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PubMed1994

Retrospective cohort study of workers of a synthetic textiles plant in Quebec: I. General mortality.

This paper presents results from a retrospective cohort study of workers of a synthetic textiles plant in Quebec. This plant has been the subject of a previous case-control study, in which an excess risk of colorectal cancer was observed. The cohort consisted of 7,487 men and 2,724 women who had worked at least 1 year at the plant and who were either working in 1947 or were newly employed between 1947 and 1977. The period of follow-up was from 1947 to 1986, thus yielding 307,278 person-years of observation. Mortality rates for most causes of death were less than expected; the standardized mortality ratio (SMR) for all causes of death among men was 0.73 (95% confidence interval (CI): 0.70-0.77) and among women it was 0.77 (95% CI: 0.68-0.87). For men, the SMR for all neoplasms was 0.76 (95% CI: 0.69-0.83) and for colorectal cancer it was 0.69 (95% CI: 0.52-0.92). For women, the SMR for all neoplasms was 1.01 (95% CI: 0.83-1.22) and for colorectal cancer it was 1.02 (95% CI: 0.57-1.69). Among men, risks for ischemic heart disease increased with increasing length of service at the plant, even though the SMRs were less than unity (overall SMR = 0.76; 95% CI: 0.70-0.83); no trend was observed for women. SMRs and relative risks were also calculated according to duration of employment in each processing unit. Of the scores of associations tested, very few showed increased risks. Of those showing increased risks, the data were not persuasive in indicating a connection with work at the plant; nevertheless, some of these associations may be worth following up in future studies. The following associations of potential significance were observed: all cancers, liver and gallbladder cancers, non-Hodgkin's lymphomas, and reticulum cell sarcoma in the cellulose acetate fiber manufacturing unit; all cancers in the polypropylene and cellulose triacetate extrusion unit and in the janitor unit; leukemias in the unexposed unit; ischemic heart disease in the maintenance and janitor units; and cerebrovascular disease in the weaving unit.

Adult↗
PubMed1995

Perimenstrual symptoms and working conditions among hospital workers in Quebec.

Perimenstrual symptoms are among the most common disorders of women. Seven perimenstrual symptoms were related to working conditions among 539 hospital workers in a retrospective cohort questionnaire study, as part of a larger examination of health problems and working conditions of Quebec hospital workers. Only 8% of women had experienced no symptoms of discomfort associated with their last menstrual period. Lower abdominal pain, the most common symptom (58% prevalence), was associated with lifting weights (usually patients) in a logistic regression adjusted for parity and contraceptive use. Back pain, leg pain, swelling, and headache were associated with indicators of time pressure and fast work speed. Back pain during menstruation was experienced by 44% of workers. Studies of the prevalence and etiology of back pain, a common occupational health problem among hospital workers, may be confused if perimenstrual back pain is not taken into account. Similar reservations hold for the results on other perimenstrual symptoms that are also likely to occur outside the perimenstrual period, such as leg pain, irritability, and headache.

Adult↗
PubMed1984

Neural tube defects in Eastern Ontario and Western Quebec: demography and family data.

This paper reports the results of a study of families in the Eastern Ontario/Western Quebec region who had a child born with a neural tube defect during the years 1969-1981. As in several other geographic areas, the prevalence of neural tube defects at birth has fallen from previous levels. However, there was no evidence of further decline during the period of study. Socioeconomic and ethnic influences were noted, but there was no evidence of seasonal variation or any correlation with maternal age or parity. There was support for a causative role of maternal fever in some cases. The rates of miscarriage varied between pregnancies before and those after the proband, and there was an excess of males born prior to the proband. Family studies showed a 2.4% risk for sibs born after the proband and an excess of affected relatives on the maternal side. Knowledge of rates of occurrence in relatives is useful for counseling and the interpretation of the results of alpha-fetoprotein screening.

Abortion, Spontaneous↗
PubMed1995

Linkage results on 11Q21-22 in Eastern Quebec pedigrees densely affected by schizophrenia.

