Surveillance and Epidemiology Unit

Halifax, Canada

Surveillance and Epidemiology Unit

Halifax, Canada

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Otterstatter M.C.,Public Health Agency of Canada | Brierley J.D.,University of Toronto | De P.,Cancer Control Policy and Information | Ellison L.F.,Statistics Canada | And 4 more authors.
Canadian Journal of Gastroenterology | Year: 2012

BACKGROUND: Esophageal adenocarcinoma has one of the fastest rising incidence rates and one of the lowest survival rates of any cancer type in the Western world. However, in many countries, trends in esophageal cancer differ according to tumour morphology and anatomical location. In Canada, incidence and survival trends for esophageal cancer subtypes are poorly known. METHODS: Cancer incidence and mortality rates were obtained from the Canadian Cancer Registry, the National Cancer Incidence Reporting System and the Canadian Vital Statistics Death databases for the period from 1986 to 2006. Observed trends (annual per cent change) and five-year relative survival ratios were estimated separately for esophageal adenocarcinoma and squamous cell carcinoma, and according to location (upper, middle, or lower one-third of the esophagus).Incidence rates were projected up to the year 2026. RESULTS: Annual age-standardized incidence rates for esophageal cancer in 2004 to 2006 were 6.1 and 1.7 per 100,000 for males and females, respectively. Esophageal adenocarcinoma incidence rose by 3.9% (males) and 3.6% (females) per year for the period 1986 to 2006, with the steepest increase in the lower one-third of the esophagus (4.8% and 5.0% per year among males and females, respectively). In contrast, squamous cell carcinoma incidence declined by 3.3% (males) and 3.2% (females) per year since the early 1990s. The five-year relative survival ratio for esophageal cancer was 13% between 2004 and 2006, approximately a 3% increase since the period from 1992 to 1994. Projected incidence rates showed increases of 40% to 50% for esophageal adenocarcinoma and decreases of 30% for squamous cell carcinoma by 2026. DISCUSSION: Although esophageal cancer is rare in Canada, the incidence of esophageal adenocarcinoma has doubled in the past 20 years, which may reflect the increasing prevalence of obesity and gastroesophageal reflux disease. Declines in squamous cell carcinoma may be the result of the decreases in the prevalence of smoking in Canada. Given the low survival rates and the potential for further increases in incidence, esophageal adenocarcinoma warrants close attention. ©2012 Pulsus Group Inc. All rights reserved.


Porter G.A.,Dalhousie University | Porter G.A.,Cancer Outcomes Research Program | Urquhart R.,Cancer Outcomes Research Program | Bu J.,Cancer Outcomes Research Program | And 4 more authors.
BMC Cancer | Year: 2011

Background: Adequate nodal harvest (≥ 12 lymph nodes) in colorectal cancer has been shown to optimize staging and proposed as a quality indicator of colorectal cancer care. An audit within a single health district in Nova Scotia, Canada presented and published in 2002, revealed that adequate nodal harvest occurred in only 22% of patients. The goal of this current study was to identify factors associated with adequate nodal harvest, and specifically to examine the impact of the audit and feedback strategy on nodal harvest.Methods: This population-based study included all patients undergoing resection for primary colorectal cancer in Nova Scotia, Canada, from 01 January 2001 to 31 December 2005. Linkage of the provincial cancer registry with other databases (hospital discharge, physician claims data, and national census data) provided clinicodemographic, diagnostic, and treatment-event data. Factors associated with adequate nodal harvest were examined using multivariate logistic regression. The specific interaction between year and health district was examined to identify any potential effect of dissemination of the previously-performed audit.Results: Among the 2,322 patients, the median nodal harvest was 8; overall, 719 (31%) had an adequate nodal harvest. On multivariate analysis, audited health district (p < 0.0001), year (p < 0.0001), younger age (p < 0.0001), non-emergent surgery (p < 0.0001), more advanced stage (p = 0.008), and previous cancer history (p = 0.03) were associated with an increased likelihood of an adequate nodal harvest. Interaction between year and audited health district was identified (p = 0.006) such that the increase in adequate nodal harvest over time was significantly greater in the audited health district.Conclusions: Improvements in colorectal cancer nodal harvest did occur over time. A published audit demonstrating suboptimal nodal harvest appeared to be an effective knowledge translation tool, though more so for the audited health district, suggesting a potentially beneficial effect of audit and feedback strategies. © 2011 Porter et al; licensee BioMed Central Ltd.


