A population-based study on blood lead levels in blood donors.

BACKGROUND: Recent studies suggested that blood transfusion may represent a significant source of lead exposure in premature infants. Objectives of this study were to determine blood lead levels (BLLs) in a representative sample of blood donors and to identify risk factors associated with BLLs of 0.15 µmol/L or more. STUDY DESIGN AND METHODS: A study was conducted in 2006 to 2007 in 49 drive sites in Quebec. Individuals who qualified for blood donation were eligible to participate. Information was harvested from blood donor file and a standardized self-administered questionnaire. Lead analysis was performed by inductively coupled plasma mass spectrometry. Data on Quebec blood donors from 2003 to 2006 (n = 320,543) were used to establish a reference population. Geometric mean (GM) and 95% confidence interval (CI) were used to describe the results. The project was approved by an ethics committee. RESULTS: Of 6715 eligible individuals, 3490 participated (1392 women and 2098 men). Their mean age was 46.5 years. Results were weighted for region, sex, and age. The GM of BLLs was 0.082 µmol/L (95% CI, 0.027-0.247; range, 0.011-2.90 µmol/L). BLLs of more than 0.15 µmol/L were found in 15.5% of participants. In multivariate analysis, BLLs were mainly explained by age and sex of participants (p < 0.001). A significant association was also found between BLLs and the region of residence, education level, dwelling age, occupational and leisure activities at high risk for lead exposure, smoking, and alcohol intake (p < 0.001). CONCLUSION: BLL in blood donors is strongly explained by sex and age, a fact that can be taken into consideration when transfusing neonates.

Contamination of public whirlpool spas: factors associated with the presence of Legionella spp., Pseudomonas aeruginosa and Escherichia coli.

This work explores the factors associated with contamination of public spas by Legionella spp., Pseudomonas aeruginosa and Escherichia coli. Physicochemical and microbiological parameters were measured in water samples from 95 spas inQuébec, Canada. Spa maintenance was documented by a questionnaire. Legionella spp. were detected in 23% of spas, P. aeruginosa in 41% and E. coli in 2%. Bacteria were found in concerning concentrations (Legionella spp. ≥ 500 CFU/l, P. aeruginosa ≥ 51 CFU/100 ml or E. coli ≥ 1 CFU/100 ml) in 26% ofspas. Observed physicochemical parameters frequently differed from recommended guidelines. The following factors decreased the prevalence of concerning microbial contamination: a free chlorine concentration ≥ 2 mg/l or total bromine ≥ 3 mg/l (p = 0.001), an oxidation-reduction potential (ORP) > 650 mV (p = 0.001), emptying and cleaning the spa at least monthly (p = 0.019) and a turbidity ≤ 1 NTU (p = 0.013). Proper regulations and training of spa operators are critical for better maintenance of these increasingly popular facilities.

Maternal exposure to drinking-water chlorination by-products and small-for-gestational-age neonates.

BACKGROUND: There is concern about possible effects of disinfection by-products on reproductive outcomes. The purpose of this study was to evaluate the association between maternal exposure to chlorination by-products and the risk of delivering a small for-gestational-age (SGA) neonate. METHODS: We conducted a population-based case-control study in the Québec City (Canada) area. Term newborn cases with birth weights <10th percentile (n = 571) were compared with 1925 term controls with birth weights ≥10th percentile. Concentrations of trihalomethanes and haloacetic acids in the water-distribution systems of participants were monitored during the study period, and a phone interview on maternal habits was completed within 3 months after childbirth. We estimated chlorination by-products ingestion during the last trimester of pregnancy and trihalomethanes doses resulting from inhalation and dermal exposure. We evaluated associations between chlorination by-products in utero exposure and SGA by means of unconditional logistic regression with control of potential confounders. RESULTS: When total trihalomethanes and the 5 regulated haloacetic acids concentrations were divided into quartiles, no clear dose-response relationship was found with SGA. However, increased risk was observed when haloacetic concentrations were above the fourth quartile and when either trihalomethanes or haloacetic acids concentrations were above current water standards (adjusted OR= 1.5 [95% confidence interval = 1.1-1.9] and 1.4 [1.1-1.9], respectively). Inhalation and dermal absorption of trihalomethanes did not contribute to this risk, but a monotonic dose-response was found with haloacetic acids ingestion. CONCLUSION: Oral exposure to high levels of chlorination by-products in drinking water could be a risk factor for term SGA.

