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PubMed2000

Correlates of mental disorders in the Quebec general population of 6 to 14-year olds.

Previous epidemiological studies of correlates of child and adolescent mental disorders in the general population have focused more on child/adolescent and socioeconomic/sociodemographic characteristics than on family characteristics. Moreover, there are no generally accepted methods to analyze and interpret correlates. The purpose of the Quebec Child Mental Health Survey in this regard was twofold: (1) to identify correlates of DSM-III-R internalizing and externalizing disorders according to informant (youth, parent, teacher), for three age groups (6-8, 9-11, and 12-14 years), including relevant family characteristics not considered in previous studies; and (2) to interpret the relative importance of risk indicators by ranking correlates according to strength and consistency of association across age groups. Logistic regression models suggest the inconsistency of correlates across informants. The ranking of correlates reveals that individual and family characteristics make a more important contribution than do socioeconomic characteristics, thereby supporting the relevance of proximal variables in the development of psychopathology.

Adolescent↗
PubMed2003

Newborn urine screening programme in the province of Quebec: an update of 30 years' experience.

The introduction of our voluntary mass screening programme in 1971, in the province of Quebec, has permitted us to detect different inborn errors of metabolism in the newborn population using a thin-layer chromatographic (TLC) technique with sequential use of different sprays on the same plate. Abnormalities in amino acids and organic acids are detected in urine filter paper specimens of 21-day-old babies. Initial parental compliance is 90% and climbs to 99.25% for repeat sample requests. Screening is centralized in one laboratory, while diagnosis, counselling, management and follow-up are done in four regional centres. Over 25 inherited Mendelian disorders can be identified. There have been certain modifications in our programme throughout the years in order to increase efficiency, screen for a larger number of disorders, improve the quality of the collection of the urine filter paper samples, increase parental compliance and better manage the data bank. However, one goal has remained a priority: early prevention of genetic diseases. We present an overall view of our screening programme with an add-on technique to detect different organic acidurias, our recent statistics and the modifications implemented over the years.

Amino Acid Metabolism, Inborn Errors↗
PubMed2005

Familial resemblance in eating behaviors in men and women from the Quebec Family Study.

OBJECTIVE: It is commonly recognized that genetic, environmental, behavioral, and social factors are involved in the development of obesity. The family environment may play a key role in shaping children's eating behaviors. The purpose of this study was to estimate the degree of familial resemblance in eating behavioral traits (cognitive dietary restraint, disinhibition, and susceptibility to hunger). RESEARCH METHODS AND PROCEDURES: Eating behavioral traits were assessed with the Three-Factor Eating Questionnaire in 282 men and 402 women (202 families) from the Quebec Family Study. Familial resemblance for each trait (adjusted for age, sex, and BMI) was investigated using a familial correlation model. RESULTS: The pattern of familial correlation showed significant spouse correlation for the three eating behavior phenotypes, as well as significant parent-offspring and sibling correlations for disinhibition and susceptibility to hunger. According to the most parsimonious model, generalized heritability estimates (including genetic and shared familial environmental effects) reached 6%, 18%, and 28% for cognitive dietary restraint, disinhibition, and susceptibility to hunger, respectively. DISCUSSION: These results suggest that there is a significant familial component to eating behavioral traits but that the additive genetic component appears to be small, with generalized heritability estimates ranging from 6% to 28%. Thus, non-familial environmental factors and gene-gene and gene-environmental interactions seem to be the major determinants of the eating/behavioral traits.

Adolescent↗
PubMed2006

Ethnic differences in body composition and other markers of cardiovascular disease risk: study in matched Haitian and White subjects from Quebec.

OBJECTIVES: People of African descent may be at greater risk of metabolic syndrome (MS) compared with whites. We examined the associations among MS markers, body composition, and resting metabolic rate (RMR) in black Haitians and in white subjects living in Quebec, Canada. RESEARCH METHODS AND PROCEDURES: Forty randomly selected Haitians were matched with 40 white subjects for age, sex, and BMI. Glycemic status and insulin resistance were assessed based on a 3-hour glucose tolerance test. Blood lipids, blood pressure, abdominal fat (computed tomography), and waist circumference (WC) were measured. RMR was estimated by indirect calorimetry. RESULTS: Triglycerides were significantly correlated with blood pressure only in Haitians and with the area under the curve for insulin only in whites. Haitians had significantly (p < 0.05) lower triglycerides and higher high-density lipoprotein-cholesterol concentrations but higher blood pressure than whites at any given WC value. General linear models showed that Haitians had less visceral adipose tissue than whites for the same WC. RMR was lower among Haitians for any given value of BMI or WC than in whites. Also, WC was more strongly associated with glucose area under the curve and to log-homeostasis model assessment in white than in Haitian subjects. DISCUSSION: The MS may be ethnospecific in its features and etiology. The standard anthropometric indices of obesity may not be as effective in populations of African descent compared with whites, unless appropriate cut-off values are defined.

