Cancer incidence, mortality, and stage at diagnosis in First Nations living in Manitoba

BACKGROUND

In the present study, we examined breast (bca) and colorectal cancer (crc) incidence and mortality and stage at diagnosis for First Nations (fn) individuals and all other Manitobans (aoms).

METHODS

Several population-based databases were linked to determine ethnicity and to calculate age-standardized incidence and mortality rates. Logistic regression was used to compare bca and crc stage at diagnosis.

RESULTS

From 1984-1988 to 2004-2008, the incidence of bca increased for fn and aom women. Breast cancer mortality increased for fn women and decreased for aom women. First Nations women were significantly more likely than aom women to be diagnosed at stages iii-iv than at stage i [odds ratio (or) for women ≤50 years of age: 3.11; 95% confidence limits (cl): 1.20, 8.06; or for women 50-69 years of age: 1.72; 95% cl: 1.03, 2.88). The incidence and mortality of crc increased for fn individuals, but decreased for aoms. First Nations status was not significantly associated with crc stage at diagnosis (or for stages i-ii compared with stages iii-iv: 0.98; 95% cl: 0.68, 1.41; or for stages i-iii compared with stage iv: 0.91; 95% cl: 0.59, 1.40).

CONCLUSIONS

Our results underscore the need for improved cancer screening participation and targeted initiatives that emphasis collaboration with fn communities to reduce barriers to screening and to promote healthy lifestyles.

Distribution of human papillomavirus types, cervical cancer screening history, and risk factors for infection in Manitoba

OBJECTIVES

We conducted a study to investigate the prevalence of human papillomavirus (HPV) infections in an opportunistic sample of women in Manitoba, Canada. We inquired about risk factors associated with HPV infections and linked the HPV typing results with the cervical cancer screening history of the participants.

METHODS

The study population included 592 women attending Papanicolaou (Pap) test clinics. After signing a consent form, participants were given a self-administered questionnaire on risk factors and received a conventional Pap test. Residual cells from the Pap tests were collected and sent for HPV typing.

RESULTS

The mean age of the population was 43 years. A total of 115 participants (19.4%) had an HPV infection, 89 of whom had a normal Pap test. Of those who were HPV-positive, 61 (10.3%) had high-risk (Group 1) HPV. HPV-16 was the most prevalent type (15/115: 13.0% of infections). The most consistent risk factors for HPV infection were young age, Aboriginal ethnicity, higher lifetime number of sexual partners and higher number of sexual partners in the previous year.

CONCLUSION

The prevalence of HPV types in Manitoba is consistent with the distributions reported in other jurisdictions. These data provide baseline information on type-specific HPV prevalence in an unvaccinated population and can be useful in evaluating the effectiveness of the HPV immunization program. An added benefit is in the validation of a proof of concept which links a population-based Pap registry to laboratory test results and a risk behaviour survey to assess early and late outcomes of HPV infection. This methodology could be applied to other jurisdictions across Canada where such capacities exist.

Risks of second primary cancer among patients with major histological types of lung cancers in both men and women

BACKGROUND

Patterns of second primary cancers (SPCs) following first primary lung cancers (FPLCs) may provide aetiological insights into FPLC.

METHODS

Cases of FPLCs in 13 cancer registries in Europe, Australia, Canada, and Singapore were followed up from the date of FPLC diagnosis to the date of SPC diagnosis, date of death, or end of follow-up. Standardised incidence ratios (SIRs) were calculated to estimate the magnitude of SPC development following squamous cell carcinoma (SCC), small cell lung carcinoma (SCLC), and adenocarcinoma (ADC).

RESULTS

Among SCC patients, male SIR=1.58 (95% confidence interval (CI)=1.50-1.66) and female SIR=2.31 (1.94-2.72) for smoking-related SPC. Among SCLC patients, the respective ratios were 1.39 (1.20-1.60) and 2.28 (1.73-2.95), and among ADC patients, they were 1.73 (1.57-1.90) and 2.24 (1.91-2.61). We also observed associations between first primary lung ADC and second primary breast cancer in women (SIR=1.25, 95% CI=1.05-1.48) and prostate cancer (1.56, 1.39-1.79) in men.

CONCLUSION

The FPLC patients carried excess risks of smoking-related SPCs. An association between first primary lung ADC and second primary breast and ovarian cancer in women at younger age and prostate cancers in men may reflect an aetiological role of hormones in lung ADC.

