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There is growing evidence that cardiovascular health can be affected by exposure to methylmercury (MeHg), by a mechanism involving oxidative stress. Paraoxonase 1 (PON1) is a high-density lipoprotein-bound enzyme that hydrolyzes toxic oxidized lipids and protects against cardiovascular diseases. Evidence from in vitro studies indicates that MeHg can inhibit PON1 activity but little is known regarding this effect in humans. We investigated whether increased blood mercury levels are associated with decreased serum PON1 activity in Cree people who are exposed to MeHg by fish consumption. We conducted a multi-community study of 881 Cree adults living in Eastern James Bay communities (Canada). Multivariate analyses considered sociodemographic, anthropometric, clinical, dietary and lifestyle variables and six PON1 gene variants (rs705379 (−108C/T), rs662 (Q192R), rs854560 (L55M), rs854572 (−909C/G), rs854571 (−832C/T) and rs705381 (−162C/T)). In a multiple regression model adjusted for all potential confounding factors and the rs854560 PON1 variant, a statistically significant MeHg*rs705379 interaction was observed. Blood mercury levels were inversely associated with serum PON1 activities in individual homozygous for the −108T allele (P=0.009). Our results suggest a gene-environment interaction between the rs705379 polymorphism and MeHg exposure on PON1 activity levels in this aboriginal population. This finding will need to be replicated in other population studies. [ABSTRACT FROM AUTHOR]

Prenatal exposures to legacy persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and dioxin-like compounds (DLC), as well as polybrominated diphenyl ethers (PBDE), were analyzed in pregnant women from 10 Caribbean countries. A total of 438 samples were collected and descriptive statistics calculated and compared to comparable Canadian Health Measure Survey (CHMS) and U.S. National Health and Nutritional Examination Survey (NHANES) datasets. Maternal POPs blood concentrations were found to be generally relatively low in the Caribbean samples compared with the U.S. and Canada datasets. Evidence of exposure to DLC and PBDE was established. DLC levels ranged from a geometric mean low of 3.96 pg/g lipids in Antigua and Barbuda to a high of 11.4 pg/g lipids in St. Lucia. Several of the PBDEs (15, 17, 25, 28, 33, 100) were detected in less than 60% of the country׳s samples. For PBDE-47, significantly higher levels were found in Bermuda, while Jamaica recorded a significantly low level. The overall calculated concentration of PBDE-47 for the Caribbean (5.33 μg/kg lipids) was significantly lower than the concentrations measured for the U.S. (10.83 μg/kg lipids) and Canada (23.90 μg/kg lipids). This study confirms that prenatal expose to multiple environmental chemicals is taking place in the Caribbean and highlights the need to implement surveillance programs that continuously monitor, intervene, and evaluate the levels of these toxic environmental contaminants to ensure that they are reduced as much as possible and that the health risk to humans, in particular the unborn child, are minimized. [ABSTRACT FROM AUTHOR]

Background Household crowding is an important problem in some aboriginal communities that is reaching particularly high levels among the circumpolar Inuit. Living in overcrowded conditions may endanger health via stress pathophysiology. This study examines whether higher household crowding is associated with stressrelated physiological dysregulations among the Inuit. Methods Cross-sectional data on 822 Inuit adults were taken from the 2004 Qanuippitaa? How are we? Nunavik Inuit Health Survey. Chronic stress was measured using the concept of allostatic load (AL) representing the multisystemic biological 'wear and tear' of chronic stress. A summary index of AL was constructed using 14 physiological indicators compiled into a traditional count-based index and a binary variable that contrasted people at risk on at least seven physiological indicators. Household crowding was measured using indicators of household size (total number of people and number of children per house) and overcrowding defined as more than one person per room. Data were analysed using weighted Generalised Estimating Equations controlling for participants' age, sex, income, diet and involvement in traditional activities. Results Higher household crowding was significantly associated with elevated AL levels and with greater odds of being at risk on at least seven physiological indicators, especially among women and independently of individuals' characteristics. Conclusions This study demonstrates that household crowding is a source of chronic stress among the Inuit of Nunavik. Differential housing conditions are shown to be a marker of health inequalities among this population. Housing conditions are a critical public health issue in many aboriginal communities that must be investigated further to inform healthy and sustainable housing strategies. [ABSTRACT FROM AUTHOR]

