Rotranslational dynamics of confined water. II. Spectroscopic evidence of confinement effects on the far-infrared spectra of water isotopologues in argon and krypton matrices.

Water molecules trapped in rare gas matrices exhibit conspicuous shifts in their far-infrared (FIR), rotranslational spectral features compared with the corresponding transitions observed in the gas phase. These confinement-induced perturbations have been related not only to the quantization of translational motion but also to the coupling between the orientational and positional degrees of freedom: the rotation-translation coupling (RTC). As the propensity displayed by the nuclear spin isomers (NSI) of water to undergo interconversion in confinement is intimately related to how its nuclear spin degrees of freedom are coupled with those for intra- and intermolecular motions, confinement-induced RTC should also strongly impact the NSI interconversion mechanisms and rates. Insight into the rotranslational dynamics for H2 16O, H2 17O, and H2 18O, confined in argon and krypton matrices, is provided here based on the evolution of rotranslational spectra induced by NSI interconversion while a definitive assignment is provided from the transition energies and intensities calculated using the confined rotor model [Paper I, Wespiser et al., J. Chem. Phys. 156, 074304 (2021)]. In order to build a complete rotranslational energy diagram of confined water, which is fundamental to understand the NSI interconversion rates, the energy difference between the ground ortho and para rotranslational states is derived from the temperature dependence of the intensity ratio of mid-infrared lines emerging from these states. These investigations should provide deeper insight of the factors that control NSI interconversion of water isotopologues under extreme confinement.

Association between exposure to persistent organic pollutants and mercury, and glucose metabolism in two Canadian Indigenous populations.

BACKGROUND: The body burden of metals and persistent organic pollutants (POPs) is particularly high in populations that rely on fish and other marine species for sustenance. This exposure has been associated with an increased risk of type 2 diabetes, but results remain contrasted. OBJECTIVE: We studied this association in two Indigenous populations of northern Québec (Canada) with markedly different prevalences of diabetes and levels of exposure to POPs and mercury. METHODS: As part of health surveys conducted in 2004-2009, diabetes prevalence and glucose metabolism (glucose, insulin, HOMA-IR, HOMA-B) in non-diabetic fasting adults were assessed using similar protocols in two populations: Inuit from Nunavik (n = 877) and Cree from Eeyou Istchee territory (n = 780). Blood mercury, plasma polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides/metabolites and polybrominated diphenylethers (PBDEs) levels were measured in samples collected at the time of examination. Logistic and linear regressions and restricted cubic splines analyses were conducted adjusting for sex, age, waist circumference, smoking and omega-3 fatty acid content in plasma phospholipids. RESULTS: Diabetes prevalence was higher in Cree (20%) than in Inuit (7%), whereas environmental exposure was 2 to 3-fold greater in Inuit than in Cree participants. In the range of exposure common to the two populations, we observed similar linear increases in the risk of diabetes with increasing contaminant exposure. Among Cree participants, fasting glucose was positively associated with plasma PBDE level, and HOMA-B negatively associated with concentrations of ∑PCBs, dichlorodiphenyldichloroethylene, PBDEs and ∑OC pesticides. Among Inuit participants, a trend towards reduced insulin secretion was observed in association with most contaminants, but the relation was nonlinear (greater reduction at intermediate levels of exposure). A significant increase in fasting glucose levels was observed at elevated blood mercury levels (>16 µg/L). CONCLUSION: The observed association between POPs exposure and diabetes risk in the two populations studied should be confirmed using prospective design. Our results suggest the need for additional research on the physiopathological process through which POPs exposure may induce type 2 diabetes in these Indigenous populations.

A magnetically focused molecular beam source for deposition of spin-polarised molecular surface layers.

Separating molecular spin isomers is a challenging task, with potential applications in various fields ranging from astrochemistry to magnetic resonance imaging. A new promising method for spin-isomer separation is magnetic focusing, a method which was shown to be capable of producing a molecular beam of ortho-water. Here, we present results from a modified magnetic focusing apparatus and show that it can be used to separate the spin isomers of acetylene and methane. From the measured focused profiles of the molecular beams and a numerical simulation analysis, we provide estimations for the spin purity and the significantly improved molecular flux obtained with the new setup. Finally, we discuss the spin-relaxation conditions which will be needed to apply this new source for measuring nuclear magnetic resonance signals of a single surface layer.

