Cancer risks in first-generation immigrants to Sweden

Gendered interpretations of the causes of breast cancer: a structured review of migrant studies

BACKGROUND

Breast cancer is the most prevalent cancer in women worldwide. Despite it having an etiology that has fixed, genetic as well as modifiable, environmental risk factors, the narrative around breast cancer prevention emphasizes gendered interpretations of the etiology, such as "reproductive factors cause breast cancer" and women should change their behaviors to reduce their risk. Since migrant studies can distinguish environmental from genetic risk factors, we conducted a structured review of migrant studies and assessed prominent cancer website resources to determine evidence of gender bias between breast and prostate cancer.

METHODS

We searched ten online databases for articles with migration as the exposure and breast cancer mortality and/or incidence as the outcome. We also searched using prostate cancer as the outcome to generate a comparison group. We developed rubrics to categorize the studies by study design (single, double, and time dimensional), convergence (a change in incidence or mortality for the migrant population), and concordance (consistency between results and author-attributed etiology). We used chi-square tests to test for differences by cancer type. We web-scraped four notable cancer websites to extract website layouts, risk factor information, and language describing breast cancer etiology and compared it to the content used for prostate cancer.

FINDINGS

Of all 140 studies and 220 comparisons, breast (n = 131) outnumbered prostate cancer studies (n = 89; p-value = 0·005). For both cancers, studies that compared all three populations (the non-migrant, origin, and destination population outcomes) or measured length of stay demonstrated that cancer rates converged with migration. Most authors attributed breast cancer etiology to genetic and environmental factors. Yet, the migrant study results were inconsistent with public health messaging; all four websites framed breast cancer as more modifiable than prostate cancer.

CONCLUSION

Research efforts and public health messaging for breast cancer should consider gendered barriers to changing individual-level risk factors and develop more prevention strategies at the health systems level.

All-cancer incidence and mortality in Pakistanis, Bangladeshis, and their descendants in England and Wales

BACKGROUND

This paper identifies differences in all-cancer incidence and mortality between Pakistani-born (PB), Bangladeshi-born (BB), their descendants, and the White British (WB) in England and Wales. Pakistanis and Bangladeshis are the most marginalised and disadvantaged groups in England and Wales yet, are found to have low cancer mortality and low all-cause mortality. Previous studies though have not looked at generational differences, applied individual-level data nor separated Pakistanis and Bangladeshis from each other and other Asian groups.

METHODS

We use the Office for National Statistics Longitudinal Study of England and Wales which is a 1% representative sample of the population. We apply event history analysis on a study period from 1971 to 2016, following individuals from age 20 until a first cancer incidence, censoring at emigration or death. We observe 10,885,500 person-years and 71,926 cancer incidences for WB; 125,700 person-years and 295 events for PB; 53,900 person-years and 113 events for BB and 26,900 person-years and 24 events for descendants. Following incidence, we study a maximum of ten years until a death from cancer, or censoring. In this second analysis on mortality our sample has 329,700 person-years and 31,689 cancer deaths for WB; 1,200 person-years and 104 events for PB; 400 person-years and 50 events for BB and 100 person-years and 10 events for descendants.

RESULTS

Results from the fully adjusted models show that the risk of cancer incidence is lower for PB, BB and descendants compared to the WB native group. Estimated hazard ratio (HR) equals 0.42 for PB (95% confidence interval (CI): 0.38-0.47), for BB HR is 0.38 (CI: 0.32-0.46) and, for descendants HR is 0.36 (CI: 0.24-0.54). Results for cancer mortality after incidence show HR for PB is 0.93 (CI: 0.76-1.12), for BB it is 0.95 (CI: 0.72-1.25) and for descendants HR equals 1.62 (CI: 0.87-3.02 - significant at 90%).

CONCLUSIONS

Using high quality representative data, we show that lower incidence of cancer and not better survival is the driver of the low cancer mortality previously found. This advantage persists across immigrant generations, but all-cancer mortality following incidence may be elevated for descendants.

Cancer incidence in immigrants by geographical area of origin: data from the Veneto Tumour Registry, Northeastern Italy

Objective

We investigated whether there are differences in cancer incidence by geographical area of origin in North-eastern Italy.

Methods

We selected all incident cases recorded in the Veneto Tumour Registry in the period 2015-2019. Subjects were classified, based on the country of birth, in six geographical areas of origin (Italy, Highly Developed Countries-HDC, Eastern Europe, Asia, Africa, South-central America). Age-standardized incidence rates and incidence rate ratio (IRR) were calculated, for all cancer sites and for colorectal, liver, breast and cervical cancer separately.

Results

We recorded 159,486 all-site cancer cases; 5.2% cases occurred in subjects born outside Italy, the majority from High Migratory Pressure Countries (HMPC) (74.3%). Incidence rates were significantly lower in subjects born in HMPC in both sexes. Immigrants, in particular born in Asia and Africa, showed lower rates of all site cancer incidence. The lowest IRR for colorectal cancer was observed in males from South-Central America (IRR 0.19, 95%CI 0.09-0.44) and in females from Asia (IRR 0.32, 95%CI 0.18-0.70). The IRR of breast cancer appeared significantly lower than Italian natives in all female populations, except for those coming from HDC. Females from Eastern Europe showed a higher IRR for cervical cancer (IRR 2.02, 95%CI 1.57-2.61).

Conclusion

Cancer incidence was found lower in subjects born outside Italy, with differences in incidence patterns depending on geographical area of origin and the cancer type in question. Further studies, focused on the country of birth of the immigrant population, would help to identify specific risk factors influencing cancer incidence.

Age-period-cohort analysis and projection of cancer mortality in Hong Kong, 1998-2030

OBJECTIVES

To explore the relationship between immigration groups and cancer mortality, this study aimed to explore age, period, birth cohort effects and effects across genders and immigration groups on mortality rates of lung, pancreatic, colon, liver, prostate and stomach cancers and their projections.

DESIGN, SETTING, AND PARTICIPANTS

Death registry data in Hong Kong between 1998 and 2021, which were stratified by age, sex and immigration status. Immigration status was classified into three groups: locals born in Hong Kong, long-stay immigrants and short-stay immigrants.

METHODS

Age-period-cohort (APC) analysis was used to examine age, period, and birth cohort effects for genders and immigration groups from 1998 to 2021. Bayesian APC models were applied to predict the mortality rates from 2022 to 2030.

RESULTS

Short-stay immigrants revealed pronounced fluctuations of mortality rates by age and of relative risks by cohort and period effects for six types of cancers than those of long-stay immigrants and locals. Immigrants for each type of cancer and gender will be at a higher mortality risk than locals. After 2021, decreasing trends (p<0.05) or plateau (p>0.05) of forecasting mortality rates of cancers occur for all immigration groups, except for increasing trends for short-stay male immigrants with colon cancer (p<0.05, Avg+0.30 deaths/100 000 per annum from 15.47 to 18.50 deaths/100 000) and long-stay male immigrants with pancreatic cancer (p<0.05, Avg+0.72 deaths/100 000 per annum from 16.30 to 23.49 deaths/100 000).

CONCLUSIONS

Findings underscore the effect of gender and immigration status in Hong Kong on mortality risks of cancers that immigrants for each type of cancer and gender will be at a higher mortality risk than locals.

Migrant mortality by duration of residence and co-ethnic density - A register-based study on Finnish migrants in Sweden with matched controls in the origin and the destination

Migrant health depends on factors both at the origin and at the destination. Health-related behaviors established before migration may change at the destination. We compare the mortality rates from alcohol- and smoking-related causes and cardiovascular diseases (CVD) of Finnish migrants in Sweden to matched controls in both Sweden and Finland with similar sociodemographic characteristics. Migrant mortality rates from behavioral risk factors lie in-between the rates of non-migrants in the origin and destination. A longer duration of residence is associated with lower mortality and with mortality patterns more similar to Swedes for men. For women, a longer duration of residence is associated with higher mortality, in particular smoking-related mortality, with no tendency of a gradual convergence. The density of Finnish migrants in the local area is modestly associated with mortality. However, CVD mortality tends to be higher and more similar to the level in Finland for migrants in areas with a higher density of Finnish migrants. The results suggest that behavioral changes can reduce mortality differences between migrants and natives and that this can be either beneficial or detrimental to migrant health.