The 11q21-22 region is of interest for schizophrenia because several candidate genes are located in this section of the genome. The 11q21-22 region, including DRD2, was surveyed by linkage analysis in a sample (N = 242) made of four large multigenerational pedigrees densely affected by schizophrenia (SZ) and eight others by bipolar disorder (BP). These pedigrees were ascertained in a large area of Eastern Quebec and Northern New Brunswick and are still being extended. Family members were administered a "consensus best-estimate diagnosis procedure" (DSM-III-R criteria) blind to probands and relatives' diagnosis and to pedigree assignment (SZ or BP). For linkage analysis, 11 microsatellite polymorphism (CA repeat) markers, located at 11q21-22, and comprising DRD2, were genotyped. Results show no evidence of a major gene for schizophrenia. However, a maximum lod score of 3.41 at the D11S35 locus was observed in an affected-only analysis of one large SZ family, pedigree 255. Whether or not the positive linkage trend in pedigree 255 reflects a true linkage for a small proportion of SZ needs to be confirmed through the extension of this kindred and through replication.

Base Sequence↗
PubMed2003

Genetic heterogeneity in a very large bipolar affective disorder pedigree from Quebec.

We previously reported a genome-wide scan for bipolar affective disorder based on a multigenerational family sampled from a relatively homogeneous population derived from founding families that migrated to an isolated area of Quebec from the early 1830s onwards. For the genome scan, the pedigree was split into five branches to facilitate calculation and a second family was added to more specifically analyze chromosome 12 results. In the present study, we reanalyzed the undivided pedigree after genealogical links were reconstructed over ten generations to investigate a founder effect using an algorithm in the SIMWALK2 package. Our results do not lend support to the presence of a common haplotype shared among affected individuals.

Algorithms↗
PubMed1988

Encephalitis among Cree children in northern Quebec.

We report a neurological disease among Cree Indian children in a northern Quebec village. The disease manifests as severe mental retardation, cerebral atrophy with white matter changes and calcifications, and systemic immunological abnormalities. Eleven cases are known in five families. The familial incidence of cases and the high degree of parental consanguinity suggest a genetic contribution. We propose that this entity may be caused by an unusual viral infection in a genetically vulnerable host.

Adolescent↗
PubMed1988

Leukoencephalopathy among native Indian infants in northern Quebec and Manitoba.

We report 14 cases of a severe familial leukoencephalopathy among native North American Indian infants in northern Quebec and Manitoba. Affected infants have hypotonia and mild motor delay, followed by seizures, hypotonia or spasticity, eye deviation, and abnormal posture during a febrile illness around 6 months of age. Death follows a rigid, vegetative state that manifests days to months after disease onset and is marked in some cases by prominent autonomic disturbances, blindness, and cessation of head growth. Symmetrical hemispheric white matter lucencies and diffuse hypomyelination of the cerebral hemispheres and brainstem are the radiological and pathological hallmarks. This disease differs from the known diseases of cerebral myelin. An autosomal recessive pattern of inheritance awaits statistical confirmation. The proposed cause is a delay in development or abnormal turnover of central nervous system myelin.

Brain↗
PubMed1981

Familial articular chondrocalcinosis in Quebec.

The existence of articular chondrocalcinosis was documented in 9 members of 3 generations of a Quebec family. No associated or secondary forms of the disease were found. The clinical manifestations appeared early in life, and extensive radiologic involvement was apparent. We determined that genetic transmission was dominant, either autosomal or sex-linked, and not related to the HLA system.

Chondrocalcinosis↗
PubMed2003

Heritability of LDL peak particle diameter in the Quebec Family Study.

LDL size has been associated with the risk of coronary heart disease. The objective of the present study was to verify whether familial factors influence LDL peak particle diameter (LDL-PPD), a quantitative trait reflecting the size of the major LDL subclass. LDL-PPD was measured by 2-16% polyacrylamide gradient gel electrophoresis in 681 members of 236 nuclear families participating in the Quebec Family Study. LDL-PPD was adjusted for age (LDL-PPD1), age and body mass index (LDL-PPD2), or age, body mass index, and plasma triglyceride levels (LDL-PPD3) separately in men and women. The residual scores were used to test for familial aggregation, using an ANOVA and to compute maximum likelihood estimates of familial correlations. The ANOVA test revealed that family lines accounted for 47.4%, 46.7%, and 48.9% of the variance in the LDL-PPD1, LDL-PPD2, and LDL-PPD3 phenotypes, respectively. The pattern of familial correlations revealed no significant spouse correlations but significant parent-offspring and sibling correlations for the three LDL-PPD phenotypes, with maximal heritability estimates of 59%, 58%, and 52% for LDL-PPD1, LDL-PPD2, and LDL-PPD3, respectively. These results suggest that LDL-PPD strongly aggregates in families, and that the familial resemblance appears to be primarily attributable to genetic factors. Genes responsible for this genetic contribution remain to be identified.