Arsenic exposure and type 2 diabetes: results from the 2007-2009 Canadian Health Measures Survey.

INTRODUCTION: Inorganic arsenic and its metabolites are considered dangerous to human health. Although several studies have reported associations between low-level arsenic exposure and diabetes mellitus in the United States and Mexico, this association has not been studied in the Canadian population. We evaluated the association between arsenic exposure, as measured by total arsenic concentration in urine, and the prevalence of type 2 diabetes (T2D) in 3151 adult participants in Cycle 1 (2007-2009) of the Canadian Health Measures Survey (CHMS). METHODS: All participants were tested to determine blood glucose and glycated hemoglobin. Urine analysis was also performed to measure total arsenic. In addition, participants answered a detailed questionnaire about their lifestyle and medical history. We assessed the association between urinary arsenic levels and T2D and prediabetes using multivariate logistic regression while adjusting for potential confounders. RESULTS: Total urinary arsenic concentration was positively associated with the prevalence of T2D and prediabetes: adjusted odds ratios were 1.81 (95% CI: 1.12-2.95) and 2.04 (95% CI: 1.03-4.05), respectively, when comparing the highest (fourth) urinary arsenic concentration quartile with the lowest (first) quartile. Total urinary arsenic was also associated with glycated hemoglobin levels in people with untreated diabetes. CONCLUSION: We found significant associations between arsenic exposure and the prevalence of T2D and prediabetes in the Canadian population. Causal inference is limited due to the cross-sectional design of the study and the absence of long-term exposure assessment.

TITRE: Exposition à l'arsenic et diabète de type 2 : résultats de l'Enquête canadienne sur les mesures de la santé de 2007 à 2009. INTRODUCTION: L'arsenic inorganique et ses métabolites sont considérés comme dangereux pour la santé humaine. Même si plusieurs études ont indiqué des associations entre une faible exposition à l'arsenic et le diabète sucré aux États-Unis et au Mexique, ces associations n'ont pas été étudiées chez les Canadiens. Nous avons analysé l'association entre l'exposition à l'arsenic, mesurée par la concentration d'arsenic total dans l'urine, et la prévalence du diabète de type 2 (DT2) chez 3 151 participants adultes du cycle 1 (2007 à 2009) de l'Enquête canadienne sur les mesures de la santé (ECMS). MÉTHODOLOGIE: La glycémie et l'hémoglobine glycosylée ont été mesurées chez les participants. L'arsenic total a été dosé par une analyse d'urine. De plus, les participants ont répondu à un questionnaire détaillé sur leurs habitudes de vie et leurs antécédents médicaux. Nous avons analysé l'association de la concentration urinaire d'arsenic avec le DT2 et le prédiabète à l'aide d'une régression logistique multivariée ajustée pour les facteurs de confusion potentiels. RÉSULTATS: La concentration urinaire d'arsenic total était positivement associée à la prévalence de DT2 et de prédiabète : les rapports de cotes ajustés étaient respectivement de 1,81 (IC à 95% : 1,12 à 2,95) et de 2,04 (IC à 95% : 1,03 à 4,05) lorsqu'on comparait les concentrations urinaires d'arsenic les plus élevées (quatrième quartile) aux plus faibles (premier quartile). L'arsenic total urinaire était également associé au taux d'hémoglobine glycosylée chez les diabétiques non traités. CONCLUSION: Nous avons noté des associations significatives entre l'exposition à l'arsenic et la prévalence de DT2 et de prédiabète dans la population canadienne. L'inférence causale est limitée car il s'agit d'une étude transversale exempte d'évaluation de l'exposition à long terme.

Local country food sources of methylmercury, selenium and omega-3 fatty acids in Nunavik, Northern Quebec.