A study of the association between characteristics of CLSCs and the risk of small for gestational age births among term and preterm births in Quebec, Canada.

OBJECTIVES: The objective of this study was to describe whether the social environment of the territory of residence is associated with indicators of foetal growth retardation. METHODS: All newborns (n = 667,254) from 143 Centres locaux de services communautaires (CLSC) territories of Quebec, Canada, 2000-2008 were included in this study. Small for gestational age (SGA), very small for gestational age (VSGA) and SGA-preterm births were identified. Social characteristics and access to medical services of the population in the CLSCs were obtained from the Canadian Community Health Survey. Data on material deprivation, racial diversity and social isolation were obtained from the 2001 and 2006 Canadian censuses. A compromise between two methods, stepwise and best subset, was used to select variables for multivariate logistic modelling. The model was fitted on each studied outcome: SGA, VSGA and SGA among preterm births. RESULTS: When investigating material deprivation, racial diversity, social isolation, proportion of sedentary residents and proportion with fair or poor availability of health care services in the CLSC territories, material deprivation, racial diversity, social isolation and sedentary residents showed increased adjusted risk of SGA. Results of the model fit on VSGA birth and on SGA among preterm births were similar. CONCLUSION: CLSC characteristics of material deprivation, racial diversity, social isolation as well as the contextual variable of sedentary lifestyle were associated with indicators of foetal growth retardation. Further work on features of the CLSCs could help understand how the outcome of SGA is associated with contextual factors and identify groups for intervention.

The association between farming activities, precipitation, and the risk of acute gastrointestinal illness in rural municipalities of Quebec, Canada: a cross-sectional study.

BACKGROUND: Increasing livestock density and animal manure spreading, along with climate factors such as heavy rainfall, may increase the risk of acute gastrointestinal illness (AGI). In this study we evaluated the association between farming activities, precipitation and AGI. METHODS: A cross-sectional telephone survey of randomly selected residents (n = 7006) of 54 rural municipalities in Quebec, Canada, was conducted between April 2007 and April 2008. AGI symptoms and several risk factors were investigated using a phone questionnaire. We calculated the monthly prevalence of AGI, and used multivariate logistic regression, adjusting for several demographic and risk factors, to evaluate the associations between AGI and both intensive farming activities and cumulative weekly precipitation. Cumulative precipitation over each week, from the first to sixth week prior to the onset of AGI, was analyzed to account for both the delayed effect of precipitation on AGI, and the incubation period of causal pathogens. Cumulative precipitation was treated as a four-category variable: high (> or = 90th percentile), moderate (50th to <90th percentile), low (10th to <50th percentile), and very low (<10th percentile) precipitation. RESULTS: The overall monthly prevalence of AGI was 5.6% (95% CI 5.0%-6.1%), peaking in winter and spring, and in children 0-4 years old. Living in a territory with intensive farming was negatively associated with AGI: adjusted odds ratio (OR) = 0.70 (95% CI 0.51-0.96). Compared to low precipitation periods, high precipitation periods in the fall (September, October, November) increased the risk of AGI three weeks later (OR = 2.20; 95% CI 1.09-4.44) while very low precipitation periods in the summer (June, July, August) increased the risk of AGI four weeks later (OR = 2.19; 95% CI 1.02-4.71). Further analysis supports the role of water source on the risk of AGI. CONCLUSIONS: AGI poses a significant burden in Quebec rural municipalities with a peak in winter. Intensive farming activities were found to be negatively associated with AGI. However, high and very low precipitation levels were positively associated with the occurrence of AGI, especially during summer and fall. Thus, preventive public health actions during such climate events may be warranted.

