Environmental pollutants are becoming increasingly conspicuous in modern society. Lung function testing is one of the ways of assessing their impact on the health of the public. However lung function tests present large between individual variation, some of the determinants of which are race, sex, age and morphometric characteristics. These are generally taken into account using prediction formulae derived from the best fit equation to a set of values observed in a particular survey. / In the present study new formulae were developed which used current physiological knowledge of the determinants of lung function. These formulae together with some of the models in current use were fitted to a single training data set and the homogeneity of the fit across all ages was then compared. The models so developed, together with some of the formulae proposed in the literature were then used to predict the values of certain lung function tests in two independent populations to assess the bias of the predictions. / In the working age range (25 to 65) in males all formulae yielded comparable predictions; however in females and teenagers of both sexes the proposed model or the model proposed by Schoenberg predicted the data better. / The model proposed included a smoking module. However in the population studied ex smokers were found to present better lung function than non smokers, so that the model proposed to evaluate the effect of smoking is only applicable for current smokers. The effect of smoking was acceptably predicted for the tests derived from the forced expiratory maneuver. / One of the possible reasons why the proposed model did not fit the training data better than the empirical models may lie in the incomplete knowledge of the determinants of lung function. Further research is needed to identify such determinants and to find an objective and simple methodology for their evaluation.

Seventy-five workers exposed to styrene in four reinforced plastics plants in the Montreal area have taken part in this study. All subjects were tested for peripheral nervous system functioning during a period of continuous exposure; 12 were re-evaluated after a lay-off period without exposure. During the period of continuous exposure, a dose-response relationship between the environmental exposure and the sensory nerve conduction velocity (NCV) was demonstrated. Almost all workers exposed for at least one month to levels of styrene above 100 ppm had a nerve conduction deficit. The effects observed were not related to cumulated exposure. After a period of lay-off, slight changes in NCV were observed in accordance with a functional improvement. No excess in symptoms reported in relation to a NCV deficit was demonstrated. Biological measures of styrene absorption and excretion were used; they appeared to be better predictors of neurotoxic effects than environmental measures of styrene exposure.

Asthma is a heterogeneous disorder, and the prevalence is increasing worldwide. The BCG vaccine is hypothesized to lower the risk of asthma by modulating specific aspects of T-cell mediated immunity (termed Th1 and Th2). We conducted a case-control study to determine the relationship between BCG vaccine given to children born and raised in Quebec and asthma in adult subjects. 93 case subjects with a clinical diagnosis of asthma and 118 control subjects without asthma answered a standardized questionnaire, and BCG vaccination status was verified in a central registry. After adjusting for potential confounders, vaccination with BCG after the age of one was associated with a reduced odds of adult-onset asthma (odds ratio: 0.3 (0.1-0.98)), and specifically of adult-onset atopic asthma (odds ratio: 0.2 (0.1-0.9)). These results suggest a critical time frame in immune system maturation during which administration of BCG vaccine may lower the risk of adult-onset asthma.

A leading hypothesis for the etiology of multiple sclerosis (MS) is that a delayed infection by Epstein-Barr Virus (EBV) generates an abnormal immune response, thereby inducing the disease. EBV is ubiquitous. While asymptomatic in children, the infection produces the clinical entity infectious mononucleosis (IM) when it is delayed until adolescence or young adulthood. Typically, case-control studies have measured exposure to EBV by serology assaying EBV antibodies or by IM self-report. The findings of these studies are not consistent. / Part of the problem in establishing a definite causal relationship between EBV and MS in case-control studies is related to exposure measurement and misclassification. Since neither EBV serology or IM self-report represent a 'gold standard' for exposure, particularly of delayed exposure, it is difficult to estimate the exposure misclassification that would occur in a case-control study, and the subsequent bias in the odds ratio (OR). / These results support that EBV serology is not a good measure of delayed EBV infection due to its lack specificity, and that estimates of association between MS and EBV serology may overestimate or underestimate the OR between MS and IM. EBV is extremely prevalent, and likely to be differentially misclassified by serology. We therefore recommend the use of IM self-report for future case-control studies of MS and EBV.