Country foods are central to Inuit culture and replete in selenium (Se) and long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA). However, some marine country foods bioaccumulate high concentrations of methylmercury (MeHg). Se and n-3 are associated with several health benefits in Nunavik, Northern Quebec, but, recent studies show that prenatal MeHg exposure is associated with visual, cognitive and behavioral deficit later in childhood. The study objectives are to identify contemporary country food sources of MeHg, Se and long-chain n-3 PUFA in Nunavik, particularly among childbearing-age women, taking into account regional differences in consumption profiles. The contribution of different country foods to daily MeHg, Se, long-chain n-3 PUFA intake (µg/kg body weight/day) was estimated using: (i) country food consumption and blood biomarkers data from the 2004 Nunavik Health Survey (387 women, 315 men), and (ii) data on MeHg, Se, long-chain n-3 PUFA concentrations found in Nunavik wildlife species. In the region where most traditional beluga hunting takes place in Nunavik, the prevalence of at-risk blood Hg (≥ 8 µg/L) in childbearing-age women was 78.4%. While most country foods presently consumed contain low MeHg, beluga meat, not a staple of the Inuit diet, is the most important contributor to MeHg: up to two-thirds of MeHg intake in the beluga-hunting region (0.66 of MeHg intake) and to about one-third in other regions. In contrast, seal liver and beluga mattaaq - beluga skin and blubber - only mildly contributed to MeHg (between 0.06 and 0.15 of MeHg intake), depending on the region. Beluga mattaaq also highly contributed to Se intake (0.30 of Se intake). Arctic char, beluga blubber and mattaaq, and seal blubber contributed to most long-chain n-3 PUFA intake. This study highlights the importance of considering interconnections between local ecosystems and dietary habits to develop recommendations and interventions promoting country foods' benefits, while minimizing the risk of MeHg from beluga meat, especially for childbearing-age women.

Saturated and monounsaturated fatty acid status is associated with bone strength estimated by calcaneal ultrasonography in Inuit women from Nunavik (Canada): a cross-sectional study.

OBJECTIVE: The aim of this study is to examine the relationship between the status in selected saturated (SFAs) and monounsaturated (MUFAs) fatty acids and the Stiffness Index (SI) in Inuit women from Nunavik (Northern Quebec, Canada). DESIGN: Cross-sectional descriptive study. SETTING: Inuit population from 14 communities who participated to Qanuippitaa? How are we? Nunavik Inuit Health Survey in 2004. PARTICIPANTS: 187 Inuit women aged 35-72 years. MEASUREMENTS: SI was determined by ultrasonography (Achilles InSight device) at the right calcaneus of participants. SFAs and MUFAs contents of erythrocyte membrane phospholipids were measured after transmethylation by gas chromatography coupled with a flame ionization detector. Several factors known to be associated with bone strength were concomitantly recorded. Multiple linear regression was used to investigate relations between selected SFAs, MUFAs and SI, taking into consideration several potential confounders and covariates. RESULTS: Total SFAs, in particular behenic acid, and cis-vaccenic acid among MUFAs were negatively associated with SI (ß = -0.028, SE = 0.011, p = 0.0084; ß = -0.060, SE = 0.023, p = 0.0093 and ß = -0.087, SE = 0.019, p <0.0001, respectively), whereas total cis-MUFAs and specifically oleic acid were positively associated with SI (ß = 0.036, SE = 0.011, p = 0.0008; ß = 0.037, SE = 0.011, p = 0.0014, respectively) after adjustment for several covariates. CONCLUSION: Saturated and monounsaturated fatty acid status is associated with bone strength estimated by calcaneal SI values in Inuit women from Nunavik.

[Not Available]. / Le statut en acide eicosapentaénoïque est associé à des valeurs plus élevées de l'indice calcanéen ultrasonore stiffness chez les femmes autochtones: résultats d'une étude longitudinale et de deux études transversales.