Abstract: Pyrethroid pesticides are commonly used in tropical regions such as the Caribbean as household insecticides, pet sprays, and where malaria is endemic, impregnated into mosquito-repellent nets. Of particular concern is exposure during pregnancy, as these compounds have the potential to cross the placental barrier and interfere with fetal development, as was shown in limited animal studies. The objective of this study was to evaluate exposure to pyrethroids to pregnant women residing in 10 English-speaking Caribbean countries. Pyrethroid exposures were determined by analyzing five pyrethroid metabolites in urine samples from 295 pregnant women: cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA, and 4-F-3-PBA. Pyrethroid metabolite concentrations in Caribbean pregnant women were generally higher in the 10 Caribbean countries than levels reported for Canadian and U.S. women. In Antigua & Barbuda and Jamaica participants the geometric mean concentrations of cis-DBCA was significantly higher than in the other nine countries together (p <0.0001 and <0.0012 respectively). For cis- and trans-DCCA, only Antigua & Barbuda women differed significantly from participants of the other nine Caribbean countries (p <0.0001). Urinary 4-F-3-PBA and 3-PBA levels were significantly higher in Antigua & Barbuda (p <0.0028 and p <0.0001 respectively) as well as in Grenada (p <0.0001 and p <0.007 respectively). These results indicate extensive use of pyrethroid compounds such as permethrin and cypermethrin in Caribbean households. In Antigua & Barbuda, the data reveals a greater use of deltamethrin. This study underscores the need for Caribbean public health authorities to encourage their populations, and in particular pregnant women, to utilize this class of pesticides more judiciously given the potentially adverse effects of exposure on fetuses and infants. [Copyright &y& Elsevier]

Objective: To evaluate subclinical atherosclerosis in Nunavik Inuit and its correlation to traditional cardiovascular disease risk factor. Method: The intima–media thickness (IMT) of 12 segments of the carotid arteries (IMT12_seg) free of plaque were assessed in randomly selected 40 years old and older Inuit from. Clinical assessment was performed which included fasting plasma glucose, fasting insulin, systemic blood pressure, body mass index, smoking, circulating blood lipids and oral glucose tolerance test. In addition, documented presence of ischemic heart disease (IHD), stroke, diabetes mellitus, hypertension and dyslipidemia were determined from medical files. Results: The average age of the 287 participants was 51.2±0.6 years (56.8% women). Mean IMT12_seg was 0.80±0.17mm (range: 0.55–1.47mm). Compared with disease free Inuit, individuals with history of stroke showed greater carotid internal IMT (0.68±0.01mm vs. 0.96±0.15mm respectively; p <0.005) but no difference was observed for IHD. Hypertensive and dyslipidemic Inuit had higher IMT12_seg compared to risk factor free individuals but no difference was observed in diabetics. None of the clinical assessments were associated with IMT12_seg. In a multivariate backward elimination model, only age, gender, and medically documented history of hypertension were found to be predictors of IMT12_seg (adjusted r-square of 0.54; p <0.0001). Conclusion: Compared with disease free Nunavik Inuit, subclinical signs of atherosclerosis determined by IMT was higher in individual diagnosed with stroke. Independent predictors of IMT12_seg in our group were age, gender and history of hypertension. No other traditional risk factors imparted IMT. [ABSTRACT FROM AUTHOR]

Background: The beneficial effects of prenatal and early postnatal intakes of omega-3 (n-3) polyunsaturated fatty acids (PUFAs) on cognitive development during infancy are well recognized. However, few studies have examined the extent to which these benefits continue to be evident in childhood. Objective: The aim of this study was to examine the relation of n-3 PUFAs and seafood-contaminant intake with memory function in school-age children from a fish-eating community. Design: In a prospective, longitudinal study in Arctic Quebec, we assessed Inuit children (n = 154; mean age: 11.3 y) by using a continuous visual recognition task to measure 2 event-related potential components related to recognition memory processing: the FN400 and the late positive component (LPC). Children were also examined by using 2 well-established neurobehavioral assessments of memory: the Digit span forward from Wechsler Intelligence Scales for Children, 4th edition, and the California Verbal Learning Test-Children's Version. Results: Repeated-measures analyses of variance revealed that children with higher cord plasma concentrations of docosahexaenoic acid (DHA), which is an important n-3 PUFA, had a shorter FN400 latency and a larger LPC amplitude; and higher plasma DHA concentrations at the time of testing were associated with increased FN400 amplitude. Cord DHA-related effects were observed regardless of seafood-contaminant amounts. Multiple regression analyses also showed positive associations between cord DHA concentrations and performance on neurobehavioral assessments of memory. Conclusion: To our knowledge, this study provides the first neurophysiologic and neurobehavioral evidence of long-term beneficial effects of n-3 PUFA intake in utero on memory function in school-age children. [ABSTRACT FROM AUTHOR]