Long-term mortality following injury in working-age adults: a systematic review

Priorities for prevention activities and planning for services depend on comprehensive knowledge of the distribution of the injury-related burden in the community. The aim of this systematic review was to quantify the effect of being injured, compared with not being injured, on long-term mortality in working age adults. Cohort studies were selected that were population-based, measured mortality post-discharge from inpatient treatment, included a non-injured comparison group and related to working-age adults. Data synthesis was in tabular and text form with a meta-analysis not being possible because of the heterogeneity between studies. Eleven studies met the inclusion criteria. All studies found an overall positive association between injury and increased mortality. While the greatest excess mortality was evident during the initial period post-injury, increased mortality was shown in some studies to persist for up to 40 years after injury. Due to the limited number of injury types studied and heterogeneity between studies, there is insufficient published evidence on which to calculate population estimates of long-term mortality, where injury is a component cause. The review does suggest there is considerable excess mortality following injury that is not accounted for in current methods of quantifying injury burden, and is not used to assess quality and effectiveness of trauma care.

Ten-year health service use outcomes in a population-based cohort of 21,000 injured adults: the Manitoba injury outcome study

OBJECTIVE

To quantify long-term health service use (HSU) following non-fatal injury in adults.

METHODS

A retrospective, population-based, matched cohort study identified an inception cohort (1988-91) of injured people who had been hospitalized (ICD-9-CM 800-995) aged 18-64 years (n = 21 032) and a matched non-injured comparison group (n = 21 032) from linked administrative data from Manitoba, Canada. HSU data (on hospitalizations, cumulative length of stay, physician claims and placements in extended care services) were obtained for the 12 months before and 10 years after the injury. Negative binomial and Poisson regressions were used to quantify associations between injury and long-term HSU.

FINDINGS

Statistically significant differences in the rates of HSU existed between the injured and non-injured cohorts for the pre-injury year and every year of the follow-up period. After controlling for pre-injury HSU, the attributable risk percentage indicated that 38.7% of all post-injury hospitalizations (n = 25 183), 68.9% of all years spent in hospital (n = 1031), 21.9% of physician claims (n = 269 318) and 77.1% of the care home placements (n = 189) in the injured cohort could be attributed to being injured.

CONCLUSION

Many people who survive the initial period following injury, face long periods of inpatient care (and frequent readmissions), high levels of contact with physicians and an increased risk of premature placement in institutional care. Population estimates of the burden of injury could be refined by including long-term non-fatal health consequences and controlling for the effect of pre-injury comorbidity.

Long term health outcomes after injury in working age adults: a systematic review

BACKGROUND

Estimating the contribution of non-fatal injury outcomes remains a considerable challenge and is one of the most difficult components of burden of disease analysis. The aim of this systematic review was to quantify the effect of being injured compared with not being injured on morbidity and health service use (HSU) in working age adults.

METHODS

Studies were selected that were population based, had long term health outcomes measured, included a non-injured comparison group, and related to working age adults. Meta-analysis was not attempted because of the heterogeneity between studies.

RESULTS

Nine studies met the inclusion criteria. In general, studies found an overall positive association between injury and increased HSU, exceeding that of the general population, which in some studies persisted for up to 50 years after injury. Disease outcome studies after injury were less consistent, with null findings reported.

CONCLUSION

Because of the limited injury types studied and heterogeneity between study outcome measures and follow up, there is insufficient published evidence on which to calculate population estimates of long term morbidity, where injury is a component cause. However, the review does suggest injured people have an increased risk of long term HSU that is not accounted for in current methods of quantifying injury burden.

Indicators of injury burden: Which types are the most important?

Injury indicators are used for monitoring the impact of injury prevention initiatives on the population burden of injury. The object of the present study was to identify the types of injury responsible for the major component of the population health burden of injury in a large cohort in Manitoba, Canada. Injury cases (ICD-9-CM 800-995) aged 18-64 years were identified from all Manitoba hospital data between 1988 and 1991. Morbidity data were obtained from hospital discharge abstracts 12 months prior to date of injury and for 12 months post-injury. Outcomes for individuals were calculated as the difference pre- and post-injury in hospital inpatient days. Death outcomes in the 12 months post-injury were obtained by linking the cohort with the population registry. Summed outcomes across the population were stratified into injury types based on the International Code of Diseases (ICD) code of the index injury. Outcomes were also stratified by injury severity score categories where the injury severity score was obtained using ICDMAP-90. When ranked by contribution to the cohort's cumulative hospital inpatient days in the 12 months post-injury, the six most common ICD subchapter groups accounted for 65% of the total inpatient days. These six injury types also accounted for 62% of the total number of deaths in this cohort in 12 months after injury. The suggested injury types to use as indicators of burden include fracture of the lower limb, fracture of the head and neck, poisonings, intracranial injury, fracture of the upper limb, and fracture of skull.