Murray C.L.,Memorial University of Newfoundland | Walsh G.W.,Surveillance and Epidemiology Unit | Connor Gorber S.,Public Health Agency of Canada
Journal of Obesity | Year: 2012

Objectives. To determine whether obesity correction equations for the Canadian general population, which are dependent on the prevalence of obesity, are appropriate for use in Atlantic Canada, which has the highest obesity rates in the country. Also, to compare the accuracy of the national equations to equations developed specifically for the Atlantic Canadian population. Methods. The dataset consisted of Canadian Community Health Survey (CCHS) 2007-2008 data collected on 17,126 Atlantic Canadians and a subsample of adults, who provided measured height and weight (MHW) data. Atlantic correction equations were developed in the MHW subsample. Using separate multiple regression models for men and women, self-reported body mass index (BMI) was corrected by multiplying the self-reported estimate by its corresponding model coefficient and adding the model intercept. Paired t-tests were used to determine whether corrected mean BMI values were significantly more accurate (i.e., closer to measured data) than the equivalent means based on self-reported data. The analyses were repeated using the national equations. Results. Both the Atlantic and the national equations yielded corrected obesity estimates that were significantly more accurate than those based on self-report. Conclusion. The results provide some evidence of the generalizability of the national equations to atypical regions of Canada. © 2012 Cynthia L. Murray et al.


Lavergne M.R.,Dalhousie University | Johnston G.M.,Dalhousie University | Johnston G.M.,Surveillance and Epidemiology Unit | Gao J.,Surveillance and Epidemiology Unit | And 2 more authors.
Journal of Pain and Symptom Management | Year: 2011

Context: Palliative care researchers face challenges recruiting and retaining study subjects. Objectives: This article investigates selection, study site, and participation biases to assess generalizability of a cost analysis of palliative care program (PCP) clients receiving care at home. Methods: Study subjects' sociodemographic, geographic, survival, disease, and treatment characteristics were compared for the same year and region with those of three populations. Comparison I was with nonstudy subjects enrolled in the PCP to assess selection bias. Comparison II was with adults who died of cancer to assess study site bias. Comparison III was with study-eligible persons who declined to participate in order to assess participation bias. Results: Comparison I: When compared with the other 1010 PCP clients, the 50 study subjects were on average 3.6 years younger (P = 0.03), enrolled 70 days longer in the PCP (P < 0.001), lived 6.7 km closer to the PCP (P < 0.0001), and were more likely to have cancer (96.0% vs. 86.4%, P = 0.05). Comparison II: Compared with all cancer decedents, the 45 study subjects who died of cancer were on average 7.0 years younger (P < 0.001), lived 2.7 km closer to the PCP (P < 0.001), and were more likely to have had radiotherapy (62.2% vs. 33.8%, P < 0.0001) and medical oncology (28.9% vs. 14.8%, P = 0.01) consultations. Comparison III: The 50 study subjects lived on average 42 days longer after their diagnosis (P = 0.03) and 2.6 km closer to the PCP (P = 0.01) than the 110 eligible persons who declined to participate. Conclusion: If the study findings are applied to populations that differ from the study subjects, inaccurate conclusions are possible. © 2011 Published by Elsevier Inc. on behalf of U.S. Cancer Pain Relief Committee.