Cervical, liver and stomach cancer incidence and mortality in non-Western immigrant women: a retrospective cohort study from four Nordic countries

BACKGROUND

Cervical, liver and stomach cancers are the most common infection-associated malignancies and the leading cause of morbidity in non-Western regions. We compared the incidence and mortality of these cancers between non-Western immigrant and non-immigrant Nordic female populations. We also analysed the effect of age at immigration, duration of residence and education on cancer burden.

MATERIAL AND METHODS

Study population consisted of women residents in Denmark, Finland, Iceland and Norway in 1973-2020. Non-Western women contributed 3.1% of the total 260 million person-years at risk. All women were followed from their 20th birthday, or from the date of immigration if after, until the date of their first primary cancer diagnosis, death, emigration, or the end of the country-specific study period. All data were adjusted for 10-year age groups and calendar periods, and immigrant data was further broken down by region of birth, age at immigration and education level. Country-specific estimates were produced by multivariable Poisson regression and pooled in Finland with a random effects model.

RESULTS

Altogether, there were 60 982 cases of cervical, liver and stomach cancer in the study population, causing 36 582 deaths. The immigrant women had significantly higher liver (rate ratio [RR] 1.78, 95% confidence interval (CI) 1.03-3.06) and stomach cancer incidence (RR 1.68, CI 1.29-2.18), and stomach cancer mortality (RR 1.49, CI 1.17-1.92) than non-immigrant women. In the immigrant population, high education was related to lower incidence and mortality of studied cancers. The rate ratio of cervical cancer decreased with duration of residence and increased with rising age at immigration.

CONCLUSION

Due to the increased incidence and mortality of infection-related cancers and changes in cancer patterns by age at immigration and duration of residence, attention should be paid to targeted health care services for immigrants. Special efforts should be given to women who have spent their youth in high-risk areas.

Long-Term Periodic and Conditional Survival Trends in Prostate, Testicular, and Penile Cancers in the Nordic Countries, Marking Timing of Improvements

Survival studies are important tools for cancer control, but long-term survival data on high-quality cancer registries are lacking for all cancers, including prostate (PC), testicular (TC), and penile cancers. Using generalized additive models and data from the NORDCAN database, we analyzed 1- and 5-year relative survival for these cancers in Denmark (DK), Finland (FI), Norway (NO), and Sweden (SE) over a 50-year period (1971-2020). We additionally estimated conditional 5/1-year survival for patients who survived the 1st year after diagnosis. Survival improved early for TC, and 5-year survival reached 90% between 1985 (SE) and 2000 (FI). Towards the end of the follow-up, the TC patients who had survived the 1st year survived the next 4 years with comparable probability to the background population. For PC, the 90% landmark was reached between 2000 (FI) and after 2010 (DK). For penile cancer, 5-year survival never reached the 90% landmark, and the improvements in survival were modest at best. For TC, early mortality requires attention, whereas late mortality should be tackled for PC. For penile cancer, the relatively high early mortality may suggest delays in diagnosis and would require more public awareness and encouragement of patients to seek medical opinion. In FI, TC and penile cancer patients showed roughly double risk of dying compared to the other Nordic countries, which warrants further study and clinical attention.

Cancer, cardiovascular disease, and all-cause mortality in Iraqi- and Swedish-born individuals in Sweden: the MEDIM cohort study

Immigrants from the Middle East to Sweden have a twice as high prevalence of type 2 diabetes (T2D) and obesity as native-born Swedes. Both obesity and T2D have been linked to increased incidence of cancer, cardiovascular disease (CVD) and all-cause mortality (ACM); however, data on differences between ethnicities are scarce. In a population-based cohort we aimed to study the impact of Middle Eastern and European ethnicity on ACM, cancer- and CVD related mortality, incidence of cancer and CVD in an eight-year follow-up study. Methods: People born in Iraq or Sweden, who were 30-75 years of age, were invited from 2010 to 2012 to participate in the population based MEDIM study including a health exam, fasting blood sampling, assessment of insulin secretion and action (through oral glucose tolerance test) and questionnaires assessing history of CVD, cancer and T2D. Register data were retrieved from baseline until the 31st of December 2018 from the Swedish National Patient Register and Cause of Death register regarding CVD diagnosis, cancer diagnosis and cause of death. Information regarding diabetes diagnosis was retrieved from the National Diabetes Register. Individuals with a history of cancer or CVD at baseline were excluded. Cox regression analysis was assessed to study the adjusted hazard ratios (HR) for the relationships between ethnicity and ACM, cancer events, CVD events, death from cancer, and death from CVD, with adjustments for age, sex, anthropometrical measures, T2D and lifestyle. A total of 1398 Iraqi- and 757 Swedish-born residents participated in the study. ACM was considerably lower in Iraqi- compared to Swedish-born individuals HR 0.32 (95% CI 0.13-0.79) (p < 0.05). Furthermore, cancer related morbidity and mortality HR 0.39 (0.22-0.69) (p < 0.01) as well as CVD related morbidity and mortality HR 0.56 (0.33-0.95) (p < 0.05) were lower in the Iraqi-born group compared to the Swedish-born group for. The differences in mortality and cancer rates across ethnicities are not fully explained by anthropometric, environmental or metabolic measures but lie elsewhere. Further studies are needed to increase the understanding of contributing mechanisms.

Mortality Advantage Reversed: The Causes of Death Driving All-Cause Mortality Differentials Between Immigrants, the Descendants of Immigrants and Ancestral Natives in Sweden, 1997-2016

A small but growing body of studies have documented the alarming mortality situation of adult descendants of migrants in a number of European countries. Nearly all of them have focused on all-cause mortality to reveal these important health inequalities. This paper takes advantage of the Swedish population registers to study all-cause and cause-specific mortality among men and women aged 15-44 in Sweden from 1997 to 2016 to a level of granularity unparalleled elsewhere. It adopts a multi-generation, multi-origin and multi-cause-of-death approach. Using extended, competing-risks survival models, it aims to show (1) how the all-cause mortality of immigrants arriving as adults (the G1), immigrants arriving as children (the G1.5) and children of immigrants born in Sweden to at least one immigrant parent (the G2) differs versus ancestral Swedes and (2) what causes-of-deaths drive these differentials. For all-cause mortality, most G1 (not Finns or Sub-Saharan Africans) have a mortality advantage. This contrasts with a near systematic reversal in the mortality of the G1.5 and G2 (notably among men), which is driven by excess accident and injury, suicide, substance use and other external cause mortality. Given that external causes-of-death are preventable and avoidable, the findings raise questions about integration processes, the levels of inequality immigrant populations are exposed to in Sweden and ultimately, whether the legacy of immigration has been positive. Strengths of the study include the use of quality data and advanced methods, the granularity of the estimates, and the provision of evidence that highlights the precarious mortality situation of the seldom-studied G1.5.

Health inequalities among Russian-born immigrant women in Finland: longitudinal analysis on cervical cancer incidence and participation to screening

Research has documented both lower and higher cancer incidence among migrants. Evidence among the large Russian-born migrant population, however, is scarce. We examined cervical cancer incidence and screening participation among Russian-born immigrant women in Finland, a country with complete cancer registration and universal public health care including organized cancer screening. Our study population included all the women that resided in Finland during 1970–2017 and was formed linking individual-level data from four nationwide registries. The linked data sets on cancer and cancer screening were analysed separately using different statistical models. Russian-born immigrant women had increased (+62%) incidence of cervical cancer compared to the general Finnish female population, and they participated in cervical cancer screening slightly less than other women. Our findings showed no consistent transition pattern in cancer incidence or screening participation rate with duration of stay. Potential explanations for the observed differences include institutional and behavioural factors. Cervical cancer is one of the most preventable cancers, and cancer screening can both prevent and reduce incidence and mortality of cervical cancer. Efforts should be made to encourage migrant populations to participate in cervical screening.

No evidence to support the impact of migration background on treatment response rates and cancer survival: a retrospective matched-pair analysis in Germany

Background

Immigration has taken the central stage in world politics, especially in the developed countries like Germany, where the continuous flow of immigrants has been well documented since 1960s. Strikingly, emerging data suggest that migrant patients have a poorer response to the treatment and lower survival rates in their new host country, raising concerns about health disparities. Herein, we present our investigation on the treatment response rate and cancer survival in German patients with and without an immigrant background that were treated at our comprehensive cancer center in Germany.