Several studies have reported that the status in omega-3 polyunsaturated fatty acid (PUFA) and the omega-3/omega-6 PUFA ratio are positively related to bone health. This study aimed at examining the relationship between the status of different PUFAs and bone strength expressed by the stiffness index (SI) among indigenous women in northern Canada and Greenland, whose diets are rich in PUFAs compared to those of non-Aboriginals. Our study includes 118 Inuit women from Nuuk (Greenland), 195 Inuit women from Nunavik (Canada), and 249 Cree women of from East James Bay (Canada). Projects in Nunavik and in the Cree communities had a cross-sectional design and the Greenland project, a longitudinal design. The content of some PUFAs phospholipids of erythrocyte membranes was measured after transmethylation by gas chromatography coupled with a flame ionization detector. Stiffness index was measured by ultrasound at the right calcaneus with a water-bath Achilles Lunar instrument (Greenland) or an Achilles Insight instrument (Nunavik, East James Bay). Relations between SI and various PUFAs were studied using multiple linear regression analyses. Eicosapentaenoic acid (EPA) was positively and significantly associated with SI (log), even after adjustment for several confounders and covariates in all three projects. A high EPA status, resulting mainly from the consumption of fatty fish or marine mammal fat, seems to have a positive effect on bone strength measured by ultrasonography among Aboriginal women from three different populations.

Persistent organic pollutants and transthyretin-bound thyroxin in plasma of Inuit women of childbearing age.

The Inuit population of Nunavik (Northern Quebec, Canada) is highly exposed to persistent organic pollutants (POPs) through their traditional diet. Some POPs, i.e., hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs), pentachlorophenol (PCP), and perfluorooctane sulfonate (PFOS), compete with thyroxin (T4) for binding sites on transthyretin (TTR), a T4 transport protein found in plasma and cerebrospinal fluid. We tested the hypothesis that these TTR-binding compounds decrease circulating concentrations of T4 bound to TTR (T4-TTR) in Inuit women of reproductive age. We measured the concentration of T4-TTR in plasma samples obtained from 120 Inuit women (18-39 years old) by combining native-polyacrylamide gel electrophoresis and liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. Total T4, TTR, and thyroxin-binding globulin (TBG) concentrations were also determined, while POPs levels had been previously measured. The mean T4-TTR concentration was 8.4 nmol/L (SD = 2.4) with values ranging from 2.9 to 14.4 nmol/L. Linear regression analysis revealed that TTR, TBG, and total T4 concentrations were significant predictors (p < 0.002) of T4-TTR levels (total adjusted R-squared = 0.26, p < 0.0001) but not levels of OH-PCBs, chlorophenols, or PFOS. Our results suggest that circulating levels of these TTR-binding compounds in Inuit women of childbearing age are not high enough to affect TTR-mediated thyroid hormone transport. The possibility of increased delivery of these compounds to the developing brain requires further investigation.

Environmental contaminants and human health in the Canadian Arctic.

The third Canadian Arctic Human Health Assessment conducted under the Canadian Northern Contaminants Program (NCP), in association with the circumpolar Arctic Monitoring and Assessment Programme (AMAP), addresses concerns about possible adverse health effects in individuals exposed to environmental contaminants through a diet containing country foods. The objectives here are to: 1) provide data on changes in human contaminant concentrations and exposure among Canadian Arctic peoples; 2) identify new contaminants of concern; 3) discuss possible health effects; 4) outline risk communication about contaminants in country food; and 5) identify knowledge gaps for future contaminant research and monitoring. The nutritional and cultural benefits of country foods are substantial; however, some dietary studies suggest declines in the amount of country foods being consumed. Significant declines were found for most contaminants in maternal blood over the last 10 years within all three Arctic regions studied. Inuit continue to have the highest levels of almost all persistent organic pollutants (POPs) and metals among the ethnic groups studied. A greater proportion of people in the East exceed Health Canada's guidelines for PCBs and mercury, although the proportion of mothers exceeding these guidelines has decreased since the previous assessment. Further monitoring and research are required to assess trends and health effects of emerging contaminants. Infant development studies have shown possible subtle effects of prenatal exposure to heavy metals and some POPs on immune system function and neurodevelopment. New data suggest important beneficial effects on brain development for Inuit infants from some country food nutrients. The most successful risk communication processes balance the risks and benefits of a diet of country food through input from a variety of regional experts and the community, to incorporate the many socio-cultural and economic factors to arrive at a risk management decision that will be the most beneficial in Arctic communities.

Alteration of infant attention and activity by polychlorinated biphenyls: unravelling critical windows of susceptibility using physiologically based pharmacokinetic modeling.