Adult↗
PubMed2004

Insulin resistance syndrome in a representative sample of children and adolescents from Quebec, Canada.

OBJECTIVES: To estimate the prevalence of insulin resistance syndrome (IRS) in a representative sample of youth. To test for the independent contribution of insulin resistance (IR) and adiposity to clustering of metabolic risk factors. To identify the underlying components of IRS. To examine the relationship between adiposity and fasting plasma levels of free fatty acids (FFA). METHODS: In 1999, we conducted a school-based survey of a representative sample of youth aged 9, 13 and 16 y in Quebec, Canada. Age-specific questionnaire data, standardized clinical measurements and a fasting blood sample were available for 2244 subjects. Fasting insulin and HOMA were used as surrogate measures of IR. RESULTS: In all age-sex groups, adiposity indices, blood pressure (BP), plasma glucose and triglycerides (TG) increased significantly with increasing insulin quartiles while HDL cholesterol (HDL-C) decreased. The overall prevalence of IRS defined as hyperinsulinaemia combined with two or more risk factors including overweight, high systolic BP, impaired fasting glucose, high TG and low HDL-C, was 11.5% (95% CI: 10.2-12.9). There were no significant differences in the prevalence of IRS across ages or between sexes. The independent contribution of adiposity to clustering of risk factors was stronger than that of fasting insulin (or HOMA-IR). Factor analysis revealed three factors (BMI/insulin/lipids, BMI/insulin/glucose and diastolic/systolic BP) consistent across ages suggesting that more than one pathophysiologic process underlies IRS. Although elevation of FFA might be in the causal pathway linking obesity to IR, we did not detect any consistent association between measures of fatness and fasting plasma FFA. CONCLUSION: IRS is highly prevalent in youth, even among children as young as age 9 y. Factor analysis identifies three physiologic domains within IRS with a unifying role for markers of IR and adiposity.

Adolescent↗
PubMedDate not supplied

Sources of nitrate exposure in residents of rural areas in Quebec, Canada.

Nitrate exposure was investigated in a group of 187 people using well water and living in four areas of rural Quebec (Canada) with intensive agricultural activities. Nitrate intake was evaluated using a 24-h dietary recall and a food frequency questionnaire, in conjunction with a validated food database and measurements of nitrate concentrations in private wells. The total internal dose was estimated by means of the 24-h urinary nitrate excretion, while taking into account risk factors for endogenous nitrate formation. Mean (geometric) 24-h urinary nitrate excretion was 16.9 mg N for the 100 people with low groundwater contamination (mean nitrate concentration=0.18 mg N/l) and 23.3 mg N in the 87 individuals with moderate groundwater contamination (mean nitrate concentration=7.1 mg N/l). A multivariate analysis revealed that dietary nitrate intake during the last 24 h was the principal source of exposure, followed by water intake during the last 24 h. The Quetelet index was also a significant predictor of urinary excretion. The total predictive model explained only 29% of the variability in urinary nitrate excretion (R2=0.286). Neither the inflammatory status as indicated by elevated C reactive protein, the presence of Helicobacter pylori antibodies nor the occurrence of diarrhea during the last 24 h prior to urine collection were associated with urinary nitrate excretion. In conclusion, food and to a lesser extent water contribute to nitrate exposure in this rural setting with moderate water contamination. Better predictors of endogenous nitrate production are needed to improve our ability to model nitrate body burden and estimate associated health risks.

Adult↗
PubMed2005

Shared and specific susceptibility loci for schizophrenia and bipolar disorder: a dense genome scan in Eastern Quebec families.

