Search

La surveillance de la santé consiste en l’utilisation systématique et continue de données sur la santé recueillies régulièrement en vue d’orienter les mesures de santé publique en temps opportun. Ce document décrit la création et l’essor des systèmes nationaux de surveillance au Canada et les répercussions de ces systèmes sur la prévention des maladies chroniques et des blessures. En 2008, les auteurs ont commencé à retracer l’historique des débuts de la surveillance nationale des maladies chroniques au Canada, en commençant à 1960, et ils ont poursuivi leur examen jusqu’en 2000. Une publication de 1967 a retracé l’historique de la création du Laboratoire d’hygiène de 1921 à 1967. Notre étude fait suite à cette publication et décrit l’historique de l’établissement de la surveillance nationale des maladies chroniques au Canada, à la fois avant et après la création du Laboratoire de lutte contre la maladie (LCDC).

Background. Cancer and cardiovascular diseases are the leading causes of mortality and morbidity worldwide. The purpose of this meta-analysis is to synthesize the evidence evaluating the association between obesity and 13 cancers shown previously to be significantly associated with obesity. Methods. Relevant papers from a previously conducted review were included in this paper. In addition, database searches of Medline and Embase identified studies published from the date of the search conducted for the previous review (January, 2007) until May, 2011. The reference lists of relevant studies and systematic reviews were screened to identify additional studies. Relevance assessment, quality assessment, and data extraction for each study were conducted by two reviewers independently. Meta-analysis was performed for men and women separately using DerSimonian and Laird’s random effects model. Results. A total of 98 studies conducted in 18 countries from 1985 to 2011 were included. Data extraction was completed on the 57 studies judged to be of strong and moderate methodological quality. Results illustrated that obese men were at higher risk for developing colon (Risk Ratio (RR), 1.57), renal (1.57), gallbladder (1.47), pancreatic (1.36), and malignant melanoma cancers (1.26). Obese women were at higher risk for esophageal adenocarcinoma (2.04), endometrial (1.85), gallbladder (1.82), renal (1.72), pancreatic (1.34), leukemia (1.32), postmenopausal breast (1.25), and colon cancers (1.19). Conclusions. The results of this meta-analysis illustrate a significant, positive, and, for some cancers, strong association between obesity and cancer incidence. Given that approximately 23% of Canadians are obese, a significant proportion of cancer in Canada could be avoided if obesity was eliminated or significantly reduced.

Background: Accurate estimation of the case-fatality (CF) rate, or the proportion of cases that die, is central to pandemic planning. While estimates of CF rates for past influenza pandemics have ranged from about 0.1% (1957 and 1968 pandemics) to 2.5% (1918 pandemic), the official World Health Organization estimate for the current outbreak of H5N1 avian influenza to date is around 60%. Methods and results: The official estimate of the H5N1 CF rate has been described by some as an over-estimate, with little relevance to the rate that would be encountered under pandemic conditions. The reasons for such opinions are typically: (i) numerous undetected asymptomatic/mild cases, (ii) under-reporting of cases by some countries for economic or other reasons, and (iii) an expected decrease in virulence if and when the virus becomes widely transmitted in humans. Neither current data nor current literature, however, adequately supports these scenarios. While the real H5N1 CF rate could be lower than the current estimate of 60%, it is unlikely that it will be at the 0.1–0.4% level currently embraced by many pandemic plans. We suggest that, based on surveillance and seroprevalence studies conducted in several countries, the real H5N1 CF rate should be closer to 14–33%. Conclusions: Clearly, if such a CF rate were to be sustained in a pandemic, H5N1 would present a truly dreadful scenario. A concerted and dedicated effort by the international community to avert a pandemic through combating avian influenza in animals and humans in affected countries needs to be a global priority.