Adult↗
PubMed2006

Revisiting physicians' financial incentives in Quebec: a panel system approach.

Do Primary Care Physicians (PCPs) react strategically to financial incentives and if so how? To address this question, we follow a quasi-natural experiment in Quebec, using a panel system technique. In so doing, we both correct for underestimation biases in earlier time series findings and generate new results on the issue of complementarity/substitution between consultations with varying levels of technicality. Under both techniques, we show that PCPs are sensitive to the enforcement and subsequent temporary removals of expenditure caps and more generally, to changes in consultations' relative prices over time. These results support the existence of a discretionary power over the choice of consultation, PCPs increasing strategically the number of the more technical (and therefore more lucrative) consultations when pressed to defend their income. This finding for primary care parallels the now well-established DRG creep in hospitals. The panel system approach offers a better account of the complexity surrounding PCPs' decision-making process. In particular, it successfully addresses issues of physician heterogeneity, jointness between consultations and temporal breaks and generates robust estimates of PCPs volume and quality reactions to regulatory changes.

Budgets↗
PubMed2006

Cancer incidence in a cohort of Ontario and Quebec women having bilateral breast augmentation.

The possibility that women, who receive breast implants for cosmetic purposes, have increased long-term risks of developing cancer continues to be debated. The objective of our study was to prospectively examine cancer incidence among women who received breast implants. A cohort was assembled of 24,558 women, 18 years of age and older, who underwent bilateral cosmetic breast augmentation, and 15,893 women who underwent other cosmetic procedures in Ontario or Quebec between 1974 and 1989. These plastic surgery patients were selected from the same clinics as the implant population. Incident cancers were identified by linking to Canadian registry data up to December 31, 1997. In total, 676 cancers were identified among women who received breast implants compared to 899 expected based on general population rates (standardized incidence ratio (SIR) = 0.75; 95% confidence interval (CI) = 0.70-0.81). Overall cancer incidence rates among women who received breast implants were similar to that of the other plastic surgery patients (relative risk (RR) = 0.91, 95% CI = 0.81-1.02). However, women who received breast implants had lower breast cancer rates than the plastic surgery patients (RR = 0.64, 95% CI = 0.53-0.79). No increased risks were observed among the implant population for any of the other cancer sites examined. Comparisons involving only women who received breast implants found no association between long-term breast cancer incidence and implant site (submuscular vs. subglandular), fill (saline vs. silicone) or envelope (polyurethane-coated or not). In conclusion, women undergoing cosmetic breast augmentation do not appear to be at an increased long-term risk of developing cancer.

Adolescent↗
PubMed2004

Screening decreases prostate cancer mortality: 11-year follow-up of the 1988 Quebec prospective randomized controlled trial.

PURPOSE: This clinical trial is aimed at evaluating the impact of prostate cancer screening on cancer-specific mortality. SUBJECTS AND METHODS: Forty-six thousand four hundred and eighty-six (46,486) men aged 45-80 years registered in the electoral roll of the Quebec city area were randomized in 1988 between screening and no screening. Screening included measurement of serum prostatic specific antigen (PSA) using 3.0 ng/ml as upper limit of normal and digital rectal examination (DRE) at first visit. At follow-up visits, serum PSA only was used. RESULTS: Seventy-four (74) deaths from prostate cancer occurred in the 14,231 unscreened controls while 10 deaths were observed in the screened group of 7,348 men during the first 11 years following randomization. Median follow-up of screened men was 7.93 years. A Cox proportional hazards model of the age at death from prostate cancer shows a 62% reduction (P < 0.002, Fisher's exact test) of cause-specific mortality in the screened men (P = 0.005). These results are in agreement with the continuous decrease of prostate cancer mortality observed in North America.