Background. Little attention has been given to the assessment of quality of life (QOL) in injection drug users (IDUs). Some studies have suggested that existing measures are inadequate for use in IDUs. / Objectives. The objectives were: (1) to develop and evaluate a QOL measure for IDUs, the Injection Drug User Quality of Life Scale (IDUQOL), (2) to describe the QOL of cocaine and heroin IDUs and identify its constituents and correlates, and (3) to describe the relation between the QOL of cocaine and heroin IDUs and the use of public health programs. / Methods. The psychometric properties of the IDUQOL were assessed in 61 IDUs, 85% of whom were re-interviewed within 4-weeks. The Flanagan Quality of Life Scale was used to assess the criterion validity of the IDUQOL. The IDUQOL was subsequently applied in a study of 260 Montreal IDUs to identify their most important life areas. Associations between QOL and the use of public health programs and other correlates were assessed using multiple linear regression. / Results. The IDUQOL had good psychometric properties: the test-retest reliability was within accepted standards (intraclass correlation coefficient = 0.71) and the concurrent criterion validity between the IDUQOL and the Flanagan was moderate (Pearson coefficient = 0.57). In the study of 260 Montreal IDUs, housing was the most frequently selected life area of cocaine IDUs. Heroin IDUs most frequently selected money and feeling good about yourself. Both cocaine and heroin IDUs were generally dissatisfied with how these life areas fared. QOL was significantly better for HIV positive IDUs and IDUs who used meal programs, and was worse for IDUs who attended shelters and emergency departments. No strong relations were found with needle exchange program use, methadone or other drug treatment. / Conclusion. The IDUQOL appeared to be a conceptually clear and culturally relevant QOL instrument with good psychometric properties. Programs that address the life conditions of IDUs might be needed foremost to other initiatives. Understanding the constituents and correlates of the QOL of IDUs is important to the development of more effective programs to curb disease transmission, and improve the well-being of IDUs.

Objective. The aim of the study was to assess the effectiveness of antenatal mebendazole plus iron supplementation versus placebo plus iron supplementation on birthweight in a highly hookworm-endemic area. / Methods. This study was a double-blind randomized controlled trial set in rural and peri-urban communities in the Peruvian Amazon region. A total of 1042 second trimester pregnant women between the ages of 18 and 44 years were recruited from April to November 2003, and followed to July 2004. Women were randomly assigned to receive either mebendazole (500 mg single dose) plus iron supplements (60 mg elemental iron daily) or placebo plus iron supplements. The primary outcome was mean infant birthweight and secondary measures included proportion of low birthweight (<2500g) and maternal anemia. Adverse birth outcomes were also recorded. / Results. The prevalence of hookworm infection was 47.5%. There were no differences between intervention groups in mean birthweight (3104 g vs 3090 g, p=0.629), proportion of low birthweight (8.1% vs 8.7%, p=0.755) or maternal anemia in the 3rd trimester (33.0% (158/479) vs 32.3% (152/471), p=0.815). However, the proportion of very low birthweight (<1500g) was significantly lower in the mebendazole group (0% (0/479) vs 1.5% (7/471), p=0.007). No statistically significant difference (p=0.664) in adverse birth outcomes (miscarriages, malformations, stillbirths, early neonatal deaths and premature babies) was found between the mebendazole group and the placebo group (28 versus 31, respectively). / Conclusion. This trial provides additional evidence for the use of anthelminthics, over and above iron supplementation, within antenatal care programs in hookworm-endemic areas.

