Objectives To examine the relation of cord plasma docosahexaenoic acid (DHA) concentration to gestation length, birth size, growth, and infant visual acuity, cognitive, and motor development and the ...effects on growth and development associated with DHA intake from breast-feeding. Study design DHA, other polyunsaturated fatty acids, and 3 environmental contaminants (polychlorinated biphenyls, mercury, and lead) were assessed in cord plasma and maternal plasma and milk in 109 Inuit infants in Arctic Quebec. Multiple regression was used to examine the relation of cord DHA and DHA from breast-feeding on growth and development at 6 and 11 months, after controlling for contaminant exposure and other potential confounders. Results Higher cord DHA concentration was associated with longer gestation, better visual acuity and novelty preference on the Fagan Test at 6 months, and better Bayley Scale mental and psychomotor performance at 11 months. By contrast, DHA from breast-feeding was not related to any indicator of cognitive or motor development in this full-term sample. Conclusions The association of higher cord DHA concentration with more optimal visual, cognitive, and motor development is consistent with the need for substantial increases in this critically important fatty acid during the third trimester spurt of synaptogenesis in brain and photoreceptor development.
Breast cancer (BC) is the most common cancer for women in the western world. From very few cases an extraordinary increase in BC was observed in the Inuit population of Greenland and Canada although ...still lower than in western populations. Previous data suggest that exposure to persistent organic pollutants (POPs) might contribute to the risk of BC. Rat studies showed that perfluorinated compounds (PFCs) cause significantly increase in mammary fibroadenomas. This study aimed at evaluating the association between serum levels of POPs/PFCs in Greenlandic Inuit BC cases and their controls, and whether the combined POP related effect on nuclear hormone receptors affect BC risk.
Thirty-one BC cases and 115 controls were sampled during 2000-2003 from various Greenlandic districts. The serum levels of POPs, PFCs, some metals and the combined serum POP related effect on estrogen- (ER), androgen- (AR) and Ah-receptor (AhR) transactivity were determined. Independent student t-test was used to compare the differences and the odds ratios were estimated by unconditional logistic regression models.
We observed for the very first time a significant association between serum PFC levels and the risk of BC. The BC cases also showed a significantly higher concentration of polychlorinated biphenyls at the highest quartile. Also for the combined serum POP induced agonistic AR transactivity significant association to BC risk was found, and cases elicited a higher frequency of samples with significant POP related hormone-like agonistic ER transactivity. The AhR toxic equivalent was lowest in cases.
The level of serum POPs, particularly PFCs, might be risk factors in the development of BC in Inuit. Hormone disruption by the combined serum POP related xenoestrogenic and xenoandrogenic activities may contribute to the risk of developing breast cancer in Inuit. Further investigations are needed to document these study conclusions.
Motor deficits have frequently been reported in methylmercury (MeHg) poisoning in adults. However, whether exposure to neurotoxic contaminants from environmental sources early in life is associated ...with neuromotor impairments has received relatively little attention. This study examines the relation of developmental exposure to MeHg, polychlorinated biphenyls (PCBs), and lead to motor function in school-age Inuit children exposed through their traditional diet.
In a prospective study in Nunavik, children (mean age=11.3years) were assessed on a battery of fine motor tasks, namely the Stanford-Binet Copying subtest (N=262), the Santa Ana Form Board, and the Finger Tapping Test (N=215). The relation of mercury (Hg; as an index of MeHg exposure), PCB congener 153 (PCB153), and lead concentrations in cord and current blood samples to task performance was examined using linear regression analyses.
After adjustment for potential confounders and control for the other contaminants, higher current PCB concentrations were associated with poorer Santa Ana Form Board and Finger Tapping performance. Results were virtually identical when PCB153 was replaced by other PCB congeners. Higher current Hg levels were independently associated with poorer Finger Tapping performance.
This is the first prospective longitudinal study in children to provide evidence of neuromotor impairments associated with postnatal exposure to seafood contaminants from environmental sources. Fine motor speed appears particularly sensitive to the effects of postnatal PCB exposure, which is unusually high in this population. Results with postnatal MeHg are concordant with previous cross-sectional studies with children and adults.
•Fine motor function was assessed in school-aged children from Nunavik.•Postnatal PCBs were related to poorer manual dexterity and slower fine motor speed.•Postnatal Hg exposure was independently associated with slower fine motor speed.•There was no synergistic effect between the contaminants on motor outcomes.
We examined the relation of household crowding to food insecurity among Inuit families with school-aged children in Arctic Quebec.
We analyzed data collected between October 2005 and February 2010 ...from 292 primary caregiver-child dyads from 14 Inuit communities. We collected information about household conditions, food security, and family socioeconomic characteristics by interviews. We used logistic regression models to examine the association between household crowding and food insecurity.
Nearly 62% of Inuit families in the Canadian Arctic resided in more crowded households, placing them at risk for food insecurity. About 27% of the families reported reducing the size of their children's meals because of lack of money. The likelihood of reducing the size of children's meals was greater in crowded households (odds ratio=3.73; 95% confidence interval=1.96, 7.12). After we adjusted for different socioeconomic characteristics, results remained statistically significant.
Interventions operating across different levels (community, regional, national) are needed to ensure food security in the region. Targeting families living in crowded conditions as part of social and public health policies aiming to reduce food insecurity in the Arctic could be beneficial.
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.
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.
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.