Methods

Initially, we considered 8162 cancer patients treated at the Center for Integrated Oncology (CIO), University Hospital Bonn, Germany (April 2002–December 2015) for matched-pair analysis. Subsequently, the German patients with a migration background and those from the native German population were manually identified and catalogued using a highly specific name-based algorithm. The clinical parameters such as demographic characteristics, tumor characteristics, defined staging criteria, and primary therapy were further adjusted. Using these stringent criteria, a total of 422 patients (n = 211, Germans with migration background; n = 211, native German population) were screened to compare for the treatment response and survival rates (i.e., 5-year overall survival, progression-free survival, and time to progression).

Results

Compared to the cohort with migration background, the cohort without migration background was slightly older (54.9 vs. 57.9 years) while having the same sex distribution (54.5% vs. 55.0% female) and longer follow-up time (36.9 vs. 42.6 months). We did not find significant differences in cancer survival (5-year overall survival, P = 0.771) and the response rates (Overall Remission Rate; McNemar’s test, P = 0.346) between both collectives.

Conclusion

Contrary to prior reports, we found no significant differences in cancer survival between German patients with immigrant background and native German patients. Nevertheless, the advanced treatment protocols implemented at our comprehensive cancer center may possibly account for the low variance in outcome. To conduct similar studies with a broader perspective, we propose that certain risk factors (country-of-origin-specific infections, dietary habits, epigenetics for chronic diseases etc.) should be considered, specially in the future studies that will recruit new arrivals from the 2015 German refugee crisis.

Is low-level metal exposure related to testicular cancer?

Disruption of element homeostasis may contribute to increased susceptibility of men to cancer development. Whether environmental low-level metal exposure could contribute to the pathogenesis of testicular cancer is unknown. Comparison of the level of 18 elements in whole blood, serum and urine and parameters of oxidative stress/antioxidant status between men with testicular germ cell tumors (TGCT) and healthy men showed significant difference between the groups in most parameters. The results of linear discriminant analysis with a discrimination rate of 96% indicated whole blood Ca, Co, Cu, Fe, K, Mg, Na and Zn, serum Ca, Cu, Na and Ni, and urine Cd, Co, Fe and Mn being the strongest predictors of illness. TGCT patients had a significant increase in serum and blood Cu and decrease in serum Fe and blood Zn with cancer progression. Significantly higher concentrations of Al, As, Pb, and Ni in whole blood/serum of men with TGCT confirm the hypothesis that low-level environmental exposure to these elements may contribute to cancer development. Relationship between elements concentrations and treatment outcomes should be carefully monitored during cancer treatment since high concentrations of commonly used platinum-based chemotherapeutics may additionally disturb the homeostasis of elements.

Social determinants of colorectal cancer risk, stage, and survival: a systematic review

BACKGROUND

Several social determinants of health have been examined in relation to colorectal cancer incidence, stage at diagnosis, and survival including income, education, neighborhood disadvantage, immigration status, social support, and social network. Colorectal cancer incidence rates are positively associated with income and other measures of socioeconomic status. In contrast, low socioeconomic status tends to be associated with poorer survival.

METHODS

The present review is based upon bibliographic searches in PubMed and CINAHL and relevant search terms. Articles published in English from 1970 through April 1, 2019 were identified using the following MeSH search terms and Boolean algebra commands: colorectal cancer AND (incidence OR stage OR mortality) AND (social determinants OR neighborhood disadvantage OR racial discrimination OR immigration OR social support).

RESULTS

This review indicates that poverty, lack of education, immigration status, lack of social support, and social isolation play important roles in colorectal cancer stage at diagnosis and survival.

CONCLUSIONS

To address social determinants of colorectal cancer, effective interventions are needed that account for the social contexts in which patients live.

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.

BRCA2 gene mutation and prostate cancer risk. Comprehensive review and update

The second most common type of tumor worldwide is prostate cancer (PCa). Certain genetic factors contribute to a risk of developing PCa of as much as 40%. BRCA1 and BRCA2 mutations have linked with an increased risk for breast, ovarian, and PCa. However, BRCA2 is the most common gene found altered in early-onset of PCa in males younger than 65. BRCA2 mutation has a higher chance of developing an advanced stage of the disease, resulting in short survival time. This review aimed to describe the genetic changes in BRCA2 that contribute to the risk of PCa, to define its role in the early diagnosis in a man with a strong family history, and to outline the purpose of genetic testing and counseling. Also, the review summarizes the impact of BRCA2 gene mutation in localized PCa, and the treatment strategies have used for PCa patients with a BRCA2 modification.

Prostate cancer in the Arab population. An overview

This review evaluated prostate cancer studies from around the world and investigated the causes of differences among them. Prostate cancer incidence and mortality rates showed significant discrepancies between countries and ethnicities. In North America as well as in other western countries, the most common cancer was found to be prostate cancer; however, it appears to be not as prevalent among men in the Middle East and North Africa. Statistics show that screening of prostate-specific antigen levels should be applied depending on ethnicity and age. Other environmental aspects such as dietary and androgenic factors are believed to have caused these differences.

Cancer risk in different generations of Middle Eastern immigrants to California, 1988-2013

The objective of this study is to compare cancer risk among different generations of Middle Eastern immigrants (ME) and non-Hispanic whites (NHW) in California between 1988 and 2013. We used data from the California Cancer Registry to identify invasive primary incident cancer cases in three population groups: (i) first-generation ME immigrants, (ii) second- or subsequent-generations ME immigrants, and (iii) NHW. Proportional incidence ratio (PIR) was used to compare cancer risk of the 15 selected most common cancers in the 3 population groups taking into consideration time since immigration for first-generation ME immigrants. First generation ME immigrants were more likely to be at increased risk of stomach (PIR= 3.13) and hepatobiliary (PIR = 2.27) cancers in females and thyroid (PIR = 2.19) and stomach (PIR = 2.13) cancers in males in comparison with NHW. Second- or subsequent-generations ME immigrants were at increased risk of thyroid cancer (PIR = 1.43 in females and 2.00 in males) in comparison with NHW, and malignant melanoma cancer (PIR = 4.53 in females and 4.61 in males) in comparison with first-generation ME immigrants. The risk levels of breast, thyroid and bladder cancers in ME first generation were significantly higher compared to NHW regardless of time spent in the United States suggesting the role of genetic predisposition, and/or cultural characteristics associated with these cancers. The results suggest that differences in cancer risk between ME first-generation immigrants and NHW change in second or subsequent generations, approaching the risk level of NHW and indicating the impact of acculturation in this immigrant population.

Mortality by country of birth in the Nordic countries - a systematic review of the literature

Background

Immigration to the Nordic countries has increased in the last decades and foreign-born inhabitants now constitute a considerable part of the region’s population. Several studies suggest poorer self-reported health among foreign-born compared to natives, while results on mortality and life expectancy are inconclusive. To date, few studies have summarized knowledge on mortality differentials by country of birth. This article aims to systematically review previous results on all-cause and cause-specific mortality by country of birth in the Nordic countries.

Methods

The methodology was conducted and documented systematically and transparently using a narrative approach. We identified 43 relevant studies out of 6059 potentially relevant studies in August 2016, 35 of which used Swedish data, 8 Danish and 1 Norwegian.

Results

Our findings from fully-adjusted models on Swedish data support claims of excess mortality risks in specific categories of foreign-born. Most notably, immigrants from other Nordic countries, especially Finland, experience increased risk of mortality from all causes, and specifically by suicide, breast and gynaecological cancers, and circulatory diseases. Increased risks in people from Central and Eastern Europe can also be found. On the contrary, decreased risks for people with Southern European and Middle Eastern origins are found for all-cause, suicide, and breast and gynaecological cancer mortality. The few Danish studies are more difficult to compare, with conflicting results arising in the analysis. Finally, results from the one Norwegian study suggest significantly decreased mortality risks among foreign-born, to be explored in further research.

Conclusions

With new studies being published on mortality differentials between native and foreign-born populations in the Nordic countries, specific risk patterns have begun to arise. Regardless, data from most Nordic countries remains limited, as does the information on specific causes of death. The literature should be expanded in upcoming years to capture associations between country of birth and mortality more clearly.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4447-9) contains supplementary material, which is available to authorized users.

Cancer and the healthy immigrant effect: a statistical analysis of cancer diagnosis using a linked Census-cancer registry administrative database

BACKGROUND

A large volume of research has been published on both the socio economic and demographic determinants of cancer and on the health of immigrants and minority groups. Yet because of data limitations, little research examines differences in the occurrence of cancer incidence between immigrants and non-immigrants and among immigrants defined by region of birth and time in the host country. In particular it is not known whether a healthy immigrant effect is present for cancer and if so, whether this advantage is lost with additional years of residence in the host country.