Plasma omega-3 and psychological distress among Nunavik Inuit (Canada).

Marine omega-3 (n-3) fatty acid eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids have been associated with beneficial effects in mental health. Cultural and social changes have been related to a decline in mental health of the Inuit, but the role of diet has received scant attention. We examined the relationship between psychological distress (PD) and plasma n-3 among 368 Nunavik Inuit aged 18-74 years who took part in a survey in 1992. Participants were categorized as high-level PD if they scored over the 80th percentile of the PD Index Santé-Québec Survey (PDISQS-14), and non-distressed subjects were those who scored less than this cutoff. Compared with the non-distressed group, n-3 concentrations in the PD group were significantly lower in women but not in men. Compared with the lowest tertile of EPA + DHA, the odds ratios for high-level PD among women were 0.32 (95% CI: 0.13-0.82) for the second, and 0.30 (95% CI: 0.10-0.90) for the third tertile, after controlling for confounders. In males, there were no significant associations between EPA+DHA and PDISQS-14 scores. Our findings suggest that marine n-3 may play a role in PD among Inuit women. The gender difference observed in our analysis must be examined more carefully in future studies.

Plasma n-3 fatty acids and psychological distress in aboriginal Cree Indians (Canada).

OBJECTIVE: To examine the relationship between psychological distress (PD) and plasma n-3 long-chain (LC) PUFA, i.e. EPA, docosapentaenoic acid (DPAn-3) and DHA. DESIGN: Population-based, cross-sectional Santé-Québec Health Survey (1991). Participants were categorized as high-level PD if they scored over the 80th percentile of the PD Index in the Santé-Québec Survey; non-distressed subjects were those who scored less than this cut-off. Associations between tertiles of n-3 fatty acids (FA) and the risk of high-level PD were expressed as odds ratios, with the lowest tertile as the reference group. SETTING: Québec, Canada. SUBJECTS: Data were analysed from a representative sample of 852 James Bay Cree Indian adults aged 18 years and over. RESULTS: Proportions of n-3 FA were statistically significantly lower in the PD than in the non-distressed group. After adjustment for confounders, EPA was the only individual n-3 FA significantly associated with the risk of high-level PD. Combinations of EPA + DHA or EPA + DPAn-3 + DHA or the sum of n-3 were also associated with the risk of high-level PD. Compared with the lowest tertile of EPA + DHA, the OR for high-level PD was 0.89 (95 % CI 0.59, 1.36) for the second and 0.56 (95 % CI 0.32, 0.98) for the third tertile, after controlling for confounders. CONCLUSIONS: In the present retrospective, cross-sectional study, we found that proportions of n-3 LC PUFA in plasma phospholipids, markers of n-3 LC PUFA consumption from fish, were inversely associated with PD.

Risk of diarrhea with adult residents of municipalities with significant livestock production activities.

BACKGROUND: The intensification of livestock production has led to situations where the amount of manure that is produced exceeds the amounts needed in some areas. The objective of this study was to evaluate the relationship between the intensity of livestock activities and manure products, particularly in swine farms, and the prevalence of diarrhea in adults. METHODS: A survey was carried out on 8702 adults living in 161 municipalities in Quebec areas with intensive farming activities. Data were collected by a telephonic interview on diarrheal symptoms that occurred during the previous week of the interview, on water consumption and on selected risk factors. Statistical analysis was performed using a 'generalized estimating equations' model. RESULTS: Prevalence of diarrhea was found to be highest in adults aged between 25 and 34 years. No association was found between swine density or liquid manure application and diarrheal prevalence. There was also no association between cattle or total animal density and diarrheal prevalence. In the areas studied, there was no increase in risk associated with the consumption of tap water with suboptimal treatment and susceptible to microbiologic contamination. CONCLUSION: Significant livestock production and excess of manure were not associated with the risk of diarrhea in adults.