The article discusses a study which aimed to determine whether higher dairy product intake will have beneficial effects on body weight and cardiovascular disease (CVD) risk factors among a population in dietary transition, the Nunavik Inuit in Canada. The researchers found no substantial relationship and concluded that the daily consumption of dairy products is probably not adequate, as experienced in North American populations.

Epidemiological studies report inverse associations between blood vitamin D, as measured by 25-hydroxyvitamin D [25(OH)D] concentrations, and insulin resistance (IR) among predominantly overweight individuals. In a cross-sectional survey of 5 Cree communities in Quebec, Canada, we determined if 25(OH)D is associated with IR and β-cell function in a largely obese, ethnic minority at high risk of developing type 2 diabetes. A total of 510 participants (=18 y) without type 1 or type 2 diabetes, assessed for serum 25(OH)D, fasting plasma glucose and insulin, and anthropometric and lifestyle variables, were included in the analyses. Multivariable linear regressions adjusted for covariates were performed for homeostasis model assessment of IR (HOMA-IR) and β-cell function (HOMA-B) in relation to serum 25(OH)D. Serum 25(OH)D (per 10 nmol/L increment) was inversely associated with HOMA-IR (β = -0.005; SE = 0.002; P = 0.004) and HOMA-B (β = -0.004; SE = 0.002; P = 0.006) in models adjusted for age, sex, physical activity, education, alcohol consumption, and smoking. When further adjusted for BMI, associations were no longer significant for either HOMA-IR (β = 0.001, SE = 0.002, P = 0.572) or HOMA-B (β = 0.001, SE = 0.001, P = 0.498). The modest inverse associations between 25(OH)D and IR reported previously were not observed in this population after adjusting for adiposity. Future longitudinal studies investigating the interrelationship among 25(OH)D, adiposity, and the risk of developing metabolic syndrome and type 2 diabetes are warranted. [ABSTRACT FROM AUTHOR]

Objectives. Because of their recent adoption of a Westernized lifestyle, an increased risk of developing hypertension (HTN) is suspected among Inuit populations. This study aimed to assess the exact prevalence of HTN in Nunavik Inuit and to examine its association with other major risk factors of cardiovascular disease. Study design. A cross-sectional population-based study. Methods. We analysed biological and anthropometric data and the medical history of 832 Inuit. Results. The overall prevalence of HTN (⩾140/90 mmHg or the use of medication) was 19% with no gender difference. Obesity (body mass index [BMI] ⩾30 kg/m2) was the highest prevalent cardiovascular risk factor (23%), and was significantly associated with HTN (OR for BMI<25 kg/m2 vs. BMI 30-34 kg/m2: 7.9 [3.5-17.9]; OR for BMI<25 kg/m2 vs. BMI ⩾35 kg/m2: 14.4 [5.6-36.7]). An increase in odds of prehypertension (preHTN) (130-139/80-89 mmHg) was also observed as the BMI increased (p for trend, p<0.0001). Conclusion. The prevalence of HTN in the Inuit populations has reached values similar to those of their Westernized counterparts. Furthermore, not only HTN but also preHTN states are significantly associated with obesity even after adjusting for confounding variables. These results clearly indicate that HTN is becoming a growing health challenge in Nunavik because of pandemic obesity. [ABSTRACT FROM AUTHOR]