The goal of this study was to identify susceptibility loci shared by schizophrenia (SZ) and bipolar disorder (BP), or specific to each. To this end, we performed a dense genome scan in a first sample of 21 multigenerational families of Eastern Quebec affected by SZ, BP or both (N=480 family members). This probably constitutes the first genome scan of SZ and BP that used the same ascertainment, statistical and molecular methods for the concurrent study of the two disorders. We genotyped 607 microsatellite markers of which 350 were spaced by 10 cM and 257 others were follow-up markers in positive regions at the 10 cM scan. Lander and Kruglyak thresholds were conservatively adjusted for multiple testings. We maximized the lod scores (mod score) over eight combinations (2 phenotype severity levels x 2 models of transmission x 2 analyses, affected/unaffected vs affected-only). We observed five genomewide significant linkages with mod score >4.0: three for BP (15q11.1, 16p12.3, 18q12-q21) and two for the shared phenotype, that is, the common locus (CL) phenotype (15q26,18q12-q21). Nine mod scores exceeded the suggestive threshold of 2.6: three for BP (3q21, 10p13, 12q23), three for SZ (6p22, 13q13, 18q21) and three for the CL phenotype (2q12.3, 13q14, 16p13). Mod scores >1.9 might represent confirmatory linkages of formerly reported genomewide significant findings such as our finding in 6p22.3 for SZ. Several regions appeared to be shared by SZ and BP. One linkage signal (15q26) appeared novel, whereas others overlapped formerly reported susceptibility regions. Despite the methodological limitations we raised, our data support the following trends: (i) results from several genome scans of SZ and BP in different populations tend to converge in specific genomic regions and (ii) some of these susceptibility regions may be shared by SZ and BP, whereas others may be specific to each. The present results support the relevance of investigating concurrently SZ and BP within the same study and have implications for the modelling of genetic effects.

Adult↗
PubMed1999

The association of birth interval, maternal age and season of birth with the fertility of daughters: a retrospective cohort study based on family reconstitutions from nineteenth and early twentieth century Quebec.

In a historical follow-up study, we evaluated the association of the fertility of daughters with five perinatal factors: short (< 15 months) or long (> or = 45 months) preceding birth interval, low (< or = 20 years) or advanced (> or = 40 years) maternal age and season of birth. We used data concerning 2062 women married before the age of 31 and born in the Saguenay region of Quebec, Canada, between 1850 and 1899. Time between the wedding and first birth was used for the estimation of differences in fertility. Using logistic regression and controlling for several potential confounders, we found a slightly increased risk of monthly failure of conception for daughters born after a short but not for those born after a long birth interval (odds ratios [ORs] 1.09 [0.89, 1.33] and 0.87 [0.65, 1.16], respectively, with intervals between 21 and 32 months as the reference category). A slightly increased risk of conceptive failure was also seen for daughters of younger and older mothers (ORs 1.08 [0.89, 1.30] and 1.11 [0.91, 1.35], respectively, compared with maternal age between 24 and 30 years as the reference category). Fertility varied by season of birth (P = 0.02), with summer-born daughters having lowest and winter-born daughters having highest fertility. These results are consistent with the idea that maternal factors before or around birth play a role in the aetiology of reduced fertility. The data, however, do not unequivocally support the hypothesis that gave rise to the present study, namely that ovarian development may be disturbed after conception in conditions with an increased risk of maternal menstrual cycle irregularities.

Adolescent↗
PubMed2003

[Public health: the control of meningococcal disease in Quebec].

A first outbreak of serogroup C meningococcal disease occurred in the province of Quebec in 1990-1992 and lead to a mass immunization campaign using polysaccharide vaccines. In 2001, a second outbreak was identified and a mass vaccination campaign was carried out, using the newly licensed conjugate vaccine. Clinical, epidemiological, economic and social studies were instrumental in the decision making for implementing these control programs.

Disease Outbreaks↗
PubMed2003

[Genetics of obesity and metabolic complications in the Quebec Family Study].

Considerable progress has been accomplished over the past 10 years in the understanding of the genetic basis of obesity and its related metabolic complications. It is now well established that obesity aggregates within families and that genes are partly responsible for this familial aggregation. The number of genes potentially involved in obesity continues to grow. This review summarizes the evidence accumulated so for regarding the contribution of genetic factors in obesity and the number of gene and loci linked to obesity in the Quebec Family Study.

Cohort Studies↗
PubMed2001

Interactions among the glucocorticoid receptor, lipoprotein lipase, and adrenergic receptor genes and plasma insulin and lipid levels in the Quebec Family Study.