Drinking water intake by infants living in rural Quebec (Canada).

Drinking water is a potential source of toxic contaminant and it is well known that water intake on a body weight basis decreases rapidly with increasing age. Nevertheless, few studies have been conducted on water intake of very young infants who might be particularly sensitive to some toxic chemicals. The objective of this study was to describe the mean and distribution of total water intake of 2-month old infants living in agricultural areas. Mothers (n=642) of 8 to 9 week old infants were interviewed by phone to evaluate their feeding practice, including juice and cereal intake. There were 393 infants (61%) who drank some quantity of water and 278 (43%) consumed formula reconstituted with water. For formula-fed infants, the 10, 50 and 90th percentiles of daily water intake were 79, 112, and 179 ml/kg respectively. These values are much higher than the intake recommended by US EPA for infants under one year (US EPA, 1997). This study demonstrates the importance of considering water distribution intake in very young infants who may be particularly susceptible to water contaminants.

[Evaluation of the efficacy of the Toxoplasma gondii screening program among pregnant women in Nunavik, 1994-2003]. / Evaluation du Programme de dépistage de la toxoplasmose chez les femmes enceintes du Nunavik, 1994-2003.

OBJECTIVES: (1) To evaluate the efficacy of the Toxoplasma gondii screening program among Nunavik pregnant women in identifying seroconversions during pregnancy and performing an appropriate follow-up of the seroconverted women and their child; and (2) to evaluate the consequences of congenital Toxoplasma gondii infection. PARTICIPANTS: Women of child-bearing age and their children born between January 1994 and September 2003. SETTING: Nunavik. INTERVENTION: Potential cases of infection during pregnancy and of congenital toxoplasmosis were identified on the basis of serologic and hospitalization data. A medical chart revision was then performed. Descriptive statistics regarding the medical follow-up and treatment of suspected cases were compiled. OUTCOMES: 31 women who gave birth to 32 children were identified as potential cases. According to the medical charts, 19 women had a potential infection during pregnancy, the others were deemed to have been infected before conception. One woman had a definite infection. This woman and most of the 18 other potentially infected women and their children were treated appropriately. Because of missing data, it was impossible to determine with certainty the final status of two children. A diagnosis of congenital infection was rejected among the other children. CONCLUSION: Women with suspected infection and their children were generally well managed by the health care system. No clinical effect of congenital toxoplasmosis was noted during the studied period.

Seroprevalence of zoonoses in a Cree community (Canada).

Cree trappers and hunters are at risk for contracting infectious diseases conveyed by wildlife. We performed a study in a Cree community (Canada) to determine the seroprevalence of 8 zoonotic infections among hunters and trappers for evidence of exposure to Trichinella sp., Toxoplasma gondii, Toxocara canis, Echinococcus granulosus, Leptospira sp., Coxiella burnetii, Francisella tularensis, and Sin Nombre virus. A total of 50 participants (28 women and 22 men) were included in this study. Results indicate no or infrequent exposure to the Sin Nombre virus (0%) and 3 of the 4 parasites investigated (0-4%). Exposure to T. gondii (10%) and some bacteria appeared to be more prevalent (range, 4-18%). Overall, seropositivity was related to fishing, hunting, and trapping activities. Physicians should be aware of these infections in this population, particularly Q fever, tularemia, and leptospirosis.

Alterations of visual evoked potentials in preschool Inuit children exposed to methylmercury and polychlorinated biphenyls from a marine diet.