Canadian public health agencies have a mandate to monitor the prevalence, incidence and patterns of chronic disease. These agencies are increasingly using administrative health data for these purposes. However, valid use of administrative data for chronic disease surveillance requires an understanding of some inherent limitations. Health-selective migration, which occurs when people migrate differentially by health status, is a limitation that has not been estimated in administrative data sources. To investigate this issue, we estimated health-selective migration in a cohort of systemic lupus erythematosus (SLE) and Sjogren's patients, identified from physician and hospital claims databases in Quebec and compared them to rates in an age and sex frequency-matched sample from Montreal, Quebec using hierarchical logistic regression. The association between disease and migration was modified by both age and disease duration. Both SLE and Sjogren's patients migrated less than controls when young. For example, 30-year-old SLE (OR 0.54, 95% CrI 0.45-0.64) and Sjogren's (OR 0.41, 95% CrI 0.28-0.56) patients with two years of disease duration had lower odds of moving than frequency-matched controls. Above age 50, the odds of migration in SLE and Sjogren's patients was comparable or slightly higher than in controls. Patients at age 70 with two years of disease duration had an OR of moving of 1.29 (95% CrI 1.04-1.58) in SLE and 1.09 (95% CrI 0.81-1.42) in Sjogren's. The associations between migration and disease duration in SLE and Sjogren's were qualitatively different. One year of SLE duration was associated with an OR of 0.96 (95% CrI 0.93-0.98) and one year of Sjogren's duration was associated with an OR of 1.05 (95% CrI 1.00-1.10). Results were similar when using SLE and Sjogren's patients pre-diagnosis as the control and when looking at migration on a regional scale. Overall, SLE and Sjogren's have an impact on migration rates which varies by age, disease and disease duration. / Les organismes canadiens de santé publique ont le mandat de surveiller la prévalence, incidence, et les tendances des maladies chroniques dans notre pays. De plus en plus, ces agences utilisent des bases de données administratives sur la santé à ces fins. Cependant, l'utilisation valable de ces sources de données pour la surveillance des maladies chroniques exige une compréhension de certaines limites inhérentes, en particulier la migration sélective par l'état de santé, ce qui se produit lorsque les gens migrent de façon différente du à leur état de santé. Nous avons effectué une évaluation des déménagements chez des patients ayant le lupus érythémateux disséminé ou le syndrome de Sjogren's tel qu'identifiés dans les données des réclamations des médecins et des hôpitaux du Québec. La régression logistique hiérarchique a été utilisée pour comparer les taux de migration chez des patients atteints de lupus ou de Sjogren's aux taux de déménagement dans un échantillon de concordance des fréquences par âge et par sexe de la population de Montréal.Dans notre échantillon, l'association entre les maladies et la migration a démontré des modifications par l'âge du patient et la durée de sa maladie. Les patients lupiques ou ayant le Sjogren's déménagent moins quand ils sont plus jeunes. Par exemple, à 30 ans et atteint de l'une de ces maladies depuis deux ans les patients lupiques (RC: 0.54, intervalle crédible (ICr) 95% 0.45-0.6) et ceux atteints de Sjogren's (RC: 0.41, ICr 95% 0.28-0.56) ont des cotes de déménagement moins élevés que ceux du groupe témoin. Par contre, à 50 ans et plus, les cotes de migration des patients lupiques et ayant le Sjogren's sont comparables et même légèrement supérieures à celles du groupe témoin. Les patients âgées de 70 ans étant malades depuis 2 ans ont un rapport de cotes de déplacement de 1,29 (ICr 95%: 1,04-1,58) pour ceux atteints du lupus et de 1,09 (ICr 95%, 0,81-1,42) pour ceux ayant le Sjogren's. Aussi, l'association entre la migration et la durée de la maladie était qualitativement différente entre les patients lupiques et les patients atteints de Sjogren's. Par exemple, les patients ayant le lupus depuis un an ont montrés un rapport de cotes de 0,96 (ICr 95%, 0,93-098) et les patients atteint de Sjogren's ont montrés un rapport de cotes de 1,05 (ICr 95% 1,00-1,10) par an de durée de maladie.Les résultats étaient similaires lorsque le groupe témoin était composé de patients qui n'avaient pas encore été diagnostiqués ou lorsqu'on regarde les migrations à l'échelle régionale. Ce mémoire supporte l'idée que les maladies chroniques peuvent affecter les taux de migration et que ceux-ci peuvent varier en fonction de l'âge du patient, de la maladie et de la durée de cette maladie.

