Cancer incidence in Estonian migrants to Sweden

Increased Incidence and Mortality of Gastric Cancer in Immigrant Populations from High to Low Regions of Incidence: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Gastric cancer is the leading cause of infection-related cancer death and the third-leading cause of cancer death worldwide. The effect of immigration on gastric cancer risk is not well-defined but might be helpful for screening or surveillance endeavors. We performed a systematic review and meta-analysis to define the risk of gastric cancer in immigrants from high-incidence regions to low-incidence regions (including Western Europe, Australia, Brazil, Canada, Israel, and the United States).

METHODS

We searched MEDLINE and EMBASE databases, from January 1980 to January 2019, for studies that identified immigrants from high-incidence regions of gastric cancer, provided clear definitions of immigrant and reference populations, and provided sufficient data to calculate gastric cancer incidence and gastric cancer-related mortality. We performed meta-analyses of standardized incidence ratios (SIR) for first-generation immigrants from high- to low-incidence regions, stratified by immigrant generation, sex, and anatomic and histologic subtype, when data were available.

RESULTS

We identified 38 cohort studies that met our inclusion criteria. All 13 studies of 21 distinct populations reported significantly increased SIRs for gastric cancer in first-generation foreign-born immigrants (men SIR range, 1.24-4.50 and women SIR range, 1.27-5.05). The pooled SIR for immigrants with all types of gastric cancer was 1.66 (95% CI, 1.52-1.80) for men and 1.83 (95% CI, 1.69-1.98) for women. Nine studies from 2 high-incidence populations (the former Soviet Union and Japan) reported an increased gastric cancer standardized mortality ratio in first-generation immigrants who migrated to regions of low incidence (former Soviet Union immigrants, 1.44-1.91 for men and 1.40-2.56 for women).

CONCLUSIONS

Immigrants from regions with a high incidence of gastric cancer to regions of low incidence maintain a higher risk of gastric cancer and related mortality, based on a comprehensive systematic review and meta-analysis. Assessment of immigrant generation along with other risk factors might help identify high-risk populations for prevention and therapeutic interventions.

Breast cancer incidence and case fatality among 4.7 million women in relation to social and ethnic background: a population-based cohort study

INTRODUCTION

Incidence of breast cancer is increasing around the world and it is still the leading cause of cancer mortality in low- and middle-income countries. We utilized Swedish nationwide registers to study breast cancer incidence and case fatality to disentangle the effect of socioeconomic position (SEP) and immigration from the trends in native Swedes.

METHODS

A nation-wide cohort of women in Sweden was followed between 1961 and 2007 and incidence rate ratio (IRR) and hazard ratio (HR) with 95% confidence intervals (CIs) were estimated using Poisson and Cox proportional regression models, respectively.

RESULTS

Incidence continued to increase; however, it remained lower among immigrants (IRR = 0.88, 95% CI = 0.86 to 0.90) but not among immigrants' daughters (IRR = 0.97, 95% CI = 0.94 to 1.01) compared to native Swedes. Case fatality decreased over the last decades and was similar in native Swedes and immigrants. However, case fatality was significantly 14% higher if cancer was diagnosed after age 50 and 20% higher if cancer was diagnosed in the most recent years among immigrants compared with native Swedes. Women with the highest SEP had significantly 20% to 30% higher incidence but had 30% to 40% lower case fatality compared with women with the lowest SEP irrespective of country of birth. Age at immigration and duration of residence significantly modified the incidence and case fatality.

CONCLUSIONS

Disparities found in case fatality among immigrants by age, duration of residence, age at immigration and country of birth emphasize the importance of targeting interventions on women that are not likely to attend screenings or are not likely to adhere to the therapy suggested by physicians. The lower risk of breast cancer among immigrant women calls for more knowledge about how the lifestyle factors in these women differ from those with high risk, so that preventative measures may be implemented.

Does immigration play a role in the risk of gastric cancer by site and by histological type? A study of first-generation immigrants in Sweden

The observed increased risks of gastric cancer among first-generation immigrants compared to those in Swedes suggest the role of childhood environmental exposure in the risk of this disease.