Angelski C.,University of Alberta | Angelski C.,Edmonton Clinic Health Academy | Fernandez C.V.,Dalhousie University | Weijer C.,University of Western Ontario | Gao J.,Surveillance and Epidemiology Unit
BMC Medical Ethics | Year: 2012

Background: Publication of ethically uncertain research occurs despite well-published guidelines set forth in documents such as the Declaration of Helsinki. Such guidelines exist to aide editorial staff in making decisions regarding ethical acceptability of manuscripts submitted for publication, yet examples of ethically suspect and uncertain publication exist. Our objective was to survey journal editors regarding practices and attitudes surrounding such dilemmas. Methods. The Editor-in-chief of each of the 103 English-language journals from the 2005 Abridged Index Medicus list publishing original research were asked to complete a survey sent to them by email between September-December 2007. Results: A response rate of 33% (n = 34) was obtained from the survey. 18% (n = 6) of respondents had published ethically uncertain or suspect research within the last 10 years. 85% (n = 29) of respondents stated they would always reject ethically uncertain articles submitted for publication on ethical grounds alone. 12% (n = 4) of respondents stated they would approach each submission on a case-by-case basis. 3% (n = 1) stated they would be likely to publish such research, but only with accompanying editorial. Only 38% (n = 13) give reviewers explicit instruction to reject submissions on ethical grounds if found wanting. Conclusions: Editorial compliance with the Declaration of Helsinki in rejecting research that is conducted unethically was difficult to ascertain because of a poor response rate despite multiple attempts using different modalities. Of those who did respond, the majority do reject ethically suspect research but few explicitly advise reviewers to do so. In this study editors did not take advantage of the opportunity to describe their support for the rejection of the publication of unethical research. © 2012 Angelski et al; licensee BioMed Central Ltd.


Saint-Jacques N.,Surveillance and Epidemiology Unit | Saint-Jacques N.,Dalhousie University | Parker L.,Dalhousie University | Brown P.,University of Toronto | Dummer T.J.,Dalhousie University
Environmental Health: A Global Access Science Source | Year: 2014

Background: Arsenic in drinking water is a public health issue affecting hundreds of millions of people worldwide. This review summarizes 30 years of epidemiological studies on arsenic exposure in drinking water and the risk of bladder or kidney cancer, quantifying these risks using a meta-analytical framework. Methods. Forty studies met the selection criteria. Seventeen provided point estimates of arsenic concentrations in drinking water and were used in a meta-analysis of bladder cancer incidence (7 studies) and mortality (10 studies) and kidney cancer mortality (2 studies). Risk estimates for incidence and mortality were analyzed separately using Generalized Linear Models. Predicted risks for bladder cancer incidence were estimated at 10, 50 and 150 μg/L arsenic in drinking water. Bootstrap randomizations were used to assess robustness of effect size. Results: Twenty-eight studies observed an association between arsenic in drinking water and bladder cancer. Ten studies showed an association with kidney cancer, although of lower magnitude than that for bladder cancer. The meta-analyses showed the predicted risks for bladder cancer incidence were 2.7 [1.2-4.1]; 4.2 [2.1-6.3] and; 5.8 [2.9-8.7] for drinking water arsenic levels of 10, 50, and 150 μg/L, respectively. Bootstrapped randomizations confirmed this increased risk, but, lowering the effect size to 1.4 [0.35-4.0], 2.3 [0.59-6.4], and 3.1 [0.80-8.9]. The latter suggests that with exposures to 50 μg/L, there was an 83% probability for elevated incidence of bladder cancer; and a 74% probability for elevated mortality. For both bladder and kidney cancers, mortality rates at 150 ug/L were about 30% greater than those at 10 μg/L. Conclusion: Arsenic in drinking water is associated with an increased risk of bladder and kidney cancers, although at lower levels (<150 μg/L), there is uncertainty due to the increased likelihood of exposure misclassification at the lower end of the exposure curve. Meta-analyses suggest exposure to 10 μg/L of arsenic in drinking water may double the risk of bladder cancer, or at the very least, increase it by about 40%. With the large number of people exposed to these arsenic concentrations worldwide the public health consequences of arsenic in drinking water are substantial. © 2014 Saint-Jacques et al.; licensee BioMed Central Ltd.