METHODS

This paper uses a large data file from Statistics Canada that links Census information on immigrant status, socioeconomic status including educational attainment, and other person-level information with administrative data on cancer and mortality over a continuous 13 year period of observation. It estimates discrete and continuous time duration models to identify differences in cancer diagnosis by immigrant subgroup after controlling for a variety of potential confounders. Differences in historical smoking behavior are not observable at the individual level in the dataset but are accounted for indirectly using various methods.

RESULTS

Results in general confirm the existence of a healthy immigrant effect for cancer in that, overall, recent immigrants to Canada are significantly less likely than otherwise comparable non-immigrant Canadians to be diagnosed with any cancer and the most common forms of cancer by site. As well, this gap appears to decline with additional years in Canada for immigrant men and women, eventually converging to Canadian-born levels. Differentiating among immigrant subgroups by period of arrival and country of birth reveals significant variation across immigrant subgroups, with immigrant men and women from developing countries typically having a lower likelihood of being diagnosed with cancer than immigrants from the US, UK and continental Europe. As well, controlling for immigrant heterogeneity this way weakens the conclusion that the gap narrows with years in Canada. Immigrant men overall continue to exhibit convergence to Canadian-born levels for diagnosis of any cancer and for prostate cancer, while immigrant women exhibit narrowing over time only for breast cancer. Although smoking behavior is not directly observed, controlling for subgroup-specific lifetime smoking behavior using survey data has only a relatively minor effect on the estimated differences.

CONCLUSIONS

The specificity of the results by cancer type, gender, immigrant status and ethnicity provides useful guidance for future research by helping to narrow the possible channels through which social and economic characteristics may be affecting cancer incidence.

Lung cancer among native and foreign-born Swedes: histopathology, treatment, and survival

BACKGROUND

Lung cancer (LC) is the leading cause of cancer-related death worldwide, including Sweden. Several studies have shown that socioeconomic status affects the risk, treatment, and survival of LC. Due to immigration after Second World War, foreign-born people constitute 12.5% of the Swedish population. We wanted to investigate if there were any differences in LC management, treatment and survival among the foreign-born Swedes (FBS) compared to the native Swedish population (NatS) in Stockholm.

MATERIAL AND METHODS

A retrospective analysis of all patients diagnosed with non-small cell lung cancer (NSCLC) at the Department of Respiratory Medicine and Allergy, Karolinska University Hospital, Solna from 1 January 2003 to 31 December 2008 was made. In all, 2041 cases of LC were diagnosed, thereof 1803 with NSCLC. Of these, 211 (11.7%) were FBS.

RESULTS

The mean age of NatS and FBS patients was 69.9 years, median 70 (range 26-96) and 66.0 years, median 66 (range 38-94), respectively (p < 0.001). In all, 89.8% of NatS and 90.0% of FBS were either smokers or former smokers. Adenocarcinoma was the most common subtype in both groups (NatS 54.7%, FBS 48.3%). In 140 (8.8%) of the NatS and 17 (8.1%) of the FBS the diagnosis was clinical only. There were no significant differences in stage at diagnosis, nor in performance status (PS) or different therapies between the groups. The median overall survival time for the NatS was 272 days and for FBS 328 days, again no significant difference. However, the median overall survival time for female NatS was 318 days and for female FBS 681 days (p = 0.002).

CONCLUSION

FBS patients were significantly younger than NatS at diagnosis, and female FBS lived longer than female NatS, but otherwise there were no significant differences between NatS and FBS patients with LC regarding diagnosis, treatment, and survival.

Pathological outcomes and agressiveness of low-risk prostate cancer in Northern African men

BACKGROUND

Northern African (NAf) men show a high incidence of advanced prostate cancer (PCa) at diagnosis. Several studies suggested the existence of ethnic differences in the PCa aggressiveness and this has led to some concerns related to the inclusion of some ethnic groups into active surveillance protocols.

OBJECTIVE

To evaluate pathological outcomes and aggressiveness of low risk PCa treated by radical prostatectomy in a NAf ethnic group.

SUBJECTS AND METHODS

Data of 147 NAfs, who underwent radical prostatectomy for low risk PCa diagnosed via a 12-core biopsy in 2 academic centers between 2011 and 2015, were reviewed retrospectively to assess rates of worse pathological outcomes defined as: Gleason score upgrade to at least 3+4, upstage to pT3a or higher or pN1, and positive surgical margins.

RESULTS

Overall significant upstage and/or upgrade occurred in 20.2% and positive surgical margins occured in18.3%. In multivariate logistic regression analysis, independent variables that predicted for upstage and/or upgrade or positive surgical margins in the entire cohort were: NCCN risk group (low risk>very low risk), advanced age>60 years, PSA>6ng/ml, PSA density≥0.15, more than 2 positive cores in biopsy, more than 50% cancer involvement in positive cores, clinical stage (T2a>T1c) and UCSF-CAPRA-S score>3.

CONCLUSIONS

Our study found that, at least pathologically, NAf men do not have more aggressive disease than Caucasians and African Americans in both low and very low risk PCa. Thus, we think that active surveillance is a suitable approach for selected patients since there is no definitive data that show a more aggressive natural history of PCa in NAf men.

Prognostic factors and disease-specific survival among immigrants diagnosed with cutaneous malignant melanoma in Sweden

Little is known about cutaneous malignant melanoma (CMM) among immigrants in Europe. We aimed to investigate clinical characteristics and disease-specific survival among first- and second-generation immigrants in Sweden. This nationwide population-based study included 27,235 patients from the Swedish Melanoma Register diagnosed with primary invasive CMM, 1990-2007. Data were linked to nationwide, population-based registers followed up through 2013. Logistic regression and Cox regression models were used to determine the association between immigrant status, stage and CMM prognosis, respectively. After adjustments for confounders, first generation immigrants from Southern Europe were associated with significantly more advanced stages of disease compared to Swedish-born patients [Stage II vs. I: Odds ratio (OR) = 2.37, 95% CI = 1.61-3.50. Stage III-IV vs I: OR = 2.40, 95% CI = 1.08-5.37]. The ORs of stage II-IV versus stage I disease were increased among men (OR = 1.9; 95% CI = 1.1-3.3; p = 0.020), and women (OR = 4.8; 95% CI = 2.6-9.1; p < 0.001) in a subgroup of immigrants from former Yugoslavia compared to Swedish-born patients. The CMM-specific survival was significantly decreased among women from former Yugoslavia versus Swedish-born women [hazard ratio (HR)=2.2; 95% CI = 1.1-4.2; p = 0.043]. After additional adjustments including stage, the survival difference was no longer significant. No survival difference between the second generation immigrant group and Swedish-born patients were observed. In conclusion, a worse CMM-specific survival in women from former Yugoslavia was associated with more advanced stages of CMM at diagnosis. Secondary prevention efforts focusing on specific groups may be needed to further improve the CMM prognosis.

EDC-2: The Endocrine Society's Second Scientific Statement on Endocrine-Disrupting Chemicals

The Endocrine Society's first Scientific Statement in 2009 provided a wake-up call to the scientific community about how environmental endocrine-disrupting chemicals (EDCs) affect health and disease. Five years later, a substantially larger body of literature has solidified our understanding of plausible mechanisms underlying EDC actions and how exposures in animals and humans-especially during development-may lay the foundations for disease later in life. At this point in history, we have much stronger knowledge about how EDCs alter gene-environment interactions via physiological, cellular, molecular, and epigenetic changes, thereby producing effects in exposed individuals as well as their descendants. Causal links between exposure and manifestation of disease are substantiated by experimental animal models and are consistent with correlative epidemiological data in humans. There are several caveats because differences in how experimental animal work is conducted can lead to difficulties in drawing broad conclusions, and we must continue to be cautious about inferring causality in humans. In this second Scientific Statement, we reviewed the literature on a subset of topics for which the translational evidence is strongest: 1) obesity and diabetes; 2) female reproduction; 3) male reproduction; 4) hormone-sensitive cancers in females; 5) prostate; 6) thyroid; and 7) neurodevelopment and neuroendocrine systems. Our inclusion criteria for studies were those conducted predominantly in the past 5 years deemed to be of high quality based on appropriate negative and positive control groups or populations, adequate sample size and experimental design, and mammalian animal studies with exposure levels in a range that was relevant to humans. We also focused on studies using the developmental origins of health and disease model. No report was excluded based on a positive or negative effect of the EDC exposure. The bulk of the results across the board strengthen the evidence for endocrine health-related actions of EDCs. Based on this much more complete understanding of the endocrine principles by which EDCs act, including nonmonotonic dose-responses, low-dose effects, and developmental vulnerability, these findings can be much better translated to human health. Armed with this information, researchers, physicians, and other healthcare providers can guide regulators and policymakers as they make responsible decisions.