How well do anatomical-based injury severity scores predict health service use in the 12 months after injury?

There is an acknowledged need for valid and reliable injury scores, suitable for use at the population level, which can accurately predict the long-term outcome of injury. The objective was to quantify the extent to which the abbreviated injury severity score (AIS) and the functional capacity index score (FCI) predict use of health services in the 12 months following an injury event. A cohort of injured people (ICD-9-CM 800-995) aged 18 - 64 years was identified from Manitoba hospital discharge abstracts from January 1988 to December 1991. For each member of the cohort whose injuries could be mapped to an abbreviated injury scale unique identifier, a maximum AIS (maxAIS) and a maximum FCI (maxFCI) were obtained. The cohort was linked with hospital discharge abstracts, physicians' claims and deaths from the population registry for the 12 months following injury. Negative binomial regression was used to model the relationships between the severity scores and the three outcome measures, while controlling for potential confounding variables. In total, 20 677 (97%) eligible cases were identified, of which 16 834 (81%) could be assigned a maxAIS and 15 823 (77%) a maxFCI. MaxAIS and maxFCI were significantly associated with total days in hospital following injury, but explained little of the variation in any of the health service use outcome variables (maxAIS, partial pseudo r2 ranging from < 0.001 to 0.041; and maxFCI, partial pseudo r2 ranging from < 0.001 to 0.018). It was concluded that anatomical damage is only partly responsible for long-term injury outcome. Additional variables would need to be included in predictive models of health outcomes of injury before these models could be reliable.

Second primary cancers among 109 000 cases of non-Hodgkin's lymphoma

An analysis of other primary cancers in individuals with non-Hodgkin's lymphoma (NHL) can help to elucidate this cancer aetiology. In all, 109 451 first primary NHL were included in a pooled analysis of 13 cancer registries. The observed numbers of second cancers were compared to the expected numbers derived from the age-, sex-, calendar period- and registry-specific incidence rates. We also calculated the standardised incidence ratios for NHL as a second primary after other cancers. There was a 47% (95% confidence interval 43–51%) overall increase in the risk of a primary cancer after NHL. A strongly significant (P<0.001) increase was observed for cancers of the lip, tongue, oropharynx^*, stomach, small intestine, colon^*, liver, nasal cavity^*, lung, soft tissues^*, skin melanoma^*, nonmelanoma skin^*, bladder^*, kidney^*, thyroid^*, Hodgkin's lymphoma^*, lymphoid leukaemia^* and myeloid leukaemia. Non-Hodgkin's lymphoma as a second primary was increased after cancers marked with an asterisk. Patterns of risk indicate a treatment effect for lung, bladder, stomach, Hodgkin's lymphoma and myeloid leukaemia. Common risk factors may be involved for cancers of the lung, bladder, nasal cavity and for soft tissues, such as pesticides. Bidirectional effects for several cancer sites of potential viral origin argue strongly for a role for immune suppression in NHL.

Long-term mortality following trauma: 10 year follow-up in a population-based sample of injured adults

BACKGROUND

The aim of the study was to quantify trauma-related mortality in injured adults over 10 years postinjury.

METHODS

A population-based matched cohort study used linked administrative data from Manitoba, Canada, to identify an inception cohort (1988-1991) of hospitalized trauma cases (ICD-9-CM 800-959.9) aged 18-64 years (n = 18,210) and a matched noninjured comparison group (n = 18,210). Mortality outcomes were obtained by linking the two cohorts with the Manitoba Population Registry for a period of 10 years postinjury.

RESULTS

The adjusted all-cause mortality rate ratio (MRR) was 7.29 (95% CI 4.53-11.74) for the 60 days immediately postinjury. The MRRs ranged between 1.17 and 2.41 for the remainder of the 10 year follow-up period. The index injury was estimated to be responsible for 41% of all recorded deaths in the injured cohort.

CONCLUSIONS

Estimates of the total mortality burden, based on the early inpatient period alone, substantially underestimates the true burden from injury.