The aim of the present study was to assess the impact of chronic exposure to polychlorinated biphenyls (PCBs) and methylmercury on visual brain processing in Inuit children from Nunavik (Northern Québec, Canada). Concentrations of total mercury in blood and PCB 153 in plasma had been measured at birth and they were again measured at the time of testing in 102 preschool aged children. Relationships between contaminants and pattern-reversal visual evoked potentials (VEPs) were assessed by multivariate regression analyses, taking into account several potential confounding variables. The possible protective effects of selenium and omega-3 polyunsaturated fatty acids against methylmercury and PCB toxicity were also investigated. Results indicate that exposure to methylmercury and PCBs resulting from fish and sea mammal consumption were associated with alterations of VEP responses, especially for the latency of the N75 and of the P100 components. In contrast, the concomitant intake of omega-3 polyunsaturated fatty acids was associated with a shorter latency of the P100. However, no significant interactions between nutrients and contaminants were found, contradicting the notion that these nutrients could afford protection against environmental neurotoxicants. Interestingly, significant associations were found with concentrations of neurotoxicants in blood samples collected at the time of testing, i.e. at the preschool age. Our findings suggest that VEP can be used as a valuable tool to assess the developmental neurotoxicity of environmental contaminants in fish-eating populations.

Plasma organochlorine concentrations and bone ultrasound measurements: a cross-sectional study in peri-and postmenopausal Inuit women from Greenland.

BACKGROUND: Inuit women are highly exposed through their traditional seafood based diet to organochlorine compounds, some of them displaying endocrine disrupting properties. We hypothesized that this exposure might be related to bone characteristics that are altered in osteoporosis, because hormone deficiency is a known risk factor for the disease. METHODS: We measured quantitative ultrasound parameters (QUS) at the right calcaneum of 153 peri- and postmenopausal Inuit women (49-64 year old) from Nuuk, Greenland, and investigated the relation between these parameters and plasma organochlorine concentrations. We used high-resolution gas chromatography with electron capture detection to analyze plasma samples for 14 polychlorinated biphenyls (PCB) congeners and 11 chlorinated pesticides and metabolites. We analysed morning urine samples for cadmium, a potential confounder, by atomic absorption spectrometry. We used a validated questionnaire to document dietary and lifestyle habits as well as reproductive and medical histories. RESULTS: Concentrations of PCB 153, a surrogate of exposure to most organochlorines present in plasma samples, were inversely correlated to QUS parameters in univariate analyses (p < 0.001). However, PCB 153 concentrations were not associated with QUS values in multivariate analyses that comprised potential confounding factors such as age, body weight, former oral contraceptive use and current hormone replacement therapy (HRT) use, which were all significant predictors of bone stiffness (total R2 = 0.39; p < 0.001). CONCLUSION: Overall we found little evidence that organochlorines exposure is related to osteoporosis in Greenlandic Inuit women, but the hypothesis that exposure to dioxin-like compounds might be linked to decreased bone quality and osteoporosis deserves further attention.

Fatty acid composition of wild and farmed Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss).

The goal of this study was to examine the FA composition of wild and farmed Atlantic salmon (AS) and rainbow trout (RT). FA profiles were obtained by GC/FID. Results showed that lipid and n-3 highly unsaturated FA contents of farmed and wild AS were similar. Total n-3 and n-6 PUFA were significantly higher in farmed AS than in wild AS. Farmed RT contained more fat and less n-3 PUFA than wild RT. Our results show that farmed salmonids provide high levels of n-3 HUFA to consumers.

Total and specific immunoglobulin E and their relationship to respiratory symptoms in Quebéc children and adolescents.