Pre- and postnatal exposure to polychlorinated biphenyls (PCBs) can impair behavioural function in animal models at doses within the range at which humans are commonly exposed. Yet, epidemiologic studies conducted in the US and Europe are inconsistent with regard to the developmental effects of lactational exposure to these chemicals. This inconsistency may be due to limitations in the current methodological approaches for assessing postnatal exposure to PCBs. Our study used a physiologically based pharmacokinetic (PBPK) model to simulate blood PCB levels during specific pre- and postnatal periods and to evaluate the relation of those levels to infant behaviour. A previously validated PBPK model was used to simulate infant blood PCB-153 levels at delivery and on a month-by-month basis during the first year of life for Inuit infants enrolled in a longitudinal birth cohort. Infant behaviour was assessed using the Behaviour Rating Scales (BRS) of the Bayley Scales of Infant Development (BSID-II) at 11 months of age and video coding of inattention and activity measured during the administration of the mental development subscale of the BSID-II. The estimated pre- and postnatal PCB exposure measures predicted significant increases in inattention and activity at 11 months. Whereas inattention was related to prenatal exposure, activity level, measured by non-elicited activity, was best predicted by postnatal exposure, with the strongest association obtained for simulated PCB levels during the 4th month of life. These findings are consistent with previous reports indicating PCB-induced behavioural alteration in attention and activity level. Simulated infant toxicokinetic profiles for the first year of life revealed windows of susceptibility during which PCBs may impair infant attention and activity.

The relation of environmental contaminants exposure to behavioral indicators in Inuit preschoolers in Arctic Quebec.

Although lead (Pb) exposure has been identified as an important risk factor in child behavioral development, less is known regarding the relation between child behavior and exposure to polychlorinated biphenyls (PCBs) and mercury (Hg). Inuit children are particularly exposed to these chemicals and the aim of this study was to investigate the association between prenatal and postnatal exposure to Pb, PCBs, Hg and several aspects of behavioral function in Inuit preschoolers. The sample consisted of one hundred and ten 5-year-old Inuit children from Arctic Quebec. An umbilical cord blood sample was used to document prenatal exposure to Pb, PCBs and Hg. Child blood samples were collected at age 5 and the same contaminants were measured. A modified version of the Infant Behavior Rating Scale from the Bayley Scales of Infant Development-II was used to assess child behavior through examiners' ratings. Furthermore, attention, activity and emotional outcomes were assessed through behavioral coding of video recordings taken during fine motor testing. Pb exposure during childhood was associated with examiners ratings of greater impulsivity, irritability and with coding of observed inattention. Prenatal exposure to PCB 153 correlated with the examiners ratings of increased state of unhappiness and anxiety during the testing session, which was corroborated from video coding since cord PCB 153 was related to fewer manifestations of positive affects. No association was found with Hg exposure. These data corroborated those from previous Pb cohort studies and revealed an association between prenatal PCBs exposure and emotional outcomes in preschoolers.

The relation of low-level prenatal lead exposure to behavioral indicators of attention in Inuit infants in Arctic Quebec.

The aim of this study was to investigate the association between prenatal exposure to lead (Pb) and several aspects of behavioral function during infancy through examiner ratings and behavioral coding of video recordings. The sample consisted of 169 11-month-old Inuit infants from Arctic Quebec. Umbilical cord and maternal blood samples were used to document prenatal exposure to Pb. Average blood Pb levels were 4.6 mug/dL and 5.9 mug/dL in cord and maternal samples respectively. The Behavior Rating Scales (BRS) from the Bayley Scales of Infant Development (BSID-II) were used to assess behavior. Attention was assessed through the BRS and behavioral coding of video recordings taken during the administration of the BSID-II. Whereas the examiner ratings of behaviors detected very few associations with prenatal Pb exposure, cord blood Pb concentrations were significantly related to the direct observational measures of infant attention, after adjustment for confounding variables. These data provide evidence that increasing the specificity and the precision of the behavioral assessment has considerable potential for improving our ability to detect low-to-moderate associations between neurotoxicants, such Pb and infant behavior.

Risk and benefits from consuming salmon and trout: a Canadian perspective.