Mortality among immigrants in England and Wales by major causes of death, 1971-2012: A longitudinal analysis of register-based data

Recent research has found a migrant mortality advantage among immigrants relative to the UK-born population living in England and Wales. However, while all-cause mortality is useful to show differences in mortality between immigrants and the host population, it can mask variation in mortality patterns from specific causes of death. This study analyses differences in the causes of death among immigrants living in England and Wales. We extend previous research by applying competing-risks survival analysis to study a large-scale longitudinal dataset from 1971 to 2012 to directly compare causes of death. We confirm low all-cause mortality among nearly all immigrants, except immigrants from Scotland, Northern Ireland and the Republic of Ireland (who have high mortality). In most cases, low all-cause mortality among immigrants is driven by lower mortality from chronic diseases (in nearly all cases by lower cancer mortality and in some cases by lower mortality from cardiovascular diseases (CVD)). This low all-cause mortality often coexists with low respiratory disease mortality and among non-western immigrants, coexists with high mortality from infectious diseases; however, these two causes of death contribute little to mortality among immigrants. For men, CVD is the leading cause of death (particularly among South Asians). For women, cancer is the leading cause of death (except among South Asians, for whom CVD is also the leading cause). Differences in CVD mortality over time remain constant between immigrants relative to UK-born, but immigrant cancer patterns shows signs of some convergence to the cancer mortality among the UK-born (though cancer mortality is still low among immigrants by age 80). The study provides the most up-to-date, reliable UK-based analysis of immigrant mortality.

Family history of cancer and the risk of squamous cell carcinoma of oesophagus: a case-control study in Kashmir, India

Background:

Only a few studies have examined the association between family history of cancer (FHC) and the risk of oesophageal squamous cell carcinoma (ESCC) in high incidence areas of ESCC. We conducted a case–control study to evaluate the relationship between FHC and ESCC risk in Kashmir, India, with analysis of detailed epidemiological data and information on multiple gene polymorphisms.

Methods:

We collected detailed information on FHC and a number of socio-demographic and lifestyle factors, and also obtained blood samples for genetic analysis from 703 histopathologically confirmed ESCC cases and 1664 individually matched controls. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results:

Participants who had FHC showed a strong association with ESCC risk, and the risk was stronger when first-degree relatives (FDRs) had FHC (OR=6.8; 95% CI=4.6–9.9). Having a sibling with a cancer showed the strongest association (OR=10.8; 95% CI=6.0–19.3), but having a child with a cancer was not associated with ESCC risk. A history of any cancer in the spouse was also associated with ESCC risk (OR=4.1; 95% CI=1.6–10.2). Those with two or more relatives with FHC were at a higher risk of ESCC. After restricting FHC to familial ESCC only, the above associations were strengthened, except when spouses were affected with ESCC (OR=2.5; 95% CI=0.7–8.9). When we examined the associations between several single-nucleotide polymorphisms and ESCC in those with and without FHC, the associations of variant genotypes in cytochrome P450 (CYP) 2C19 and CYP2D6 and the wild genotype of CYP2E1 with ESCC were much stronger in those with FHC. The FHC had an additive interaction with several risk factors of ESCC in this population.

Conclusion:

Our results showed that FHC was strongly associated with ESCC risk in Kashmir. It seems both genetic factors and shared environment are involved in this association.

Prostate Cancer in the Arab World: A View From the Inside

The rates of prostate cancer vary by more than 50-fold across different international populations. The aim of this review was to explore the differences in epidemiology and risk factors between the Middle Eastern Arab countries and some of the developed countries in Europe and North America. The age-standardized incidence rate of prostate cancer in the Arab countries is still lower than that in the Western countries, but is steadily increasing with time. Several factors come into play to explain this difference. There are health care systems-related factors such as the lack of good population-based registries, and population-related factors. The latter include the relatively young age structure in the Arab countries, lower reported androgen and prostate-specific antigen levels in Arab men, the effect of genetic differences on prostate cancer risk, the metabolic syndrome paradox, and the protective effect of the Mediterranean diet on a subset of the Arab population. In conclusion, the study of prostate cancer in the Arab world represents a challenge with the currently available cancer care systems and the increase in the burden of the disease. A multinational prospective study to investigate the epidemiology of prostate cancer in the Middle East, with specific attention to country/geographic variability along with a comparative analysis to that of the Western hemisphere is needed.

Cancer in immigrants as a pointer to the causes of cancer

The early cancer studies on immigrants, which started to appear some 50 years ago, showed that the incidence in cancers changes to the level of the new host country in one or two generations. These findings were fundamental to the understanding of the environmental etiology of human cancer. Many immigrant groups originate from countries with no cancer registration, and, hence, the immigrant studies may provide estimates on the indigenous cancer rates. The Swedish Family-Cancer Database has been an important source of data for immigrant studies on various diseases. The Database covers the Swedish population of the past 100 years, and it records the country of birth for each subject. A total of 1.79 million individuals were foreign born, Finns and other Scandinavians being the largest immigrant groups. Over the course of years, some 30 publications have appeared relating to cancer in immigrants. In the present article, we will review more recent immigrant studies, mainly among Swedish immigrants, on all cancers and emphasize the differences between ethnic groups. In the second part, we discuss the problem of reliable registration of cancer and compare cancer incidence among non-European immigrants with cancer incidence in countries of origin, as these have now active cancer registries. We discuss the experiences in cancer registration in Morocco and Egypt. We show the usefulness and limitations in predicting cancer incidence in the countries of origin.

Hispano-Americans in Europe: what do we know about their health status and determinants? A scoping review

BACKGROUND

Policy makers and health practitioners are in need of guidance to respond to the growing geographic mobility of Hispano-American migrants in Europe. Drawing from contributions from epidemiology, social sciences, demography, psychology, psychiatry and economy, this scoping review provides an up-to-date and comprehensive synthesis of studies addressing the health status and determinants of this population. We describe major research gaps and suggest specific avenues of further inquiry.

METHODS

We identified systematically papers that addressed the concepts "health" and "Hispano Americans" indexed in five data bases from Jan 1990 to May 2014 with no language restrictions. We screened the 4,464 citations retrieved against exclusion criteria and classified 193 selected references in 12 thematic folders with the aid of the reference management software ENDNOTE X6. After reviewing the full text of all papers we extracted relevant data systematically into a table template to facilitate the synthesising process.

RESULTS

Most studies focused on a particular disease, leaving unexplored the interlinkages between different health conditions and how these relate to legislative, health services, environmental, occupational, and other health determinants. We elucidated some consistent results but there were many heterogeneous findings and several popular beliefs were not fully supported by empirical evidence. Few studies adopted a trans-national perspective and many consisted of cross-sectional descriptions that considered "Hispano-Americans" as a homogeneous category, limiting our analysis. Our results are also constrained by the availability and varying quality of studies reviewed.

CONCLUSIONS

Burgeoning research has produced some consistent findings but there are huge gaps in knowledge. To prevent unhelpful generalisations we need a more holistic and nuanced understanding of how mobility, ethnicity, income, gender, legislative status, employment status, working conditions, neighbourhood characteristics and social status intersect with demographic variables and policy contexts to influence the health of the diverse Hispano-American populations present in Europe.

Male reproductive disorders, diseases, and costs of exposure to endocrine-disrupting chemicals in the European Union

INTRODUCTION

Increasing evidence suggests that endocrine-disrupting chemicals (EDCs) contribute to male reproductive diseases and disorders.

PURPOSE

To estimate the incidence/prevalence of selected male reproductive disorders/diseases and associated economic costs that can be reasonably attributed to specific EDC exposures in the European Union (EU).