Second primary malignancies in patients with male breast cancer

An international multicentre study of first and second primary neoplasms associated with male breast cancer was carried out by pooling data from 13 cancer registries. Among a total of 3409 men with primary breast cancer, 426 (12.5%) developed a second neoplasia; other than breast cancer, a 34% overall excess risk of second primary neoplasia, affecting the small intestine (standardised incidence ratio, 4.95, 95% confidence interval, 1.35–12.7), rectum (1.78, 1.20–2.54), pancreas (1.93, 1.14–3.05), skin (nonmelanoma, 1.65, 1.16–2.29), prostate (1.61, 1.34–1.93) and lymphohaematopoietic system (1.63, 1.12–2.29). A total of 225 male breast cancers was recorded after cancers other than breast cancer, but an increase was found only after lymphohaematopoietic neoplasms. BRCA2 (and to some extent BRCA1) mutations may explain the findings for pancreatic and prostate cancers. Increases at other sites may be related to unknown factors or to chance. This large study shows that the risks for second discordant tumours after male breast cancer pose only a moderate excess risk.

Cyanobacterial (blue-green algae) contamination in drinking water and perinatal outcomes

OBJECTIVE

The aim of this ecological study was to examine the relationship between potential cyanobacterial exposure through drinking water during pregnancy and birth outcomes.

METHOD

One hundred and fifty-six communities in South-Eastern Australia were involved, providing 32,700 singleton live newborn during the period 1992-94. Cyanobacterial occurrence and cell density (alert level) in drinking water sources during the first trimester, the total gestational period for premature births or limited to 36 weeks in term infants, and the last 12 weeks prior to preterm births or up to and including 36 weeks in term infants were used as estimates of exposure.

RESULTS

There were statistically significant differences between the proportion of time during the first trimester with cyanobacterial occurrence and the percentage of births that were low birth weight (LBW) and very low birth rate (VLBW). Significant differences were also found among various categories of first trimester exposure based on average cell density and LBW, prematurity and congenital defects. However, the pattern of these results does not suggest a causal link to cyanobacteria. There were no clear dose-response relationships. Analyses based on exposure during the last 12 weeks and total gestation also showed no significant dose-response effects.

CONCLUSION

The results of this study provide no clear evidence for an association between cyanobacterial contamination of drinking water sources and adverse pregnancy outcomes.

Benign prostatic hyperplasia morbidity and mortality among immigrants in Australia and Canada

Previous studies have suggested that the risk of benign prostatic hyperplasia (BPH) varies among racial and ethnic groups. However, these studies have tended to be anecdotal or based on crude proportions or rates. This study describes the age-standardized BPH hospitalization (1985-1987) and mortality (1984-1988) rates (SMRs) for numerous immigrant groups in Australia and Canada. The SMRs for some of the immigrants were compared with those in the origin countries. Both the BPH hospitalization and mortality rates varied markedly among immigrant groups. The most consistent findings were the low rates of Italians and Asians. Relative to the origin country SMRs, the SMRs for the majority of immigrant groups shifted towards the destination native-born rate. This convergence probably resulted from more standard procedures of BPH ascertainment and cause of death recording within a country than between countries, and possibly, from convergence in risk factor levels.

Breast cancer mortality among immigrants in Australia and Canada

BACKGROUND

By moving between geographic regions with differing levels of breast cancer risk, migrant populations of women provide a unique opportunity to examine the impact of exposure to new environments and lifestyles on breast cancer risk. Breast cancer incidence and mortality rates for the majority of migrant groups originating from countries with low breast cancer risk have been found to increase toward the rates observed in destination countries with populations at higher risk for this disease. Because very little information exists on migrants from high- to low-risk countries, it is not known whether rates for these groups decrease or whether migrant groups generally experience increases in breast cancer rates.

PURPOSE

To address these questions, we determined the breast cancer mortality rates for women from both lower and higher risk countries who had immigrated to Australia and Canada and compared these rates with those exhibited by the population in the origin country and by the destination native-born population.

METHODS

Individual mortality records covering the years 1984 through 1988 and 1986 census data for Australia and Canada were obtained. Direct age-standardized mortality rates and rate ratios (and their 95% confidence intervals) were calculated for immigrant groups in Australia and Canada. Age-standardized rate ratios by length of residence in Australia were calculated. Weighted regression analyses of observed and expected mortality changes were performed.