Recent reports on the presence of persistent organic chemicals in wild and farmed salmon have left consumers and health professionals confused regarding the safety of regular fish consumption. The objectives of this study were (1) to compare concentrations of key contaminants and the essential nutrients omega-3 fatty acids between farmed and wild salmon and trout, and (2) to balance risks and benefits from regularly consuming these species. Concentrations of mercury, polychlorinated biphenyls, dioxins and furans as well as omega-3 fatty acids were determined in fillets from farmed salmon and trout bought in various markets located in Quebec, Canada, as well as in fillets from wild salmonids obtained from fishermen and various Canadian agencies. While differences were observed between market (farmed) and wild fish with regard to the concentrations of mercury and polychlorinated biphenyls, overall the concentrations of contaminants were low, such that the regular consumption of these fish would not cause tolerable daily intakes to be exceeded. Our results indicate that salmon and trout sold in Quebec markets, which as in markets located elsewhere in North America originate for the most part from Chilean farms, can be consumed regularly to achieve optimal nutritional benefits from omega-3 fatty acids, without incurring significant contaminant related health risks.

Human health implications of environmental contaminants in Arctic Canada: A review.

The objectives of this paper are to: assess the impact of exposure to current levels of environmental contaminants in the Canadian Arctic on human health; identify the data and knowledge gaps that need to be filled by future human health research and monitoring; examine how these issues have changed since our first assessment [Van Oostdam, J., Gilman, A., Dewailly, E., Usher, P., Wheatley, B., Kuhnlein, H. et al., 1999. Human health implications of environmental contaminants in Arctic Canada: a review. Sci Total Environ 230, 1-82]. The primary exposure pathway for contaminants for various organochlorines (OCs) and toxic metals is through the traditional northern diet. Exposures tend to be higher in the eastern than the western Canadian Arctic. In recent dietary surveys among five Inuit regions, mean intakes by 20- to 40-year-old adults in Baffin, Kivalliq and Inuvialuit communities exceeded the provisional tolerable daily intakes (pTDIs) for the OCs, chlordane and toxaphene. The most recent findings in NWT and Nunavut indicate that almost half of the blood samples from Inuit mothers exceeded the level of concern value of 5 microg/L for PCBs, but none exceeded the action level of 100 microg/L. For Dene/Métis and Caucasians of the Northwest Territories exposure to OCs are mostly below this level of concern. Based on the exceedances of the pTDI and of various blood guidelines, mercury and to a lesser extent lead (from the use of lead shot in hunting game) are also concerns among Arctic peoples. The developing foetus is likely to be more sensitive to the effects of OCs and metals than adults, and is the age groups of greatest risk in the Arctic. Studies of infant development in Nunavik have linked deficits in immune function, an increase in childhood respiratory infections and birth weight to prenatal exposure to OCs. Balancing the risks and benefits of a diet of country foods is very difficult. The nutritional benefits of country food and its contribution to the total diet are substantial. Country food contributes significantly more protein, iron and zinc to the diets of consumers than southern/market foods. The increase in obesity, diabetes and cardiovascular disease has been linked to a shift away from a country food diet and a less active lifestyle. These foods are an integral component of good health among Aboriginal peoples. The social, cultural, spiritual, nutritional and economic benefits of these foods must be considered in concert with the risks of exposure to environmental contaminants through their exposure. Consequently, the contamination of country food raises problems which go far beyond the usual confines of public health and cannot be resolved simply by risk-based health advisories or food substitutions alone. All decisions should involve the community and consider many aspects of socio-cultural stability to arrive at a decision that will be the most protective and least detrimental to the communities.

Increase in plasma pollutant levels in response to weight loss is associated with the reduction of fasting insulin levels in men but not in women.