BACKGROUND: Respiratory disease is a major cause of morbidity in young people. It is now recognized that atopy plays an important role in the development of chronic respiratory symptoms in children. OBJECTIVE: To examine the determinants and consequences of serum total and specific immunoglobulin E (IgE) in a general population sample of Québec children and adolescents. METHODS: In 1999, 2349 children and adolescents (nine, 13 or 16 years of age) who had participated in a respiratory symptom and disease questionnaire had their total IgE measured. Of these participants, a subsample of 451 children and adolescents was analyzed to detect antibodies to eight specific allergens (ie, allergens of dust mites [Dermatophagoides farinae and Dermatophagoides pteronyssinus], cat, dog, ragweed, Timothy grass, mould [alternaria] and cockroach). RESULTS: The geometric mean of the total IgE was 44.4 U/mL among all participants. Concentrations were higher in boys and increased with age. More than 41% of the participants were sensitized to at least one specific allergen. Such sensitization was strongly associated with the occurrence of respiratory conditions and symptoms, namely asthma, wheezing and rhinitis. Family history, school location and ethnic origin had an impact on the prevalence of atopy and total IgE levels. CONCLUSIONS: Allergic sensitization is a major determinant in the development of asthma, wheezing and rhinitis in children and adolescents in the province of Québec.

Cardiovascular disease risk factors and n-3 fatty acid status in the adult population of James Bay Cree.

BACKGROUND: Canadian native populations, which traditionally consume large amounts of fish, have lower rates of mortality from heart disease than do Canadian nonnative populations, which have low fish intakes. Fish oils rich in n-3 fatty acids may have a protective effect against cardiovascular disease (CVD) risk factors. OBJECTIVES: The purposes were to examine the profile of plasma phospholipid concentrations of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) among James Bay Cree and to verify the relation between these concentrations and CVD risk factors. DESIGN: The study population consisted of 917 subjects aged 18-74 y who participated in the 1991 Santé Québec Health Survey. Data were obtained through home interviews and clinic visits. Plasma samples were analyzed for phospholipid fatty acid composition. RESULTS: The mean fish consumption on the day before the survey was 60 g among the adult Cree population. Expressed as a percentage of total fatty acids, relative concentrations of EPA and DHA were 0.65% and 2.80%, respectively. n-3 Fatty acids were higher among coastal residents than among inland residents. A positive association was observed between plasma HDL and n-3 fatty acids. EPA and EPA+DHA were inversely associated with triacylglycerols. Among subjects aged 50-74 y, an inverse association between EPA and EPA:AA and total:HDL cholesterol was observed. CONCLUSIONS: n-3 Fatty acids may favorably influence some CVD risk factors. The Cree population must be encouraged to maintain their traditional fish-based diet, which may be one of the factors protecting them against mortality from CVD.

Cancer risk associated with household exposure to chloroform.

Chloroform (CHCl3) the trihalomethane most prevalent in drinking water, is a proven animal carcinogen and a suspected human carcinogen. Consequently, standards have been issued by health authorities to limit its concentration in drinking water. These limits are based solely on ingestion, without taking into account inhalation and skin contact. Exposure to CHCl3 was assessed for 18 men (age: mean 38 years; range 23-51) following a 10-min shower in their respective residences located in the Quebec City region (Canada). CHCl3 concentration was measured in alveolar air samples collected before, immediately after, and 15 min and 30 min following the shower. Indoor air and water concentrations were determined concomitantly. Mean CHCl3 concentrations in the air of the shower stall and in water were respectively 147 microg/m3 (SD = 56.2 microg/m3) and 20.1 microg/L (SD = 9.0 microg/L). Water concentrations were comparable to those documented in a large proportion of distribution networks in Canada. The mean increase in alveolar air CHCl3 concentration (deltaCHCIALV) at the end of the shower was 33 microg/m3 (SD = 14.7 microg/m3). A multiple-regression analysis revealed that deltaCHCl3ALV values were only associated with chloroform concentration in air of the shower stall. DeltaCHCl3ALV were described using a physiologically based pharmacokinetic (PBPK) model. This model was then used to estimate concentrations of CHCl3 metabolites bound to liver and kidney macromolecules following a shower, and also according to exposure scenarios that integrate drinking-water ingestion and air inhalation. The concentration predicted in the liver following a worst-case exposure scenario was 0.41 microg CHCl3 equivalents/kg of tissue, some 6,000 times lower than the lowest concentration that did not increase the incidence of hepatic tumors in laboratory animals. Data indicate that for this range of exposure the safety margin appears therefore considerable with respect to the potential carcinogenic effect of household exposure to CHCl3.