RESULTS

In Australia, the mortality rates for 12 (75%) of 16 immigrant groups from lower risk countries and 10 (71.4%) of 14 groups from higher risk countries shifted toward the rate of native-born Australians. In Canada, the rates for 12 (60%) of 20 immigrant groups from lower risk countries and four (80%) of five groups from higher risk countries converged to the rate of native-born Canadians. Overall, the extent of convergence (shift of immigrant's mortality rate in origin country toward rate of native-born population) was 50% for immigrants in Australia and 38% for immigrants in Canada. Although there was not a consistent pattern of convergence with length of residence in Australia, after 30 or more years, the mortality rates of 15 (83.3%) of 18 immigrant groups had shifted toward the rate of the native-born Australians. Because of the small number of deaths in many of the immigrant groups studied, the observed differences in the breast cancer mortality age-standardized rates between the origin country and immigrant group, although often substantial, were seldom statistically significant.

CONCLUSIONS

Breast cancer mortality rates among women in the majority of immigrant groups shifted from the rate observed in their country of origin toward the rate of the native-born population in the destination country.

IMPLICATIONS

These findings indicate that environmental and lifestyle factors associated with the new place of residence influence the breast cancer rates of immigrants and also suggest that, since most migrants migrate as adults, the risk of breast cancer can be altered in later life.

Ovarian cancer mortality among immigrants in Australia and Canada

This study examined the impact of changing environments on ovarian cancer by comparing age-standardized mortality rates of numerous immigrants groups in Australia and Canada to those in the origin countries for the period 1984-1988. Mortality rates by length of residence in Australia (0-29 and 30+ years) were also calculated. In Australia, the mortality rates for all four immigrant groups from low-risk countries and 53.8% from high-risk countries (n = 13) shifted toward the rate of the native-born Australians. In Canada, rates for 88.9% of immigrant groups from low-risk countries (n = 9) and 30.0% from high-risk countries (n = 10) converged to the rate of native-born Canadians. Among individual immigrant groups there was not a consistent pattern of convergence with length of residence in Australia. There was evidence of convergence among the long-term residents of some of the groups and in the aggregate analysis. The increased mortality among the majority of immigrant groups is consistent with the reported inverse relationship between parity and ovarian cancer and the generally lower parity of immigrant women compared to those in their home country. The period of residence and analyses suggests that long-term environmental and lifestyle factors in the new place of residence may also influence ovarian cancer mortality.

Estimating standardized mortality odds ratios with national mortality followback data

Proportionate mortality analyses are often used to study cause-specific mortality when population denominators are not available. The purpose of this paper is to present an extension of published proportionate mortality ratio logistic regression methods used to analyze such data. This paper describes methods used to estimate standardized mortality odds ratios (SMORs) with numerator data and the problems encountered when external standard rates are not available for all strata of interest. This paper focuses on the case where one has representative mortality followback data. These data are based on a large, representative sample of deaths from a defined population for whom numerous covariates about the decedents are collected from surviving family members. With these data, one may use logistic regression methods to generate fully standardized estimates of risk, SMORs, with numerator data. It is also possible to generate SMORs that allow for effect modification. Mortality followback data are also a more flexible data source from which one may generate substitutes for external standard mortality rate ratios to be used with previously developed SMOR methods. An application of the methods is provided using logistic regression.

Homicide victims among Australian immigrants

The homicide rates for various immigrant groups in Australia were calculated, and the influence of the rate in countries of origin on immigrant rates and the relationship between the birthplace of the accused and victim were examined. Age-sex standardised mortality ratios (SMRs) for homicide were calculated for the immigrant groups, based on 1984-1988 mortality data and 1986 census data. The Australian-born homicide rates were used as the standard. Standardised mortality ratios for countries of origin were derived from WHO data. A cross-tabulation of the birthplaces of the accused and the victim was compiled from 1989-1992 police records. Male SMRs ranged from 0.13 (P < 0.01) for immigrants from Africa and the Americas to 5.83 (P < 0.05) for Koreans. Several female groups had lower SMRs than the Australian-born, although none of these differences were significant. Indonesian females had the highest SMR (5.32, P < 0.01). There was a positive Spearman correlation between the ranking of homicide rates for the origin populations and the immigrants (males 0.64, P < 0.05; females 0.62, P < 0.05). Overall, 51.3 per cent of immigrants were killed by their compatriots. This ranged from zero for New Zealanders to 100 per cent for immigrants from the Middle East. In order to further identify factors contributing to the large differences in rates it is imperative to have information on the victim, the perpetrator and the circumstances surrounding the murder.