Epidemiological evidence suggests a negative impact of methylmercury on the cardiovascular system, but findings regarding the effect on blood pressure (BP) are not consistent. We aimed to study the impact of mercury levels on BP among Nunavik Inuit adults. The health survey Qanuippitaa? was conducted in Nunavik (northern Quebec, Canada), and data were obtained from 732 Inuit > or = 18 years of age. Anthropometric blood samples, as well as systolic BP and diastolic BP, were assessed. Pulse pressure (systolic BP-diastolic BP) was calculated. Mercury blood concentration was used as a biomarker of recent exposure. Simple relations between mercury and BP parameters were studied by using the Pearson correlation, whereas multiple regressions were performed to control for confounders. Mean age of the participants was 34.3 years (95% CI: 33.6 to 34.9 years). Systolic BP, diastolic BP, and pulse pressure means were 117 mm Hg (95% CI: 116 to 118 mm Hg), 73 mm Hg (95% CI: 72 to 74 mm Hg), and 43 mm Hg (95% CI: 42 to 44 mm Hg), respectively. Mercury mean was 50.2 nmol/L. In multivariable analyses, mercury was associated with systolic BP (beta=2.14; P=0.0004), whereas the association with diastolic BP was near the significance level (beta=0.96; P=0.069). In conclusion, mercury is associated with increasing BP and pulse pressure among Nunavik Inuit adults after considering the effect of fish nutrients (n-3 fatty acids and selenium) and other confounders. [ABSTRACT FROM AUTHOR]

French Polynesians consume high quantities of fish and are therefore exposed to seafood-related contaminants such as mercury (Hg) or lead (Pb) and nutrients such as iodine, selenium and long chain polyunsaturated fatty acids (LC-PUFAs). As the developing foetus is sensitive to contaminants and nutrients, a cross-sectional study was conducted in French Polynesia in 2005-2006 to assess prenatal exposure to contaminants and nutrients through fish consumption. Two hundred and forty one (241) delivering women originating from all islands of French Polynesia were recruited and agreed to answer questions on fish consumption and gave permission to collect umbilical cord blood for metals and nutrients analyses. All parameters were found in high concentrations in cord blood samples except for lead. Mercury concentrations averaged 64.6 nmol/L (or 13 µg/L) with values ranging from 0.25 to 240 nmol/L. Of the sample, 82.5% had Hg concentrations above the US-EPA blood guideline of 5.8 µg/L. Tuna was the fish species which contributed the most to Hg exposure. High selenium and LCPUFAs may counterbalance the potential risk of prenatal exposure to Hg in French Polynesia. Due to the high fish consumption of mothers, Polynesian newborns are prenatally exposed to high doses of mercury. Although selenium and omega--3 fatty acids may counteract mercury toxicity, informing pregnant women on both the mercury and nutrient content of local fish species is important. [ABSTRACT FROM AUTHOR]

French Polynesians, like other remote maritime populations are intimately connected to the ocean which nourishes their daily life and culture. Their reliance on fish raises the issue of potential exposure to harmful natural and anthropogenic contaminants as well as providing essential nutrients. The purpose of this study was to assess the risks and benefits of fish consumption in French Polynesia. This cross-sectional study included 195 adults aged 18 years old and over from the Tahiti and Moorea islands. Fatty acids, selenium (Se) and mercury (Hg) blood concentrations were measured in participants and were all very high. Blood concentrations indicate that Hg, Se and omega-3 fatty acids have a common origin, i.e. fish consumption. In comparing the Polynesian group with northern populations, we found that the Polynesian group had levels of Hg similar to those observed in Inuit populations (geometric mean (range): 90.3 (15-420) nmol/L vs. Inuit: m(r): 79.6 (4-560) nmol/L). Similar results were observed with Se blood concentrations. The fatty acid concentration was also similar to that of the Inuit population even though the specific profile of fatty acids differed. For the first time, we report very high blood concentrations of mercury, selenium and omega-3 fatty acids in a fishing population from the South Pacific, comparable to those reported among fishing populations from the Northern hemisphere. Further work is ongoing to better substantiate public health nutritional policies. [ABSTRACT FROM AUTHOR]

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The health of the Inuit has undergone substantial changes over the past five centuries, as a result of social, cultural, and economic changes brought about by interactions with Europeans. This process was accelerated considerably in the second half of the twentieth century. The incidence of infectious diseases has declined considerably but is still high compared with Western societies. Chronic diseases such as diabetes and cardiovascular disease are on the increase, while accidents, suicides, violence, and substance abuse are of major importance for the pattern of ill health in most Inuit communities. Lifestyle changes, social change, and changes in society and the environment are major determinants of health among the Inuit. [ABSTRACT FROM AUTHOR]