The aim of the study was to investigate the possible interactions among the glucocorticoid receptor (GRL), lipoprotein lipase (LPL), and adrenergic receptor (ADR) genes on plasma insulin and lipid levels. The study was cross-sectional and based on 742 individuals from phase 2 of the Quebec Family Study (QFS) cohort. Gene markers were identified by Southern blot analysis or polymerase chain reaction (PCR). Plasma glucose and insulin in the fasted state and during an oral glucose tolerance test (OGTT) were determined and insulin and glucose areas were computed. Triglyceride (TG) and cholesterol concentrations in plasma and lipoprotein fractions were determined enzymatically. The results show that GRL and LPL variants had independent effects on plasma high-density lipoprotein cholesterol (HDL-C) and two beta2-ADR variants were related to total cholesterol concentrations. The alpha2-ADR gene Dral polymorphism was the only variant that had an independent effect on the plasma insulin area. Gene-gene interaction effects were found between GRL and alpha2-ADR genes for low-density lipoprotein cholesterol ([LDL-C] P = .013) and between GRL and LPL genes for HDL-C (P = .045). Higher-order interaction effects involving GRL, LPL, and ADR markers were observed for the plasma insulin area (P = .001 to .025) but not the glucose area. After correction for multiple tests, the findings remained essentially unchanged for the insulin area but became nonsignificant for the lipid phenotypes. In conclusion, multiple interactions among GRL, LPL, and ADR gene markers contribute to insulin metabolism and perhaps to lipid levels, while no significant effect is found for each gene separately. The LPL locus appears to determine the pattern of interactions with ADR and GRL loci. These results suggest that gene-gene interaction effects could play a role in the etiology of risk factors for common chronic diseases.

Area Under Curve↗
PubMedDate not supplied

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.

Adolescent↗
PubMed2004

Exposure of a Cree population living near mine tailings in northern Quebec (Canada) to metals and metalloids.

The authors investigated the effect of residues from copper- and gold-mining on the Cree population of Oujé-Bougoumou, located 560 km north of Quebec City, Canada. Subjects (225) from Oujé-Bougoumou and a control population (100) completed a questionnaire on lifestyle and dietary habits and provided blood and urine samples for analysis. Geometric means of arsenic, lead, cadmium, and copper concentrations were not significantly different for subjects or controls 15 yr and older or children (8-14 yr old). However, blood zinc was higher and selenium was lower in Oujé-Bougoumou samples. Mean blood lead level was higher in children from Oujé-Bougoumou, but lower in adults aged 40 yr and older. For adults (15 yr and older) blood lead level increased with age and was higher in men, those who hunted, and consumed wild meat (R2 = 0.43). Blood cadmium increased with age and smoking (R2 = 0.61). No influence of mine residues was observed among residents of Oujé-Bougoumou, but lifestyle exposure associations were noted for both communities.

Adolescent↗
PubMedDate not supplied

Mesothelioma and asbestos in the Province of Quebec, 1969-1972.

All records of patients who died of mesothelioma in the Province of Quebec during the period 1969-1972 were collected and reviewed. Asbestos exposure in this group was compared with that in two control groups, one of persons dying of accidental causes and the other of those dying of cardiovascular disease. The mortality rate for mesothelioma was estimated at between 2.3 and 2.8 per million per year. Men were affected twice as frequently as women, this difference being related exclusively to pleural mesothelioma. The incidence in urban regions was much higher than in rural areas, and areas involved in mining showed an incidence in the expected range. Thirty-four percent of the patients with mesothelioma and only 2% of controls had histories of direct exposure to asbestos. This exposure was related to asbestos processing and not its production. No woman gave a history of occupational exposure to asbestos. It appeared that chrysotile may be less related to the production of mesothelioma than other types of asbestos fibers.

Asbestos↗
PubMedDate not supplied

Temporal patterns of exposure and nonmalignant pulmonary abnormality in Quebec chrysotile workers.

Questionnaire, radiographic, and lung function information for 983 Quebec chrysotile workers at work in 1966 was used to develop five clinical response scales (i.e., parenchymal and pleural fibrosis, airflow limitation, chronic bronchitis, and airway reactivity). The relationship of the scales to variables describing temporal patterns of exposure was studied, taking into account cumulative exposure, age, and smoking. All response scales related to variables containing only time information, and in all cases temporal patterns of exposure influenced exposure response relationships. For pulmonary fibrosis, the strongest relationships were to cumulative exposure; for pleural fibrosis to exposure peaks and residence time of dust in the lung; for airway reactivity to early and recent exposure; and for airflow limitation and chronic bronchitis to smoking and to dust level and load over time. These results add to the gathering evidence that exposures to environments containing airborne asbestos may result in airway abnormalities.