Breast Cancer among Immigrants: A Systematic Review and New Research Directions

This paper highlights the relationship between migration and female breast cancer. A comprehensive review aimed at identifying risk and protective factors that cut across races and ethnicities was performed. A total of 79 studies (1971-2005) from 16 countries were reviewed. The findings are consistent with existing knowledge about the importance of potentially modifiable environmental and behavioral determinants of risk, acting both pre- and post-migration. While the acculturation-based risk transition model is strong, it is not always supported. As a new direction for migrant studies, we extrapolate the review findings to the experience of Eastern European (EE) immigrants. Health data on this population, typically characterized by low health motivation and passive receipt of preventive efforts, are largely unavailable. Based on relevant theory, empirical and qualitative studies, two breast cancer prevention models for the EE immigrant population are proposed and the need for future research using ethnically disaggregated data is discussed.

Cancer survival in Estonian migrants to Sweden

OBJECTIVE

To quantify the eventual extra loss of life incurred to cancer patients in Estonia compared with those in Sweden that was possibly attributable to differences in society.

DESIGN

Population based survival of cancer patients in Estonia was compared with that of Estonian immigrants to Sweden and that of all cancer patients in Sweden. The cancer sites studied were female breast and ovary, male lung and prostate, and male and female stomach and colon.

SETTING

Data on incident cases of cancer were obtained from the population based Swedish and Estonian cancer registries.

PARTICIPANTS

Data from Estonian patients in Sweden, Estonian patients in Estonia, and patients from the total Swedish population were included in the study.

MAIN RESULTS

Differences in survival among the three populations, controlling for follow-up time and age at diagnosis, were observed in breast, colon, lung, ovarian, and prostate cancers. The survival rates of Estonians living in Sweden and the total population of Sweden were better than that of the Estonians living in Estonia. For cancers of the breast and prostate, the excess mortality in the older age group (75 and above) was much greater in Estonia than in the other populations.

CONCLUSIONS

Most differences in cancer survival between Estonian and Swedish populations studied could be attributed to a longer delay in diagnosis, and also to inferior treatment (including access to treatment) in Estonia compared with Sweden. Estonia's lag in socioeconomic development, particularly in its public health organisation and funding, is probably the main source of the differences observed.

Bladder cancer in Estonia, 1968-1992: incidence, mortality, prevalence and survival

This paper summarizes what is known about the occurrence and survival of bladder cancer in Estonia from 1968 to 1992. In 1988-92 the age standardized (world standard) incidence rate of bladder cancer was 11.1 per 100,000 person-years in males and 2.0 in females, and the age standardized mortality rate was 8.2 and 2.7, respectively; by July 1, 1990 the age standardized prevalence rate was 41.5 and 14.7, respectively. Between 1968-72 and 1988-92, incidence increased by 1.26 times (95% confidence interval 1.09 to 1.46) among males; incidence rates for females did not show a consistent trend. The time trends in mortality generally paralleled the trends in incidence. Higher rates of bladder cancer were found among males in five large towns. For patients diagnosed in 1983-87, the five-year relative survival was 32.4% (95% confidence interval 27.0 to 37.8) for males and 32.5% (23.8 to 41.2) for females; throughout the 20 years there was no improvement in survival. As the survival rates are less favorable than those in the Nordic countries, further hospital-based studies are needed to investigate the relation between survival and clinical characteristics.

Descriptive epidemiology of cancer around the Baltic Sea

Baltic Sea countries--Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, the Russian Federation and Sweden--have expressed deep interest in developing collaborative research projects chiefly in descriptive epidemiology of cancer. In order to assess potentials for joint studies, an attempt was undertaken to characterize cancer registration, cancer incidence patterns, temporal trends in cancer mortality and research productivity between these countries. Standards of cancer registration are highest in the Nordic countries (Denmark, Finland, Sweden). These countries and Germany are also doing more productive research. Great differences in incidence and in mortality trends around the Baltic Sea offer promising opportunities for epidemiologic studies. Scarcity of well-trained professional epidemiologists and other resources in Latvia, Lithuania, Estonia and the Russian Federation is the main factor limiting the planning of joint large-scale epidemiologic studies of cancer.