METHODS

An expert panel evaluated evidence for probability of causation using the Intergovernmental Panel on Climate Change weight-of-evidence characterization. Exposure-response relationships and reference levels were evaluated, and biomarker data were organized from carefully identified studies from the peer-reviewed literature to represent European exposure and approximate burden of disease as it occurred in 2010. The cost-of-illness estimation utilized multiple peer-reviewed sources.

RESULTS

The expert panel identified low epidemiological and strong toxicological evidence for male infertility attributable to phthalate exposure, with a 40-69% probability of causing 618,000 additional assisted reproductive technology procedures, costing €4.71 billion annually. Low epidemiological and strong toxicological evidence was also identified for cryptorchidism due to prenatal polybrominated diphenyl ether exposure, resulting in a 40-69% probability that 4615 cases result, at a cost of €130 million (sensitivity analysis, €117-130 million). A much more modest (0-19%) probability of causation in testicular cancer by polybrominated diphenyl ethers was identified due to very low epidemiological and weak toxicological evidence, with 6830 potential cases annually and costs of €848 million annually (sensitivity analysis, €313-848 million). The panel assigned 40-69% probability of lower T concentrations in 55- to 64-year-old men due to phthalate exposure, with 24 800 associated deaths annually and lost economic productivity of €7.96 billion.

CONCLUSIONS

EDCs may contribute substantially to male reproductive disorders and diseases, with nearly €15 billion annual associated costs in the EU. These estimates represent only a few EDCs for which there were sufficient epidemiological studies and those with the highest probability of causation. These public health costs should be considered as the EU contemplates regulatory action on EDCs.

The impact of breast cancer knowledge and attitudes on screening and early detection among an immigrant Iranian population in southern California

Few studies explored factors influencing breast cancer screening and early detection behaviors among immigrant Iranian women residing in the USA. Using a cross-sectional survey, a convenience sample of 319 Iranian American women was selected to investigate the impact of breast cancer knowledge and attitude on screening. A self-administered questionnaire assessed breast cancer screening knowledge, attitude, and mammography use (ever, previous year, and future intention). 79 % of the women in the study reported ever receiving at least one mammogram and 74 % received a mammogram in the past year. Personal attitude had an independent significant effect on: mammography use in the last year, ever use of mammography, and future intention to screen. Knowledge and morality-induced attitude influenced screening behavior but not significantly. Interventions targeting breast cancer screening among immigrant Iranian women in the USA should focus on enhancing personal attitudes in order to influence actual screening behavior.

Causes of death among undocumented migrants in Sweden, 1997-2010

BACKGROUND

Undocumented migrants are one of the most vulnerable groups in Swedish society, where they generally suffer from poor health and limited health care access. Due to their irregular status, such migrants are an under-researched group and are not included in the country's Cause of Death Register (CDR).

OBJECTIVE

To determine the causes of death among undocumented migrants in Sweden and to ascertain whether there are patterns in causes of death that differ between residents and undocumented migrants.

DESIGN

This is a cross-sectional study of death certificates issued from 1997 to 2010 but never included in the CDR from which we established our study sample of undocumented migrants. As age adjustments could not be performed due to lack of data, comparisons between residents and undocumented migrants were made at specific age intervals, based on the study sample's mean age at death±a half standard deviation.

RESULTS

Out of 7,925 individuals surveyed, 860 were classified as likely to have been undocumented migrants. External causes (49.8%) were the most frequent cause of death, followed by circulatory system diseases, and then neoplasms. Undocumented migrants had a statistically significant increased risk of dying from external causes (odds ratio [OR] 3.57, 95% confidence interval [CI]: 2.83-4.52) and circulatory system diseases (OR 2.20, 95% CI: 1.73-2.82) compared to residents, and a lower risk of dying from neoplasms (OR 0.07, 95% CI: 0.04-0.14).

CONCLUSIONS

We believe our study is the first to determine national figures on causes of death of undocumented migrants. We found inequity in health as substantial differences in causes of death between undocumented migrants and residents were seen. Legal ambiguities regarding health care provision must be addressed if equity in health is to be achieved in a country otherwise known for its universal health coverage.

Mortality differentials by immigrant groups in Sweden: the contribution of socioeconomic position

OBJECTIVES

We studied mortality differentials between specific groups of foreign-born immigrants in Sweden and whether socioeconomic position (SEP) could account for such differences.

METHODS

We conducted a follow-up study of 1 997 666 men and 1 964 965 women ages 30 to 65 years based on data from national Swedish total population registers. We examined mortality risks in the 12 largest immigrant groups in Sweden between 1998 and 2006 using Cox regression. We also investigated deaths from all causes, circulatory disease, neoplasms, and external causes.

RESULTS

We found higher all-cause mortality among many immigrant categories, although some groups had lower mortality. When studying cause-specific mortality, we found the largest differentials in deaths from circulatory disease, whereas disparities in mortality from neoplasms were smaller. SEP, especially income and occupational class, accounted for most of the mortality differentials by country of birth.

CONCLUSIONS

Our findings stressed that different aspects of SEP were not interchangeable in relation to immigrant health. Although policies aimed at improving immigrants' socioeconomic conditions might be beneficial for health and longevity, our findings indicated that such policies might have varying effects depending on the specific country of origin and cause of death.

Differences in the cancer burden among foreign-born and US-born Arab Americans living in metropolitan Detroit

PURPOSE

Migrant studies often provide clues for cancer etiology. We estimated the cancer burden among Arab Americans (ArA) by immigrant status in the metropolitan Detroit area, home to one of the highest concentrations of ArA in USA.

METHODS

A validated name algorithm was used to identify ArA cancer cases diagnosed 1990-2009 in the Detroit SEER database. Recorded birthplace was supplemented with imputation of nativity using birthdate and social security number. Age-adjusted, gender-specific proportional incidence ratios and 95 % confidence intervals were calculated comparing all ArA, foreign-born ArA, and US-born ArA, to non-Hispanic Whites (NHW).

RESULTS

Foreign-born ArA males had higher proportions of multiple myeloma, leukemia, kidney, liver, stomach, and bladder cancer than NHW, while bladder cancer and leukemia were higher among US-born ArA males. For ArA women, gall bladder and thyroid cancers were proportionally higher among both foreign- and US-born compared with NHW. Stomach cancer was proportionally higher only among foreign-born women.

CONCLUSIONS

Cancer proportional incidence patterns among ArA show some similarity to other migrant groups, with higher proportional incidences of stomach and liver cancers among foreign-born than US-born. Other patterns, such as tobacco-related cancers among ArA men and gall bladder and thyroid cancers among ArA women, will require more investigation of genetic, epigenetic, and environmental factors.

Ethnicity is a strong predictor for Helicobacter pylori infection in young women in a multi-ethnic European city

BACKGROUND AND AIM

At the same time that Helicobacter pylori prevalence is declining in Western countries, immigrants from developing countries with high H. pylori prevalence have settled in Western urban areas. Actual epidemiological data on H. pylori in a migrant community may help in realizing a more selective approach to assess H. pylori-related diseases. We aimed to define H. pylori prevalence as well as risk groups for H. pylori in a cohort of young women living in a multi-ethnic European city.

METHODS

We measured Immunoglobulin G (IgG) anti-H. pylori and CagA-antibodies in serum of pregnant women included in a population-based prospective cohort study, the Generation R study. Information on demographics and socioeconomic status was collected by questionnaires. Chi-square and logistic regression were used.

RESULTS

In total, 3146 (46%) of the 6837 tested women (mean age 29.7 ± 5.3) were H. pylori-positive and 1110 (35%) of them were CagA-positive. The H. pylori prevalence in Dutch women was 24%, which was significantly lower than in non-Dutch women (64%; P < 0.001). In particular, H. pylori positivity was found in 92% of Moroccan (odds ratio 19.2; 95% confidence interval 11.8-32.0), 80% of Cape Verdean (7.6; 5.0-11.5), 81% of Turkish (9.0; 6.7-12.1), 60% of Dutch Antillean (3.3; 2.3-4.7), and 58% of Surinamese women (3.0; 2.3-3.8). Among H. pylori-positive Dutch subjects, 19% were CagA-positive compared with 40% of the non-Dutch subjects (P < 0.001).

CONCLUSIONS

Despite a general trend of declining prevalence in Western countries, H. pylori remains highly prevalent in migrant communities, which may constitute target groups for screening and eradication to prevent H. pylori-related diseases.