Stillbirths, neonatal and post-neonatal mortality by race, birthweight and gestational age

The birthweight and gestational age specific mortality of singleton Aboriginal and White infants born in Western Australia during the period 1980-86 is described. The analyses are based on the approximately 8000 Aboriginal and 143,000 White births notified through the Western Australia Midwives' system, which were linked to perinatal and infant death records. Overall, stillbirth, neonatal and post-neonatal mortality risks were significantly higher (P < 0.01) for Aboriginals than Whites. However, for specific birthweights and gestational ages, particularly for infants of lower birthweight and shorter gestations, Aboriginals had lower mortality risks than Whites. The ratio of Aboriginal to White mortality risks tended to increase with advancing age of death, suggesting that longer exposure to the well-documented poorer social and environmental conditions of Aboriginal infants increased the mortality risk.

Influence of migrants on regional variations of stomach and colon cancer mortality in the Western United States

In order to examine the impact of migrants on regional variations in stomach and colon cancer, standardized mortality ratios (SMRs) were calculated for the total, nonmigrant (born and dying in same state), and migrant (born out of state) White residents of each of the 11 western states in the United States (US). The SMRs were derived from the National Center for Health Statistics' Mortality Detail Files for 1979-1981 and the 1980 Census Public Use Microdata 5-Percent Sample tapes. Migrants in the western US accounted for 79% of all stomach and colon cancer deaths. There was no consistent relationship between the SMRs of migrants and nonmigrants, with the migrant SMRs being higher in some states and lower in others. As a consequence of this differential impact, and their substantial numbers, migrants obscured the underlying regional patterns of mortality risk observed in the nonmigrants. The states of high or low risk were more contiguous in the analysis based on nonmigrants than the total population, and the interstate ranges in mortality were greater for nonmigrants. In areas with high in-migration, mortality atlases based on the total population may give an inaccurate portrayal of regional mortality risks, and spurious correlations may arise between the distributions of diseases and environmental characteristics of the regions. Regional mortality patterns of nonmigrants may more precisely reflect the factors which are influencing these cancers and thus provide a greater potential in providing clues to their aetiologies.

Aboriginal and white births in Western Australia, 1980-1986. Part I: Birthweight and gestational age

This article describes the distributions of birthweight and gestational age of all singleton Aboriginal and white live-born infants in Western Australia for the period 1980-1986. At early gestational ages, the mean birthweight was greater for Aboriginal infants. However, after 34-weeks' gestation for male infants and 32-weeks' gestation for female infants, the pattern was reversed. More Aboriginal infants were of low birthweight--male Aboriginal infants, 9.8%; male white infants, 4.0%; female Aboriginal infants, 12.4%; and female white infants, 4.6%, this excess only occurred in term (37- to 41-weeks' gestation) and post-term (42- to 52-weeks' gestation) infants. The birthweight distributions for Aboriginal and white infants were similar in preterm infants, but at term and beyond Aboriginal infants tended to be lighter. Preterm (fewer than 37-weeks' gestation) births were more common among Aborigines (male Aboriginal infants, 16.0%; white male infants, 6.8%; female Aboriginal infants, 15.9%; and female white infants, 6.0%). Thus, it seems that the distributions of both birthweight and gestational age in Aboriginal infants are shifted downward compared with those for white infants. Aboriginal infants normally may be smaller and more likely to be born earlier than are white infants as well as having a definite shift towards pathological growth retardation at term and beyond.

Convergence of immigrant suicide rates to those in the destination country

Factors influencing the 1969-1973 suicide rate in 25 immigrant groups in Canada were investigated. Standardized mortality ratios (SMRs) were calculated for each group relative to the suicide rates in the origin country populations. Compared with their origin countries, immigrant females exhibited a significant increase in suicide rates (SMR = 1.11, p less than 0.01), whereas immigrant males did not (SMR = 0.98). Another set of standardized mortality ratios were then calculated for both origin and immigrant populations using the Canadian native-born rates as the standard. For the majority of immigrant groups, the standardized mortality ratios were significantly different from the ratios of their corresponding origin country populations, with 60% of the female immigrant groups and 41% of the male immigrant groups exhibiting higher ratios. Considerable variation was observed in the immigrant standardized mortality ratios, with a significant proportion of this variability being associated with the suicide rates in the origin countries (males r = 0.60, p less than 0.01; females r = 0.47, p less than 0.05). Using the standardized mortality ratios based on the Canadian native-born rates, the degree of "convergence" of immigrant suicide rates to the Canadian native-born rates was examined. Overall, significant convergence occurred for both sexes (p less than 0.01), with the immigrant suicide rates converging 40% of the initial difference between the standardized mortality ratios for the origin country and the Canadian native-born.