Adult↗
PubMedDate not supplied

Dioxin-like compounds in fishing people from the Lower North Shore of the St. Lawrence River, Quebec, Canada.

In this study, investigators assessed exposure to dioxin-like compounds in a fishing population that inhabits small coastal communities along the Lower North Shore of the St. Lawrence River, Quebec. This population relies heavily on wildlife foods for sustenance. Investigators analyzed chemically the most popular marine foods (i.e., fish, crustaceans, sea mammals, and sea-bird eggs), and they also obtained 25 human plasma samples from individuals in two villages along the river. The mean level of total polychlorinated biphenyls in this population was approximately twice that found in the entire fishing cohort. Plasma levels of dioxin-like compounds, expressed as tetrachlorodibenzodioxin toxic equivalents, were approximately eight times higher than levels in urban residents. Most of the increase in tetrachlorodibenzodioxin toxic equivalents in the selected fish eaters resulted primarily from an elevation in polychlorinated biphenyls. Concentrations of dioxin-like compounds from the Lower North Shore were low in fish and seals, but concentrations were elevated in the eggs of sea birds. Given that there was also a significant statistical correlation in the entire population between human plasma levels and consumption of birds' eggs-and not other traditional foods-much of the increased human dose appeared to originate from this one food source. Because there appear to be increased, but uncertain, health risks from this elevated body burden, investigators advised the residents of the area to avoid consumption of wild birds' eggs (i.e., a food source of minor nutritional importance).

Adult↗
PubMedDate not supplied

Risks of developing cancer relative to living near a municipal solid waste landfill site in Montreal, Quebec, Canada.

In this study, we sought to determine whether men who lived near the Miron Quarry municipal solid waste landfill site in Montreal, Quebec, Canada, were at higher risk for developing cancer than individuals who lived at more remote locations. Subjects were selected from a previously completed population-based, interview, cancer case-control study of men who lived in metropolitan Montreal. Thirteen sites of cancer (n = 2 928 subjects) and a population-based control group (n = 417) were analyzed. We used the exact street address at the time of diagnosis to classify subjects by geographic zones and distance from the site. We used unconditional logistic regression to estimate odds ratios (ORs) and associated 95% confidence intervals (CIs) for each site of cancer, adjusted for key covariates. In the exposure zone nearest to the site, elevated risks were found for cancers of the pancreas (adjusted OR = 1.4 [95% CI = 0.8, 2.6]); liver (OR = 1.8 [95% CI = 0.8, 4.3]); and prostate (OR = 1.5 [95% CI = 1.0, 2.1]). A high risk was also found for pancreatic cancer (OR = 1.7 [95% CI = 0.9, 3.5]) and the non-Hodgkin's lymphomas (OR = 1.5 [95% CI = 0.8, 2.6]) in a subexposure zone approximately downwind from the site. We used distance from the site as another exposure metric, and higher-than-expected risks were found for pancreatic cancer (OR for living within 1.25 km of the site [OR<1.25km] = 2.2 [95% CI = 1.0, 4.6]); liver cancer (OR<1.5km = 2.1 [95% CI = 0.8, 5.3]); kidney cancer (OR<2 km = 1.4 [95% CI = 0.9, 2.3]); and the non-Hodgkin's lymphomas (OR<1km = 2.0 [95% CI = 1.0, 4.0]). Data from this study and from a previous investigation at the same site suggest that men who lived near this landfill site may have been-and may continue to be-at excess risk of cancers of the liver, kidney, pancreas, and non-Hodgkin's lymphomas.

Adult↗
PubMedDate not supplied

Autosomal recessive disorders in Saguenay-Lac-Saint-Jean (Quebec, Canada): estimation of inbreeding from isonymy.

The total inbreeding coefficient of a group of 574 individuals with autosomal recessive disorders (ARD) from Saguenay-Lac-Saint-Jean, a geographically isolated region of northeastern Quebec, was estimated from isonymy and compared to the mean inbreeding coefficient calculated from the genealogies. Its value was compared to that of 1722 matched controls. The total inbreeding coefficient was similar in both ARD and control groups, but higher than the values calculated from the genealogies. Most of the increase was due to the random component of inbreeding. This isonymy study confirmed that the high frequency of ARD in Saguenay-Lac-Saint-Jean is mainly the result of founder effect and genetic drift.

Case-Control Studies↗