Lethbridge L.,Dalhousie University | Johnston G.M.,Dalhousie University | Johnston G.M.,Surveillance and Epidemiology Unit | Turnbull G.,Dalhousie University
Progress in Palliative Care | Year: 2013

Introduction: Disease interactions can alter functional decline near the end of life (EOL). Parkinson's disease (PD) is characterized by frequent occurrences of co-morbidities but data challenges have limited studies investigating co-morbidities across a broad range of diseases. The goal of this study was to describe disease associations with PD. Methods: We conducted an analysis of death certificate data from 1998 to 2005 in Nova Scotia. All death causes were utilized to select individuals dying of PD and compare with the general population and an age-sex-matched sample without PD. We calculated the mean number of death causes and frequency of disease co-occurrence. To account for the chance occurrence of co-morbidities and measure the strength of association, observed to expected ratios were calculated. Results: PD decedents had a higher mean number of death causes (3.37) than the general population (2.77) and age-sex-matched sample (2.88). Cancer was the most common cause in the population and matched sample but fifth for those with PD. Cancer was one of nine diseases that occurred less often than what would be expected by chance while four were not correlated with PD. Dementia and pneumonia occurred with PD 2.53 ([CI] 2.21-2.85) and 1.83 (CI 1.58-2.08) times more often than expected. The strength of association for both is reduced but remains statistically significant when controlling for age and sex. Discussion: Those with PD have a higher number of co-morbidities even after controlling for age and sex. Individuals dying with PD are more likely to have dementia and pneumonia, which has implications for the provision of care at EOL. © W. S. Maney & Son Ltd 2013.


Porter G.A.,Dalhousie University | Porter G.A.,Cancer Outcomes Research Program | Urquhart R.,Cancer Outcomes Research Program | Bu J.,Cancer Outcomes Research Program | And 5 more authors.
Annals of Surgical Oncology | Year: 2012

Background. Adequate nodal harvest (≥12 lymph nodes) in colorectal cancer has been shown to optimize staging and has been proposed as a quality indicator of colorectal cancer care. We previously demonstrated a population-based improvement in adequate nodal harvest over time, particularly with the use of an audit and feedback strategy. The goal of this current study is to evaluate the impact of improved adequate nodal harvest on 3 relevant clinical outcomes: node positivity rate, use of adjuvant chemotherapy, and survival. Methods. This current population-based study included all patients undergoing resection for primary stage I-III colorectal cancer in Nova Scotia, Canada, from January 1, 2001 to December 31, 2005. Linkage of the provincial cancer registry with other administrative databases (hospital discharge data, physician claims data, and national census data) provided clinical, demographic, diagnostic, treatment event, and survival data. The association between increase in adequate node harvest and relevant clinical outcomes was examined for all patients and in a subgroup analysis of patients who received care in a health district that used audit and feedback to improve nodal harvest. Results. Among the 2,250 patients, the median nodal harvest was 8, and the overall node positive rate was 35.9%. Despite significant improvement in the proportion of patients undergoing adequate nodal harvest over time (P < .0001), no significant change was observed in the node positivity rate (P = .51), proportion of patients undergoing adjuvant chemotherapy (P = .83), or survival (P = .25). In the subgroup analysis confined to patients where audit and feedback was used to improve nodal harvest rates, clinical outcomes were not improved. Conclusions. Although improvements in the rate of adequate nodal harvest did occur over time, no corresponding meaningful improvement in clinical outcomes was noted. Given the need that quality indicators not only be associated with outcome, but also that outcome improves as such indicators are optimized, this study questions the inclusion of a nodal harvest ≥12 lymph nodes as a quality indicator of colorectal cancer care. © Society of Surgical Oncology 2011.