Fish consumption and blood lipids in three ethnic groups of Québec (Canada).

The purpose of this study was to compare fish intake and plasma phospholipid concentrations of n-3 fatty acids, in particular of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), among representative population samples of Québecers, James Bay Cree, and Inuit of Nunavik (Canada). The relationships between these concentrations and cardiovascular disease (CVD) risk factors were also investigated and compared in the three populations. In 1990-1992, the study subjects had participated in the extensive Santé Québec health surveys conducted in southern Québec, James Bay, and Nunavik. Significant differences in levels of CVD risk factors were found among these three populations. Globally, Inuit showed the lowest risk status for CVD compared with Cree and Québecers, despite the high prevalence of cigarette smoking and obesity. Daily fish intakes varied significantly among the three groups, averaging 13, 60, and 131 g for Québecers, Cree, and Inuit, respectively. Concentrations of EPA + DHA in plasma phospholipids were highest among Inuit (8.0%), second-highest among Cree (3.9%), and lowest among Québecers (1.8%). When the three populations were grouped together, there was a positive association between concentrations of EPA + DHA stratified into quartiles and HDL cholesterol, with a significant relation in quartile 4 (EPA + DHA > or = 4.04%). An inverse relation was also found between EPA + DHA and triacylglycerols in quartile 4. Our results indicate that increased consumption of fish as a source of n-3 fatty acids is beneficially associated with levels of HDL cholesterol and triacylglycerols.

Gestational age and birth weight in relation to n-3 fatty acids among Inuit (Canada).

Seafood consumption during pregnancy carries both benefits (high n-3 FA intake) and risks (exposure to environmental contaminants) for the developing fetus. We determined the impacts of marine n-3 FA and environmental contaminants on gestational age (GA) of Nunavik women and the anthropometric characteristics of their newborns. FA and contaminant (polychlorinated biphenyls and mercury) concentrations were measured in cord plasma of Nunavik newborns (n = 454) and compared with those of a group of newborns (n = 29) from southern Québec. Data were collected from hospital records and birth certificates. In Nunavik newborns, arachidonic acid (AA) was two times lower (P < 0.0001), whereas DHA concentration, the sigman-3 / sigman-6 ratio, and the percentage of n-3 highly unsaturated FA (HUFA) (of the total HUFA) were three times higher (P < 0.0001) compared with southern Québec newborns. After controlling for confounders, GA and birth weight were higher by 5.4 d [95% confidence interval (CI): 0.7-10.1] and 77 g (95% CI: -64 to 217) in the third tertile of percentage of n-3 HUFA (of the total HUFA) as compared with the first tertile. There was no evidence that contaminants had negative effects on GA or birth weight. In this seafood-eating population, an increase in the proportion of n-3 HUFA (of the total HUFA), measured in umbilical cord plasma phospholipids, was associated with a significantly longer GA.

Thyroid function of newborns and exposure to chlorine dioxide by-products.

In this study, the authors compared thyroid function of newborns from 11 municipalities where drinking water was disinfected by chlorine dioxide (ClO2) with that of newborns from 15 municipalities using chlorine disinfection. They estimated the mean neonatal blood thyroid stimulating hormone (TSH) levels and proportion of congenital hypothyroidism cases using the results of the Quebec neonatal screening for congenital hypothyroidism for 32,978 newborns over the period 1993-1999. There was no significant increase in the TSH level and no excess of congenital hypothyroidism when all newborns exposed to ClO2 were considered. However, for newborns with low birth weight, mean TSH level was significantly higher among those exposed to ClO2 than for those in the reference group.