The Inuit population is often described as being protected against CVD due to their traditional dietary patterns and their unique genetic background. The objective of the present study was to examine ...gene-diet interaction effects on plasma lipid levels in the Inuit population. Data from the Qanuippitaa Nunavik Health Survey (n 553) were analysed via regression models which included the following: genotypes for thirty-five known polymorphisms (SNP) from twenty genes related to lipid metabolism; dietary fat intake including total fat (TotFat) and saturated fat (SatFat) estimated from a FFQ; plasma lipid levels, namely total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C) and TAG. The results demonstrate that allele frequencies were different in the Inuit population compared with the Caucasian population. Further, seven SNP (APOA1 - 75G/A (rs670), APOB XbAI (rs693), AGT M235T (rs699), LIPC 480C/T (rs1800588), APOA1 84T/C (rs5070), PPARG2 - 618C/G (rs10865710) and APOE 219G/T (rs405509)) in interaction with TotFat and SatFat were significantly associated with one or two plasma lipid parameters. Another four SNP (APOC3 3238C>G (rs5128), CETP I405V (rs5882), CYP1A1 A4889G (rs1048943) and ABCA1 Arg219Lys (rs2230806)) in interaction with either TotFat or SatFat intake were significantly associated with one plasma lipid variable. Further, an additive effect of these SNP in interaction with TotFat or SatFat intake was significantly associated with higher TC, LDL-C or TAG levels, as well as with lower HDL-C levels. In conclusion, the present study supports the notion that gene-diet interactions play an important role in modifying plasma lipid levels in the Inuit population.
► Mercury was associated with decreased heart rate variability during childhood. ► No association was observed between mercury during childhood and blood pressure. ► Mercury in cord blood was not ...associated with blood pressure. ► Mercury in cord blood was not associated with heart rate variability.
Studies conducted in the Faeroe Islands and Japan suggest a negative impact of mercury on heart rate variability (HRV) among children while the results regarding blood pressure (BP) are less consistent.
To assess the impact of mercury on HRV and BP among Nunavik Inuit children.
A cohort of 226 children was followed from birth to 11 years old. Mercury concentration in cord blood and in blood and hair at 11 years old were used as markers of prenatal and childhood exposure, respectively. HRV was measured using ambulatory 2h-Holter monitoring while BP was measured through a standardized protocol. Simple regression was used to assess the relationship of mercury to BP and HRV parameters. Multiple linear regressions were performed adjusting for covariates such as age, sex, birth weight, body mass index (BMI), height, total n-3 fatty acids, polychlorinated biphenyls (PCB 153), lead, selenium and maternal smoking during pregnancy.
Median cord blood mercury and blood mercury levels at 11 years old were 81.5nmoL/L (IQR: 45.0–140.0) and 14.5nmol/L (IQR: 7.5–28.0), respectively. After adjusting for the covariates, child blood mercury was associated with low frequency (LF) (β=−0.21, p=0.05), the standard deviation of R–R intervals (SDNN) (β=−0.26, p=0.02), the standard deviation of R–R intervals measured over 5min periods (SDANN) (β=−0.31, p=0.01) and the coefficient of variation of R–R intervals (CVRR) (β=−0.06, p=0.02). No significant association was observed with BP.
Mercury exposure during childhood seems to affect HRV among Nunavik Inuit children at school age.
Mercury is a contaminant that reaches high levels in Nunavik (North of Quebec). It is transformed into methylmercury (MeHg) and accumulated in marine mammals and predator fish, an important part of ...the traditional Inuit diet. MeHg has been suggested to affect BP in adults and children while the influence on HRV has only been studied in children. We aimed to assess the impact of MeHg levels on HRV and BP in Inuit adults from Nunavik.
In the fall of 2004, the <<Qanuippitaa?>> Health Survey was conducted in Nunavik (Quebec, Canada) and information on HRV was collected among 280 adults aged 40 years and older. Indicators of the time and frequency domains of HRV were derived from a 2-hour Holter recording. BP was measured according to the Canadian Coalition for High Blood Pressure technique. Pulse pressure (PP) was the difference between systolic (SBP) and diastolic blood pressure (DBP). Blood mercury concentration was used as exposure biomarker. Statistical analysis was conducted through linear regression and multivariable linear regression was used to control for confounders.
Mercury was negatively correlated with low frequency (LF) (r = -0.18; p = 0.02), the standard deviation of RR intervals (SDNN) (r = -0.14; p = 0.047) and the coefficient of variation of RR intervals (CVRR) (r = -0.18; p = 0.011) while correlations with other HRV parameters did not reach statistical significance. After adjusting for confounders, the association with LF (beta = -0.006; p = 0.93) became non significant. However, the association with SDANN became statistically significant (beta = -0.086; p = 0.026) and CVRR tended to decrease with blood mercury concentrations (beta = -0.057; p = 0.056). Mercury was positively correlated with SBP (r = 0.25; p < 0.0001) and PP (r = 0.33; p < 0.0001). After adjusting for confounders, these associations remained statistically significant (beta SBP = 4.77; p = 0.01 and beta PP = 3.40; p = 0.0036). Moreover, most of the HRV parameters correlated well with BP although SBP the best before adjustment for mercury exposure.
The results of this study suggest a deleterious impact of mercury on BP and HRV in adults. SBP and PP increased with blood mercury concentrations while SDANN decreased with blood mercury concentrations.
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