PubMed | University of British Columbia, University of Toronto, Surveillance and Epidemiology Unit and Dalhousie University
Type: | Journal: BMC public health | Year: 2016

Bladder and kidney cancers are the ninth and twelfth most common type of cancer worldwide, respectively. Internationally, rates vary ten-fold, with several countries showing rising incidence. This study describes the spatial and spatio-temporal variations in the incidence risk of these diseases for Nova Scotia, a province located in Atlantic Canada, where rates for bladder and kidney cancer exceed those of the national average by about 25% and 35%, respectively.Cancer incidence in the 311 Communities of Nova-Scotia was analyzed with a spatial autoregressive model for the case counts of bladder and kidney cancers (3,232 and 2,143 total cases, respectively), accounting for each Communitys population and including variables known to influence risk. A spatially-continuous analysis, using a geostatistical Local Expectation-Maximization smoothing algorithm, modeled finer-scale spatial variation in risk for south-western Nova Scotia (1,810 bladder and 957 kidney cases) and Cape Breton (1,101 bladder, 703 kidney).Evidence of spatial variations in the risk of bladder and kidney cancer was demonstrated using both aggregated Community-level mapping and continuous-grid based localized mapping; and these were generally stable over time. The Community-level analysis suggested that much of this heterogeneity was not accounted for by known explanatory variables. There appears to be a north-east to south-west increasing gradient with a number of south-western Communities have risk of bladder or kidney cancer more than 10% above the provincial average. Kidney cancer risk was also elevated in various northeastern communities. Over a 12 year period this exceedance translated in an excess of 200 cases. Patterns of variations in risk obtained from the spatially continuous smoothing analysis generally mirrored those from the Community-level autoregressive model, although these more localized risk estimates resulted in a larger spatial extent for which risk is likely to be elevated.Modelling the spatio-temporal distribution of disease risk enabled the quantification of risk relative to expected background levels and the identification of high risk areas. It also permitted the determination of the relative stability of the observed patterns over time and in this study, pointed to excess risk potentially driven by exposure to risk factors that act in a sustained manner over time.


PubMed | Ryerson University, University of Toronto, Surveillance and Epidemiology Unit and Prevention and Cancer Control
Type: Journal Article | Journal: PloS one | Year: 2015

It has been suggested that the association between shift work and chronic disease is mediated by an increase in obesity. However, investigations of the relationship between shift work and obesity reveal mixed findings. Using a recently developed exposure assessment tool, this study examined the association between shift work and obesity among Canadian women from two studies: a cohort of university alumni, and a population-based study.Self-administered questionnaire data were used from healthy, currently employed females in a population-based study, the Ontario Womens Diet and Health case-control study (n = 1611 controls), and from a subset of a of university alumni from the Canadian Study of Diet, Lifestyle, and Health (n = 1097) cohort study. Overweight was defined as BMI25 to <30, and obesity as BMI30. Reported occupation was converted to occupational codes and linked to a probability of shift work value derived from Survey of Labour and Income Dynamics data. Regular evenings, nights, or rotating work comprised shift work. Polytomous logistic regression estimated the association between probability of shift work, categorized as near nil, low, medium, and high probability of shift work, on overweight and obesity, controlling for detected confounders.In the population-based sample, high probability of shift work was associated with obesity (reference = near nil probability of shift work, OR: 1.88, 95% CI: 1.01-3.51, p = 0.047). In the alumni cohort, no significant association was detected between shift work and overweight or obesity.As these analyses found a positive association between high probability of shift work exposure and obesity in a population-based sample, but not in an alumni cohort, it is suggested that the relationship between shift work and obesity is complex, and may be particularly susceptible to occupational and education-related factors within a given population.

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