Environmental pollutants can act as endocrine modulators. In this study, we examined whether weight loss-induced changes in plasma organochlorine compounds (OC) were associated with those in plasma insulin levels. Fasting insulin and the area under the curve (AUC) of insulin after a 75-g oral glucose load, plasma levels of 1 commercial polychlorinated biphenyl (PCB) mixture (Aroclor 1260), 1 PCB congener (PCB 153), and 3 pesticides (2,2'-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), beta-hexachlorocyclohexane (beta-HCH), and hexachlorobenzene (HCB)) were measured before and after a 15-week weight loss program induced by a caloric restriction in a sample of obese men and women. Both genders showed a similar reduction in body weight (approximately 11 kg) in response to treatment, although men lost significantly more fat mass than women (mean +/- SD 9.4 +/- 4.1 v 5.9 +/- 5 kg, respectively, P <.05). Fasting insulin and AUC of insulin significantly decreased in men and women after the treatment. In response to weight loss, a significant increase in OC was observed in both genders, and this effect was more pronounced in men. The greater the increase in plasma OC levels, the greater the reduction in fasting insulin was in response to weight loss in men (-.49 < r < -.59, P <.05), but not in women (-.22 < r <.01, not significant [NS]). In both genders, no relationship was observed between changes in plasma OC levels and changes in AUC of insulin (-.41 < r < -.08, NS). In men, relationships between changes in plasma HCB, Aroclor 1260, and PCB-153 concentrations and those in fasting insulin levels in response to weight loss remained significantly correlated after correction for fat mass loss (-.46 < partial r < -.51, P values ranging from.05 to.07). These results suggest that weight loss-induced increase in plasma pollutant levels tends to be independently associated with the reduction of fasting insulin levels in men, but not in women. Further studies are needed to verify whether these findings are causally related.

Increase in plasma pollutant levels in response to weight loss in humans is related to in vitro subcutaneous adipocyte basal lipolysis.

OBJECTIVE: To examine whether weight loss-induced changes in in vitro basal lipolysis of subcutaneous abdominal and femoral fat cells were related to those in plasma organochlorine levels. DESIGN: A 15 week weight loss program induced by a moderate caloric restriction. SUBJECTS: Seventeen men and 20 women (age 36-50 y, body fat 25-50%). MEASUREMENTS: In vitro basal lipolysis of subcutaneous abdominal and femoral adipocytes and plasma levels of five polychlorinated biphenyl congeners (Aroclor 1260, PCBs 118, 138, 153 and 180) and three chlorinated pesticides (dichlorodiphenyl dichloroethene (p,p'-DDE), beta-hexachlorocyclohexane (beta-HCH) and hexachlorobenzene (HCB)) were measured before and after the weight reducing program. RESULTS: Both genders showed a similar reduction in body weight (approximately 11 kg) in response to treatment, although men lost significantly more fat mass than women (mean+/-s.d., 9.4+/-4.1 vs 5.9+/-5 kg, respectively, P<0.05). Mean basal fat cell lipolysis did not vary before and after weight reduction, regardless of depots and genders. In response to weight loss, significant increases of all organochlorines investigated were observed in men, whereas only p,p'-DDE, Aroclor 1260, PCBs 153 and 180 significantly rose in women. In men, higher the increase in basal lipolysis of subcutaneous abdominal or femoral adipocytes, greater the rise in plasma levels of most pollutants (HCB, Aroclor 1260, PCBs 118, 138 and 153) was in response to weight loss (0.51

Prenatal exposure of the northern Québec Inuit infants to environmental contaminants.

The Inuit population residing in Nunavik (northern Québec, Canada) relies on species from the marine food web for subsistence and is therefore exposed to high doses of environmental contaminants such as polychlorinated biphenyls and methylmercury and to a lesser extent lead. In view of the neurotoxic properties of these substances following developmental exposure, we initiated a study on infant development in this remote coastal population. Here we report the magnitude of prenatal exposure to these contaminants and to selective nutrients in Inuit mothers and their newborns who were recruited on the Hudson Bay coast. We conducted interviews during the women's pregnancies and at 1 and 11 months postpartum and collected biological samples for mercury, lead, polychlorinated biphenyls (PCBs), and chlorinated pesticides analyses as well as selenium and N-3 polyunsaturated fatty acids (n3-PUFA). Cord blood, maternal blood, and maternal hair mercury concentrations averaged 18.5 microg/L, 10.4 microg/L, and 3.7 microg/g, respectively, and are similar to those found in the Faroe Islands but lower than those documented in the Seychelles Islands and New Zealand cohorts. Concentrations of PCB congener 153 averaged 86.9, 105.3, and 131.6 microg/kg (lipids) in cord plasma, maternal plasma, and maternal milk, respectively; prenatal exposure to PCBs in the Nunavik cohort is similar to that reported in the Dutch but much lower than those in other Arctic cohorts. Levels of n3-PUFA in plasma phospholipids and selenium in blood are relatively high. The relatively low correlations observed between organochlorine and methylmercury concentrations may make it easier to identify the specific developmental deficits attributable to each toxicant. Similarly, the weak correlations noted between environmental contaminants and nutrients will facilitate the documentation of possible protective effects afforded by either n3-PUFA or selenium against neurotoxic contaminants.