Over the last few decades breastfeeding (BF) has become a World Health Organization (WHO) sanctioned public health priority due to its positive health outcomes, both for the mother and her child. In 2001, the province of Quebec issued a BF policy L'Allaitement maternel au Québec: Lignes directrices, (thereafter LD), aimed at implementing global health recommendations on infant feeding (WHO/UNICEF). Although this policy action has resulted in tremendous increase of BF initiation rate, BF duration remains below WHO standards, particularly among specific sociodemographic groups. Drawing on data from a large, multi-site qualitative study in Quebec, this study analyzes women's experience of BF, and seeks to investigate the gap between policy and its implementation, and in turn how women interpret, negotiate and/or resist current recommendations in their infant feeding practices. The focus of the study is the comparison of women's narratives (52 women participated in 11 Focus Groups) and lived experience of varying health care settings with differing degrees of compliance to LD (high and low implementation of the Baby-Friendly Initiative). This work examines BF beyond its biological dimension, and it tackles how public health policies and quality of delivery services influence women's choices and practices of infant feeding, and concur to women's experience and self-perception of motherhood and womanhood.Given that this policy evaluation study draws from women's narratives from various life contexts (rural and urban settings), my findings will contribute significantly to future BF policies in Québec as well as to give valuable insight on a global level. / Depuis plusieurs décennies, l'allaitement est une question de santé publique prioritaire pour l'Organisation mondiale de la Santé (OMS) en raison de ses effets positifs pour la mère et pour son enfant. En 2001, la province de Québec a émis une politique d'allaitement, L'allaitement maternel au Québec : lignes directrices, (ci-après LD) qui visait à mettre en œuvre les recommandations internationales en matière d'alimentation du nourrisson (OMS/UNICEF). Bien que l'introduction de cette politique ait entraîné une forte augmentation du nombre de mères amorçant l'allaitement, la durée de l'allaitement reste en-deçà des standards préconisés par l'OMS, et particulièrement parmi certains groupes sociodémographiques. S'appuyant sur des données recueillies dans le cadre d'une large étude qualitative multicentrique réalisée au Québec, la présente analyse examine l'expérience de mères au regard de l'allaitement et cherche à appréhender le décalage existant entre la politique promue et sa mise en œuvre effective. Elle tente en même temps de mettre au jour la façon dont les mères interprètent et négocient les recommandations en matière d'alimentation infantile, voire comment elles y résistent. Le point central de cette analyse se situe dans la comparaison de témoignages de femmes (52 femmes ont pris part à 11 groupes de discussion focale) et de leur expérience à l'égard des services offerts par des établissements de santé ayant différents degrés de conformité aux LD (mise en œuvre de l'Initiative des amis des bébés [IAB] faible ou élevée). Ce travail examine la question de l'allaitement au-delà de sa dimension biologique et s'attache à apprécier dans quelle mesure les politiques de santé publique et la qualité des services influencent les choix des femmes et leurs pratiques d'alimentation infantile, et comment, au final, cela agit sur leur expérience et sur leur perception propre de la maternité et de la féminité.Étant donné que l'évaluation de cette politique publique repose sur des témoignages de femmes aux contextes de vie variés (milieux urbains et ruraux), mes conclusions contribueront d'une manière significative à la mise en place de futures politiques d'allaitement au Québec tout en apportant un éclairage précieux à un niveau plus global.

