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Canadian immigrants have lower overall cancer risk than the Canadian-born population. Less is known about risks for immigrant subgroups and site-specific cancers. Linked administrative data sets were used to compare cancer incidence between subgroups of immigrants to Canada and the general Canadian population. The study involved 128,962 refugees and 241,010 non-refugees. Standardized incidence ratios (SIRs) were calculated for all-site and site-specific cancers by immigration categories and regions of birth. Relative to the general Canadian population, incidence of all-site cancer was lower among immigrants overall, by sex and refugee status (non-refugee SIRs 0.25: men, 0.24: women; refugee SIRs 0.31: both). Significantly higher SIRs resulted for liver, nasopharyngeal and cervical cancers, including liver cancer among South-East Asian and North-East Asian immigrants, and nasopharyngeal cancer among North-East Asian non-refugees. Hypothesized explanations for variation in cancer incidence include earlier viral infection in the country of origin.

There is concern among Aboriginal communities in Canada that conventional approaches to the treatment of diabetes are ineffective in part because they fail to recognize the local Aboriginal perspective on the causal determinants of diabetes. While this shortcoming has been recognized, there have been no explicit attempts to practically define these perspectives and prescribe how conventional health management might be altered to incorporate them. In part, this may be due to difficulties in communicating Aboriginal perspectives in a manner which permits incorporation into conventional science-based frameworks. Here we use fuzzy cognitive mapping (FCM) as a technique to represent and compare Canadian Aboriginal and conventional science perspectives on the determinants of diabetes as contained in published articles drawn from a search of Medline and PubMed (1966-2005). The FCM allows for a detailed description of the complex system of culture, spirituality and balance at the root of the Aboriginal view. It also highlights how, for these less tangible factors, it is possible to identify more concrete stressors and outcomes which are amenable to management and monitoring. This preliminary comparison of conventional and Aboriginal views also demonstrates the potential for FCM as a technique to extract, compare and integrate perspectives of different knowledge systems into health management and policy development.

Background: Previously, the mortality was reported in a cohort of male workers at an Ontario chemical plant., Aims: To expand the cohort and to investigate the mortality and cancer incidence risk among chemical manufacturing sites., Methods: We followed 5277 men and 1301 women from 1950 to 1999., Results: Employees experienced lower mortality and cancer incidence rates than the general population for several major causes of death, including heart disease, respiratory cancer and many other cancers. There were no cases of angiosarcoma of the liver. We observed a lower mortality rate of prostate cancer [standardized mortality ratio = 0.79, 95% confidence interval (CI) 0.43-1.32], but a higher incidence rate of prostate cancer [standardized incidence ratio (SIR) = 1.22, 95% CI 1.00-1.48]. Among the Sarnia employees, the incidence of pleural neoplasms was increased (5 observed versus 1.48 expected, SIR = 3.37, 95% CI 1.09-7.86). These cancers were included in the 12 deaths with malignant mesothelioma at Sarnia., Conclusion: Consistent with the earlier report, lower mortality rates were observed for the major classifications of disease and malignant neoplasms. The higher incidence rates of prostate cancer are not readily explainable but may reflect increased screening among current employees and recent retirees. Past asbestos exposure prior to 1980 is probably a contributor to the deaths due to malignant mesothelioma but is not reflected in lung cancer mortality. We find little indication of any other increased rates of mortality or cancer within the overall workforce of these chemical plants.

This study examines mortality patterns among Canadian immigrants, including both refugees and non-refugees, 1980-1998. Records of a stratified random sample of Canadian immigrants landing between 1980-1990 (N = 369,936) were probabilistically linked to mortality data (1980-1998). Mortality rates among immigrants were compared to those of the general Canadian population, stratifying by age, sex, immigration category, region of birth and time in Canada. Multivariate analysis examined mortality risks for various immigrant subgroups. Although immigrants presented lower all-cause mortality than the general Canadian population (SMR between 0.34 and 0.58), some cause-specific mortality rates were elevated among immigrants, including mortality from stroke, diabetes, infectious diseases (AIDS and hepatitis among certain subgroups), and certain cancers (liver and nasopharynx). Mortality rates differed by region of birth, and were higher among refugees than other immigrants. These results support the need to consider the heterogeneity of immigrant populations and vulnerable subgroups when developing targeted interventions.