Aims: Grading of evidence of the effectiveness of health promotion interventions remains a priority to the practise of evidence-based health promotion. Several authors propose grading the strength of evidence based on a hierarchy: convincing, probable, possible and insufficient; or strong, moderate, limited and no evidence. Although these grading hierarchies provide simple and straightforward rankings, the terms that describe the categories in the hierarchies, however, do not explain, in an explicit manner, in what way the strength of the evidence in one category is more, or less, superior than that in another. Methods: To enhance the explanatory power of the hierarchy, we propose that evidence be classified into three grades, each with a short explanatory note on the basis of three criteria: the degree of association between the intervention under study and the outcome factors, the consistency of the findings from different studies, and whether there is a known cause–effect mechanism for the intervention under study and the outcome factors. Conclusion: For more in-depth grading, a three-grade expanded hierarchy is also recommended. Examples are given to illustrate our proposed grading schemes.

The objective of this study was to investigate whether or not education about the concept of uncertainty reduced variability in treatment decision-making. Three small groups of dentists in North York, Canada were asked to make restorative treatment decisions about simulated bitewing radiographs. They subsequently took part in a seminar about variations in perception and judgement and were given explanations of sensitivity, specificity and receiver operating characteristic (ROC) curve analysis. A repeat reading of the radiographs was then performed by both test and control groups. Results indicated that the intervention increased the accuracy, and decreased the variability of dentists' restorative treatment decisions. Kappa statistics were 0.33, 0.34 and 0.31 before the seminar, and 0.40, 0.43 and 0.41 after the seminar. Standard errors for kappas were 0.06, 0.05 and 0.05 before the seminar, and 0.02, 0.02 and 0.05 after the seminar. The area under the ROC curve was 0.7136 before the seminar and 0.7835 after the seminar. The data demonstrate that the dentists' decisions were less variable and more accurate following the educative intervention. This study suggests that there is potential for improving consistency and accuracy in clinical decision-making through education in probabilistic reasoning.

As public health professionals, we recognise a gap between scientists and decision makers. Firstly, communication is a problem. Scientists and decision makers do not use the same language. Because decision makers are usually not current in complex analytical approaches, study results must be put forth in a compelling manner—for example, through visually interesting presentations that accurately and effectively summarise complex analyses. Secondly, time is a problem. Decision makers seldom have time to read …

This paper proposes a new pair of indices, the »predictive powers«, for measuring the predictive accuracy (predictivity) of screening tests.Sensitivity and specificity are indices for measuring the validity of a test. They give the probability of a certain test result given a substance of known condition (a carcinogen or a non-carcinogen). They do not describe the predictive accuracy of a test, which is the probability of a certain condition (a carcinogen or a non-carcinogen) given a known test result. Predictive values are unsuitable measures for characterizing a test since they are seriously affected by the prevalence of carcinogens. However, the predictive powers do not have this limitation and are shown to be useful indices for the purpose of rating the predictive accuracies of various screening tests.

A cohort of 1624 employees (957 men, 667 women) in a rubber factory in Shanghai have been followed up since 1972 and their 12 year mortality experience is presented. The relative risk of lung cancer for smokers was 8.5 for men and 11.4 for women and for rubber workers exposed to curing agents or talc powder 3.2 for men and 4.6 for women.

An exploratory study of brain tumors in adults was carried out using 215 cases diagnosed in Southern Ontario between 1979 and 1982, with an individually matched, hospital control series. Significantly elevated risks were observed for reported use of spring water, drinking of wine, and consumption of pickled fish, together with a significant protective effect for the regular consumption of any of several types of fruit. While these factors are consistent with a role for N-nitroso compounds in the etiology of these tumors, for several other factors related to this hypothesis, no association was observed. Occupation in the rubber industry was associated with a significant relative risk of 9.0, though no other occupational associations were seen. Two previously unreported associations were with smoking nonfilter cigarettes with a significant trend and with the use of hair dyes or sprays. The data do not support an association between physical head trauma requiring medical attention and risk of brain tumors and indicate that exposure to ionizing radiation and vinyl chloride monomer does not contribute any appreciable fraction of attributable risk in the population studied. The findings warrant further detailed investigation in future epidemiologic studies.