Determinants of polychlorinated biphenyls and methylmercury exposure in inuit women of childbearing age.

The objectives of this study were to to identify maternal characteristics associated with traditional food consumption and to examine food items associated with polychlorinated biphenyls (PCBs) and mercury body burden in pregnant Inuit women from Northern Québec. We interviewed women from three communities at mid-pregnancy and at 1 and 11 months postpartum. We measured PCBs, Hg, and selenium in maternal blood; Hg was also measured in maternal hair. The women reported eating significant amounts of fish, beluga muktuk/fat, seal meat, and seal fat. Although consumption of fish and seal was associated with lower socioeconomic status, consumption of beluga whale was uniform across strata. Fish and seal meat consumption was associated with increased Hg concentrations in hair. Traditional food intake during pregnancy was unrelated to PCB body burden, which is more a function of lifetime consumption. This study corroborated previous findings relating marine mammal and fish consumption to increased Hg and selenium body burden. Despite widespread knowledge regarding the presence of these contaminants in traditional foods, a large proportion of Inuit women increased their consumption of these foods during pregnancy, primarily because of pregnancy-related changes in food preferences and the belief that these foods are beneficial during pregnancy.

n-3 Fatty acids and cardiovascular disease risk factors among the Inuit of Nunavik.

BACKGROUND: Inuit traditionally consume large amounts of marine foods rich in n-3 fatty acids. Evidence exists that n-3 fatty acids have beneficial effects on key risk factors for cardiovascular disease. OBJECTIVE: Our goal was to verify the relation between plasma phospholipid concentrations of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and various cardiovascular disease risk factors among the Inuit of Nunavik, Canada. DESIGN: The study population consisted of 426 Inuit aged 18-74 y who participated in a 1992 health survey. Data were obtained through home interviews and clinical visits. Plasma samples were analyzed for phospholipid fatty acid composition. RESULTS: Expressed as the percentage of total fatty acids, geometric mean concentrations of EPA, DHA, and their combination in plasma phospholipids were 1.99%, 4.52%, and 6.83%, respectively. n-3 Fatty acids were positively associated with HDL-cholesterol concentrations and inversely associated with triacylglycerol concentrations and the ratio of total to HDL cholesterol. In contrast, concentrations of total cholesterol, LDL cholesterol, and plasma glucose increased as n-3 fatty acid concentrations increased. There were no significant associations between n-3 fatty acids and diastolic and systolic blood pressure and plasma insulin. CONCLUSIONS: Consumption of marine products, the main source of EPA and DHA, appears to beneficially affect some cardiovascular disease risk factors. The traditional Inuit diet, which is rich in n-3 fatty acids, is probably responsible for the low mortality rate from ischemic heart disease in this population.

Exposure of the Inuit population of Nunavik (Arctic Quebec) to lead and mercury.

The authors conducted a survey during 1992 to evaluate blood levels of lead and mercury in Inuit adults of Nunavik (Arctic Quebec, Canada). Blood samples obtained from 492 participants (209 males and 283 females; mean age = 35 yr) were analyzed for lead and total mercury; mean (geometric) concentrations were 0.42 micromol/l (range = 0.04-2.28 micromol/l) and 79.6 nmol/l (range = 4-560 nmol/l), respectively. Concentrations of omega-3 fatty acid in plasma phospholipids--a biomarker of marine food consumption--were correlated with mercury (r = .56, p < .001) and, to a lesser extent, with blood lead levels (r = .31, p < .001). Analyses of variance further revealed that smoking, age, and consumption of waterfowl were associated with lead concentrations (r2 = .30, p < .001), whereas age and consumption of seal and beluga whale were related to total mercury levels (r2 = .30, p < .001). A significant proportion of reproductive-age women had lead and mercury concentrations that exceeded those that have been reportedly associated with subtle neurodevelopmental deficits in other populations.