Aged↗
PubMed2002

Molluscan shellfish biomarker study of the Quebec, Canada, Saguenay Fjord with the soft-shell clam, Mya arenaria.

A spatial and temporal survey of six sites in the Saguenay Fjord and of one adjacent site in the St. Lawrence River estuary (Quebec, Canada) was undertaken to study the possible effects of anthropogenic contaminant input on soft-shell clam (Mya arenaria) populations. Bivalve sampling sites were selected because they reflected a range of areas representative of either no known (or apparent) pollution sources or of areas potentially influenced by different gradients and types of contamination sources. The most upstream site selected in the Saguenay Fjord, nearest to a highly populated and industrialized sector, and the most downstream site, near its mouth with the St. Lawrence River estuary, spanned a distance of some 70 km and encompassed the entire intertidal area suitable for Mya arenaria habitat. To measure effects in collected animals, we used a comprehensive battery of biomarkers composed of metallothionein-like proteins (MT), 7-ethoxyresorufin O-deethylase activity (EROD), DNA damage (DD), lipid peroxidation (LPO), vitellinlike proteins (Vn), phagocytosis (PHAG), nonspecific esterase (NspE) activity, and condition factor (weight-to-length ratio of clams). Vn, PHAG, DD, and NspE biomarkers were assayed in hemolymph (or hemocytes), whereas others (MT, EROD, LPO) were determined in the digestive gland. Whole-tissue metal content was also quantified in clams collected in the spatial survey. The spatial survey conducted in June 1997 showed significant effects at all sites, and principal component analysis indicated in addition that the more important responses were linked to the MT, LPO, and NspE biomarkers. Clams collected from sites closest to the upstream reaches of the fjord generally displayed higher levels of tissue metals (cadmium, manganese), as well as greater responses of NspE activity, MT, LPO, and PHAG. Animals collected from sites influenced by municipal wastewaters had higher levels of Vn, suggesting the presence of environmental estrogens. The results of the temporal survey (six monthly samplings of clams at three sites from May through October, 1997) showed that the bivalve reproductive cycle (vitellogenesis and spawning) can modulate the expression of several biomarkers. Vn levels, for example, were positively correlated with DD and EROD and negatively correlated with MT, suggesting that reproduction can influence the susceptibility of clams to some contaminants. Discrimination analysis over the 6 months of sampling revealed that the mean value of the discriminant function changed significantly over time, suggesting important changes in the relative contribution of each biomarker. In short, this study has provided evidence that clam populations in the Saguenay Fjord are impacted by multiple sources of contamination whose effects can be modulated by reproduction.

Animals↗
PubMedDate not supplied

A cohort approach to tobacco use and mortality: the case of Quebec.

BACKGROUND: Cigarette smoking is the No. 1 cause of premature death among Canadians. However, tobacco consumption dropped by 35% in Canada during the 1980s. METHODS: Using data collected during a Quebec health survey, we evaluated the prevalences of tobacco use by birth cohort. Since mortality has been decreasing for both sexes, we computed gender-specific cohort mortality indices for tobacco-related causes of death. In the analysis, we took into account the inevitable time lag between adopting the behavior and becoming the victim of a smoking-attributable disease. RESULTS: Results indicate a systematic decrease in tobacco use from older male cohorts to younger ones across all ages; however, for females an increase in tobacco use has been observed from one cohort to the next but there seems to be hope for a future trend toward breaking the habit. While a decline in tobacco-related mortality has been observed among men (e.g., death from ischemic heart disease), female lung cancer mortality increased considerably. Finally, we present an indicator measuring the years of potential life lost for some tobacco-related causes of death. CONCLUSIONS: The cohort approach allows us to observe birth-cohort-specific trends, thereby more easily relating past behavior to current mortality levels. In terms of prevention, increasing female mortality from lung cancer should become a major concern and a motivator in the fight against tobacco use.

Adult↗
PubMed2002

Pregnancy planning and folic acid supplement use: results from a survey in Quebec.

