed in many temperate and tropical freshwater systems.Wilhelm Granéli, Stefan Bertilsson, Aline Philiber

Effects of late Holocene wildfires on diatom assemblages in Christina Lake, Alberta, Canada

Philibert, Aline; Prairie, Yves T; Campbell, Ian; Laird, Lan