Adverse drug reactions (ADRs) present heavy burdens for the public health care system, and current pharmacovigilance activities are challenged by the under-reporting of ADRs in spontaneous reporting systems and a lack of incentive for industry to conduct rigorous post-approval research. As part of a new lifecycle approach to drug regulation, Health Canada recently announced plans to develop a new health product vigilance framework that will allocate drug safety resources using prioritization schemes focused on higher risk. These plans include the development of official policy requirements for industry to submit formal Risk Management Plans to Health Canada. This thesis argues that this approach is limited by lack of transparency and standardization, burdens on health care practitioners, and a risk of causing treatment disparities. This thesis presents alternative measures for improving post-market drug safety surveillance through initiatives for enhancing ADR data collection systems. These include the use of electronic health records for automated reporting by health care professionals, the screening of health-related social media sites for ADR reports, and the use of internet-based prescription monitoring systems to solicit ADR reports. This thesis also proposes options for improved post-approval research efforts. These include enhanced legislative authority for Health Canada to mandate post-market research commitments to drug sponsors as conditions of approval, offering extensions on data protection to sponsors in exchange for comparative effectiveness research, implementing mandatory industry-sourced funding for objective third-party research, and ensuring that the Drug Safety and Effectiveness Network contains adequate patient representation. In the current context of limited health care resources, these alternatives merit further consideration, including consultation and validation with relevant stakeholders, in order determine the most value-added methods for improving drug safety surveillance. / Les manifestations indésirables dues aux médicaments représentent une lourde charge pour le la santé publique d'autant plus que les activités actuelles de pharmacovigilance sont limitées, d'une part par le fait qu'un bon nombre de rapports spontanés ne sont pas comptabilisés dans les différentes bases de données et d'autre part parce qu'il n'existe pas suffisamment d'incitatifs pour encourager l'industrie à mener des recherches systématiques après qu'un médicament ait été approuvé. Dans le cadre d'une nouvelle approche de la réglementation des médicaments basée sur le cycle de vie de ceux-ci, Santé Canada a récemment annoncé son intention de développer un nouveau cadre sur la surveillance des produits de santé qui permettra d'allouer à l'innocuité des médicaments les ressources selon des priorités établies en fonction d'un risque plus élevé. Ce projet inclut le développement d'une politique officielle pour exiger de l'industrie qu'elle soumette des plans concrets de gestion du risque à Santé Canada. Ce mémoire soutient que cette approche contient des limitations causées par un manque de transparence et d'uniformisation, qu'elle représente un fardeau additionnel pour les professionnels de la santé et qu'elle risque de causer des disparités dans le traitement des données recueillies.Ce mémoire présente des mesures alternatives visant à améliorer le suivi au sujet de l'innocuité des médicaments une fois que ces derniers sont sur le marché, en utilisant des initiatives visant à améliorer les systèmes de collection des rapports de manifestations indésirables. Ces mesures incluent l'utilisation de registres de santé informatisés pour les rapports automatisés provenant des professionnels de la santé, le criblage de sites Internet de type médias sociaux ayant un lien avec les rapports de manifestations indésirables et l'utilisation de systèmes de surveillance Internet pour solliciter les rapports de manifestations indésirables. Ce mémoire propose également diverses options pour l'amélioration des efforts de recherche une fois le médicament approuvé. Les propositions incluent une autorité législative plus grande pour Santé Canada pour inclure comme condition d'approbation des engagements fermes de la part des fabricants de médicaments d'effectuer de la recherche post-commercialisation, offrir aux compagnies des extensions pour la protection de données en échange de recherche comparative sur l'efficacité, la mise en œuvre obligatoire de sources de financement provenant de l'industrie pour des recherches indépendantes effectuées par un tiers-parti et assurer que le Réseau sur l'innocuité et l'efficacité des médicaments contient une représentation adéquate des patients. Dans le contexte actuel où les ressources allouées au système de santé sont limitées, ces alternatives méritent qu'on s'y attarde davantage, et que l'on inclue la consultation et la validation avec les parties concernées, dans le but de déterminer les méthodes à plus grande valeur ajoutée pour l'amélioration de la surveillance de l'innocuité des médicaments.

<p> <b>Background:</b>Studies suggest first generation status is protective regarding obesity/diet, but not physical activity. We sought to determine whether generational status of Hispanic and Black NYC children correlates with obesity, physical activity, and diet. <b>Methods:</b> Children ages 6-8 who could be classified as first/second/third generation from the Growing Up Healthy study (n=456) were included. BMI was calculated using age- and gender-specific CDC norms. Mean steps were recorded with pedometers. Physical/sedentary activity and frequency of fast food/restaurant meals were assessed via survey. T-tests, Kruskal-Wallis, Chi-square, and Fisher's exact tests were performed. <b> Findings: </b>While screen and sedentary time were highest in third generation children (p=0.03, p=0.00), they reported more MET-hours and unscheduled physical activity (p=0.04, p=0.01). Fast food consumption increased with generation among Hispanics (n=267, p=0.01). <b>Conclusions: </b>Sedentary behavior and fast food consumption were highest among third generation children. Ethnic-specific trends in physical activity and diet reinforce the need for additional research. </p>