Diverging breast and stomach cancer incidence and survival in migrants in The Netherlands, 1996-2009

BACKGROUND

Migrant populations usually experience a health transition with respect to their cancer risk as a result from environmental changes and acculturation processes. We investigated potentially contrasting experiences with breast and stomach cancer risk and survival in migrants to the Netherlands in a retrospective cohort study.

METHODS

Invasive breast (n = 96 126) and stomach cancer cases (n = 24 496) diagnosed 1996-2009 were selected from the population-based Netherlands Cancer Registry. Standardized Incidence Ratios (SIRs) were computed as the ratio of observed and expected cancers. Differences in survival were expressed as relative excess risk of mortality (RER).

RESULTS

Women from Morocco, Suriname and Turkey exhibited a significantly lower risk for breast cancer than native Dutch women (SIR range 0.5-0.9). Relative excess mortality was significantly increased in Surinamese (RER = 1.2, 95% CI 1.0-1.5) patients. The incidence of non-cardia stomach cancer was significantly elevated in all migrants, except in Indonesians, being highest in Turkish males (SIR = 2.2, 1.9-2.6). Cardia stomach cancer appeared to be less frequent in all migrants, being lowest in Surinamese males (SIR = 0.3, 0.2-0.5). Relative excess mortality was significantly lower in patients from the Antilles (RER = 0.7, 0.5-1.0), Suriname (0.8, 0.6-0.9) and Turkey (0.7, 0.6-0.9).

CONCLUSION

The lower incidence rates of breast and cardia stomach cancer in migrants as well as their higher non-cardia stomach cancer rates reflect most likely early life exposures including pregnancy and/or dietary patterns during life-course. While higher relative excess mortality from breast cancer in migrant women might point toward inadequate access and treatment in this group, lower excess mortality from (especially non-cardia) stomach cancer remains to be explained.

Prostate cancer incidence and survival in immigrants to Sweden

PURPOSE

The large international variation in the incidence of prostate cancer (PC) is well known but the underlying reasons are not understood. We want to compare PC incidence and survival among immigrants to Sweden in order to explain the international differences.

METHODS

Cancer data were obtained from the Swedish Cancer Registry. Standardized incidence ratios (SIRs) were calculated for PC in first-degree immigrants by country of birth. The immigrants were classified into four groups by SIR and area of origin. Survival in PC was assessed by hazard ratio (HR) in the four groups. In some analyses, clinical stage of PC was assessed by the tumor, node, and metastasis classification.

RESULTS

The SIR was 0.47 (95% confidence interval 0.43-0.51) for immigrants with the lowest risk, constituting men from Turkey, Middle East, Asia, and Chile. The HR was 0.60 (0.45-0.81) for these men and it was 0.49 if they had stayed 20+ years in Sweden. The SIR in screening detected PC, T1c, was 0.55. Among these men, screening detected PC constituted 34.5% of all PC, compared to 29.0% among Swedes (p = 0.10).

CONCLUSIONS

The results showed that the non-European immigrants, of mainly Middle East, Asian, and Chilean origin, with the lowest risk of PC, also had the most favorable survival in PC. As the available clinical features of PC at diagnosis or the distribution of known risk factors could not explain the differences, a likely biological mechanism through a favorable androgenic hormonal host environment is suggested as an explanation of the observed effects.

Risk of localized and advanced prostate cancer among immigrants versus native-born Swedish men: a nation-wide population-based study

PURPOSE

Prostate cancer (PCa) incidence and prognosis vary geographically. We examined possible differences in PCa risk by clinical risk category between native-born and immigrant populations in Sweden. Our hypothesis was that lower PSA-testing uptake among foreign-born men would result in lower rates of localized disease, and similar or higher risk of metastatic disease.

METHODS

Using the Prostate Cancer database Sweden, we identified 117,328 men with PCa diagnosed from 1991 to 2008, of which 8,332 were foreign born. For each case, 5 cancer-free matched controls were randomly selected from the population register. Conditional logistic regression was used to compare low risk, intermediate risk, high risk, regionally metastatic, and distant metastatic PCa based upon region of origin.

RESULTS

Across all risk categories, immigrants had significantly lower PCa risk than native-born Swedish men, except North Americans and Northern Europeans. The lowest PCa risk was observed in men from the Middle East, Southern Europe, and Asia. Multivariable adjustment for socioeconomic factors and comorbidities did not materially change risk estimates. Older age at immigration and more recent arrival in Sweden were associated with lower PCa risk. Non-native men were less likely to be diagnosed with PCa through PSA testing during a health checkup.

CONCLUSIONS

The risk for all stages of PCa was lower among first-generation immigrants to Sweden compared with native-born men. Older age at immigration and more recent immigration were associated with particularly low risks. Patterns of PSA testing appeared to only partly explain the differences in PCa risk, since immigrant men also had a lower risk of metastatic disease.

Cancer mortality patterns among Turkish immigrants in four European countries and in Turkey

The aim of this study on cancer mortality among Turkish immigrants, for the first time, traditional comparisons in migrant health research have been extended simultaneously in two ways. First, comparisons were made to cancer mortality from the immigrants' country of origin and second, cancer mortality among Turkish immigrants across four host countries (Belgium, Denmark, France and the Netherlands) was compared. Population-based cancer mortality data from these countries were included. Age-standardized mortality rates were computed for the local-born and Turkish population of each country. Relative differences in cancer mortality were examined by fitting country-specific Poisson regression models. Globocan data on cancer mortality in Turkey from 2008 were used in order to compare mortality rates of Turkish immigrants with those from their country of origin. Turkish immigrants had lower all-cancer mortality than the local-born populations of their host countries, and mortality levels comparable to all-cancer mortality rates in Turkey. In the Netherlands and France breast cancer mortality was consistently lower in Turkish immigrants women than among local-born women. Lung cancer mortality was slightly lower in Turkish immigrants in the Netherlands and France but varied considerably between migrants in these two host countries. Stomach cancer mortality was significantly higher in Turkish immigrants when compared to local-born French and Dutch. Our findings indicate that exposures both in the country of origin and in the host country can have an effect on the cancer mortality of immigrants. Despite limitations affecting any cross-country comparison of mortality, the innovative multi-comparison approach is a promising way to gain further insights into determinants of trends in cancer mortality of immigrants.

Excess mortality in women of reproductive age from low-income countries: a Swedish national register study

Background: Cause-of-death statistics is widely used to monitor the health of a population. African immigrants have, in several European studies, shown to be at an increased risk of maternal death, but few studies have investigated cause-specific mortality rates in female immigrants. Methods: In this national study, based on the Swedish Cause of Death Register, we studied 27 957 women of reproductive age (aged 15–49 years) who died between 1988 and 2007. Age-standardized mortality rates per 100 000 person years and relative risks for death and underlying causes of death, grouped according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, were calculated and compared between women born in Sweden and in low-, middle- and high-income countries. Results: The total age-standardized mortality rate per 100 000 person years was significantly higher for women born in low-income (84.4) and high-income countries (83.7), but lower for women born in middle-income countries (57.5), as compared with Swedish-born women (68.1). The relative risk of dying from infectious disease was 15.0 (95% confidence interval 10.8–20.7) and diseases related to pregnancy was 6.6 (95% confidence interval 2.6–16.5) for women born in low-income countries, as compared to Swedish-born women. Conclusions: Women born in low-income countries are at the highest risk of dying during reproductive age in Sweden, with the largest discrepancy in mortality rates seen for infectious diseases and diseases related to pregnancy, a cause of death pattern similar to the one in their countries of birth. The World Bank classification of economies may be a useful tool in migration research.

Designing an intervention to help people with colorectal adenomas reduce their intake of red and processed meat and increase their levels of physical activity: a qualitative study

Background

Most cases of colorectal cancer (CRC) arise from adenomatous polyps and malignant potential is greatest in high risk adenomas. There is convincing observational evidence that red and processed meat increase the risk of CRC and that higher levels of physical activity reduce the risk. However, no definitive randomised trial has demonstrated the benefit of behaviour change on reducing polyp recurrence and no consistent advice is currently offered to minimise patient risk. This qualitative study aimed to assess patients’ preferences for dietary and physical activity interventions and ensure their appropriate and acceptable delivery to inform a feasibility trial.