BACKGROUND: To decrease the risk of neural tube defects, all women planning pregnancy or capable of becoming pregnant should take folic acid supplements. The aim of the study was to describe the association between pregnancy planning and vitamin supplement use. METHODS: A total of 1,858 pregnant women registered for a prenatal ultrasound examination in the Montérégie region, Province of Quebec, Canada, completed a questionnaire between November 1997 and May 1998. Pregnancy planning was described by six ordinal variables, which were included in a nonlinear principal component analysis. The main dimension representing the intensity of pregnancy planning was used as the dependent variable in a multivariate linear regression model, and as a basis for assessing vitamin use according to four levels of planning. RESULTS: A majority of women scored high for intensity of pregnancy planning. Planning intensity score increased with age and was higher among women who attended university, had a family income greater than CAD $30,000, and were married. Vitamin use in the period prior to conception occurred with a frequency of 27.5%, increasing moderately with planning intensity scores. Overall, only 13.5% of fetuses were exposed to adequate doses of folic acid. CONCLUSION: A promotion campaign selectively targeting women likely to plan a pregnancy could have a significant impact in reducing neural tube defect incidence.

Adult↗
PubMed1995

Contamination of local wildlife following a fire at a polychlorinated biphenyls warehouse in St Basile le Grand, Quebec, Canada.

This study on wildlife contamination, one to ten months after the polychlorinated biphenyls (PCB) fire in St Basile le Grand, Quebec, shows that the fire increased PCB and polychlorinated dibenzofuran (PCDF) levels in animals. From the data, it was not possible to detect a significant increase in polychlorinated dibenzodioxin (PCDD) levels after the fire. Given the relatively small sample size, the differences in concentrations could not be estimated precisely. However, it can be asserted with a 95% confidence level that mean concentrations of total PCBs were roughly 2 to 6 times higher in the area contaminated by the plume of smoke, concentrations of homologues with 3 chlorine atoms were 1 to 4 times higher, and levels of homologues with 5 to 9 chlorine atoms were 3 to 13 times higher. The relative deviations between concentrations in areas under the plume and those outside it were similar for all animals sampled. With regard to total PCDFs, mean concentrations were significantly higher under the smoke plume than outside it for all species. This observation is linked to homologues with 4, 5 and 7 chlorine atoms for which significant differences were detected between the two areas. The fire had no effect on the pattern of PCB congeners found in the tissue of animals in the region. Congeners Nos. 153, 180, 138 and 118 represent approximately 50% of total PCBs. Although PCB and PCDF concentrations were higher in the tissue of local wildlife species exposed to the fire, they were nonetheless comparable to those found in other urban and agricultural areas in Canada. These concentrations, in 2,3,7,8-TCDD toxic equivalents, were much lower than those observed in the wake of three other major incidents involving PCDDs (Elgin, Florida; Times Beach, Missouri; and Seveso, Italy).(ABSTRACT TRUNCATED AT 250 WORDS)

Amphibians↗
PubMed1993

Genetic epidemiology of sensorimotor polyneuropathy with or without agenesis of the corpus callosum in northeastern Quebec.

Sensorimotor polyneuropathy with or without agenesis of the corpus callosum (McKusick number 218000) is a disorder that has a high frequency in Saguenay-Lac-St-Jean (SLSJ), a geographically isolated region of north-eastern Quebec. The incidence at birth and the carrier rate were estimated, respectively, at 1/2117 liveborns and 1/23 inhabitants. Remote consanguinity was found in several polyneuropathic families while the mean kinship coefficient was 2.7 times higher in the polyneuropathic group than in control groups. The birth places of the individuals with sensorimotor polyneuropathy and their parents did not show a clustered nonuniform distribution. The genealogical reconstruction suggests that the high incidence of polyneuropathy in SLSJ is likely to be the result of a founder effect. It also suggests that a unique mutation accounts for most, if not all, of the cases of sensorimotor polyneuropathy known in this region.

Agenesis of Corpus Callosum↗
PubMed1993

Community empowerment: the alternative resources movement in Quebec.

In order to achieve true community participation in mental health care, a redistribution of decision-making power is needed. Currently, this power is almost exclusively in the hands of psychiatric institutions and the state. Community participation would require greater representation from community organizations. This paper describes the history of the alternative resources movement in Quebec. This movement has challenged the health care system and promoted innovative therapeutic approaches. In this process, community organizations have been faced with the difficult task of gaining more power while maintaining strong links with the communities they serve.

Adult↗