Methods

Patients aged 60–74 included in the National Health Service Bowel Cancer Screening Programme (NHSBCSP) were selected from a patient tracking database. After a positive faecal occult blood test (FOBt), all had been diagnosed with an intermediate or high risk adenoma (I/HRA) at colonoscopy between April 2008 and April 2010. Interested patients and their partners were invited to attend a focus group or interview in July 2010. A topic guide, informed by the objectives of the study, was used. A thematic analysis was conducted in which transcripts were examined to ensure that all occurrences of each theme had been accounted for and compared.

Results

Two main themes emerged from the focus groups: a) experiences of having polyps and b) changing behaviour. Participants had not associated polyp removal with colorectal cancer and most did not remember being given any information or advice relating to this at the time. Heterogeneity of existing diet and physical activity levels was noted. There was a lack of readiness to change behaviour in many people in the target population.

Conclusions

This study has confirmed and amplified recently published factors involved in developing interventions to change dietary and physical activity behaviour in this population. The need to tailor the intervention to individuals, the lack of knowledge about the aetiology of colon cancer and the lack of motivation to change behaviour are critical factors.

Trial registration

Current Controlled Trials ISRCTN03320951

Regional differences and temporal trends in male reproductive health disorders: semen quality may be a sensitive marker of environmental exposures

The decline in semen quality has been the subject of an animated debate. A recent prospective study now irrefutably shows a decline in semen quality in men from Finland, a country that previously boasted good semen quality. Semen quality has, in some countries, reached a level where a considerable fraction of young men are at risk of fertility problems. Impaired semen quality, testicular cancer, cryptorchidism and hypospadias are risk factors for each other, and the testicular dysgenesis syndrome (TDS) has been put forward to explain the observations. This syndrome implies that the four disease entities share the same patho-physiological etiology caused by disturbed testicular development in early fetal life. It seems likely that the rapid rise in TDS-associated conditions can, at least partly, be explained by environmental factors. Animal studies provide strong evidence that manmade chemicals can disrupt the hormone dependent pathways responsible for fetal gonadal development, subsequently leading to TDS-like symptoms. In humans, fetal exposure to endocrine disrupting substances may play a role, although genetic factors are probably also involved. Recent studies indicate that exposure to endocrine disrupters also in adulthood may affect semen quality and reproductive hormones. Causal relationships are inherently difficult to establish in humans, and a clear connection between the disorders and specific toxicants has not been established. It seems likely that the cumulative effects of various low-dose exposures to endocrine disrupters in our environment are responsible for the adverse effects in the male reproductive system. Semen quality may be the most sensitive marker of adverse environmental exposures, and we suggest that standardized surveillance studies of semen quality are continued or initiated to monitor the combined effects of various preventive actions.

High rates of endometrial cancer among Pacific women in New Zealand: the role of diabetes, physical inactivity, and obesity

PURPOSE

To determine the endometrial cancer rates, and the proportion attributable to diabetes mellitus (DM), physical inactivity, and overweight/obesity, by ethnicity with a focus on Pacific women in New Zealand.

METHODS

Linked census-cancer records (1981-2004) were used to determine incidence rates of endometrial cancer by ethnicity. Health survey data (2006-2007) were used to determine risk factor prevalence by ethnicity. Relative risks for the association between diabetes, obesity, physical inactivity and endometrial cancer were sourced from published studies. Population attributable risk (PAR) methods, with Monte Carlo simulation, were used to estimate the PAR% by ethnicity and applied to 2001-2004 cancer rates.

RESULTS

Pacific women had 2.61 (95 % confidence interval 2.22-3.05) times the endometrial cancer rate of European/Other women pooled over time, and the most rapidly increasing rates over time with the rate ratio increasing from 1.96 (1.14-3.37) in 1981/1986 to 3.78 (3.03-4.71) in 2001/2004 (p for trend = 0.14). Pacific women had the highest PAR% for DM, physical inactivity, and overweight/obesity (63.1 %), followed by Māori (58.6 %) and European/Other (48.6 %). Applying these PAR% to 2001-2004 endometrial cancer rates, the rate ratio comparing Pacific to European/Other endometrial cancer reduced from 3.8 for total cancer (attributable plus non-attributable) to 2.3 for non-attributable cancer, and the rate difference reduced by 79 % from 51 to 11 per 100,000.

CONCLUSIONS

Pacific women have high endometrial cancer rates in New Zealand. Some, but not all, of the ethnic inequalities were explained by measured differences in obesity/overweight, DM, and physical inactivity.

Comparability of cancer identification among Death Registry, Cancer Registry and Hospital Discharge Registry

Registry-based cancer incidence and mortality data are widely used for etiologic research, cancer control and health care monitoring and planning. The complete coverage of all cases is the key criteria of data quality but it is difficult to assess because the alternative sources of data may be flawed. The aim of our study was to examine, at a nationwide level, the completeness of the Swedish Cancer Registry (CR) regarding persons who died of cancer, based on the Cause of Death Registry (DR), and using the Hospital Discharge Registry (HDR) as an additional source of data. Individuals who died of cancer from years 1999 through 2008 recorded in DR were linked to CR and HDR. A total of 190,692 individuals were identified from DR with cancer as the underlying cause of death; the mean identification rate of concordant cancer in CR was 79.8%, depending on tumor site and age at death. Breast, bladder and prostate cancers showed the highest rate of identification, whereas bone, liver and pancreatic cancers showed the lowest rate of identification. CR had no records on 10.6% of cancer cases recorded in DR. Similarly, the identification rate in HDR was 84.5% for concordant cancer and with 9.6% of cases missing. Neither source reported cancers for 3.4% of cancer cases recorded in DR. In conclusion, some 10% of cancer deaths had no cancer records in CR or in HDR, and 3.4% were missing in both sources. The identification rate depended on tumor site, age at death and, to some extent, death outside hospital.

Occupational risk factors for systemic lupus erythematosus: a nationwide study based on hospitalizations in Sweden

OBJECTIVE

To investigate possible associations between occupation and hospitalization for systemic lupus erythematosus (SLE) in a nationwide study.

METHODS

A nationwide database was constructed in Sweden by linking the Swedish Census to the Hospital Discharge Register to obtain data on all first hospitalizations with a primary or secondary diagnosis of SLE in adults during the study period (1970 to 2008). Standardized incidence ratios (SIR) and 95% CI were calculated for different occupations. Two cohorts were defined based on occupational titles recorded in Swedish census data in 1970 and 1980.

RESULTS

A total of 8921 male and 42290 female hospitalizations for SLE were retrieved in individuals aged over 15 years. High education (> 12 yrs) was associated with a lower risk of hospitalization for SLE among both women (SIR = 0.73) and men (SIR = 0.72). Among men with the same occupation in 2 consecutive censuses, increased risks (SIR) > 2.0 were present among artistic workers (2.52); shop managers and assistants (3.63); miners and quarry workers (6.04); shoe and leather workers (6.93); plumbers (2.21); other construction workers (2.08); glass, ceramic and tile workers (4.43); chimney sweeps (4.54); and military personnel (3.01). Among women with the same occupation in 2 consecutive censuses, no occupation was associated with SIR > 2.0.

CONCLUSION

Occupation may carry significantly increased risk of hospital admission for SLE. Especially among men, several occupations were associated with increased risks for SLE.

Prevalence of colonic neoplasia and advanced lesions in the normal population: a prospective population-based colonoscopy study

OBJECTIVE

There are few prospective studies of the prevalence of colonic neoplasia in the normal population. In order to properly evaluate screening-protocols for colorectal cancer in risk groups (e.g., older subjects or those with a family history), it is essential to know the prevalence of adenomas and cancer in the normal population.

METHODS

A prospective population-based colonoscopy study on 745 individuals born in Sweden aged 19-70 years was conducted (mean age 51.1 years). All polyps seen were retrieved and examined.

RESULTS

Out of the 745 individuals 27% had polyps, regardless of kind. Adenomas were found in 10% of the individuals and finding of adenomas was positively correlated to higher age. Men had adenomas in 15% and women in 6% of the cases. Women had a right-sided dominance of adenomas. Hyperplastic polyps were seen in 21% of the individuals. The presence of hyperplastic polyps was significantly positively correlated to the presence of adenomas. Advanced adenomas were seen in 2.8% of the study participants, but no cancers were detected.

CONCLUSION

One in 10 healthy subjects had an adenoma but advanced adenomas were uncommon. Men and women have a different adenoma prevalence and localization. The results provide baseline European data for evaluating colonoscopy screening-protocols for colorectal cancer risk groups, and the findings may have implications for colon cancer screening in the normal, otherwise-healthy population.