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| 2. |
- Hemminki, Kari, et al.
(författare)
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Cancer in immigrants as a pointer to the causes of cancer.
- 2014
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Ingår i: European Journal of Public Health. - : Oxford University Press (OUP). - 1101-1262 .- 1464-360X. ; 24 Suppl 1, s. 64-71
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Hemminki, Kari, et al.
(författare)
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Does the Breast Cancer Age at Diagnosis Differ by Ethnicity? A Study on Immigrants to Sweden
- 2011
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Ingår i: The Oncologist. - : Oxford University Press (OUP). - 1083-7159 .- 1549-490X. ; 16:2, s. 146-154
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Tidskriftsartikel (refereegranskat)abstract
- Background. Age-specific incidence rates for breast cancer in low-risk and high-risk ethnic populations differ by age at which the incidence maximum is reached: around 50 years in low-risk populations and over 60 years in high-risk populations. The interpretation of these differences remains unsettled, one line primarily referring to biological differences, the second one to cohort effects of rapidly increasing rates in young populations, and the third one to incomplete registration of cancer in the elderly. Methods. The nationwide Family-Cancer Database was used to analyze standardized incidence ratios (SIRs) and age at diagnosis of breast cancer in female immigrants to Sweden by their region of origin compared with women native to Sweden matched on birth year and other relevant factors. Results. We showed first that the SIRs for breast cancer were lower in many immigrant groups compared with natives of Sweden; women from Turkey had the lowest SIR of 0.45, followed by those from Chile (0.54) and Southeast Asia (0.57). Women from nine regions showed an earlier mean age at diagnosis than their matched Swedish controls, the largest differences being 5.5 years for women from Turkey, 5.1 years for those from Asian Arab and "Other African" countries, 4.3 years for those from Iran, and 4.0 years for those from Iraq. Conclusions. The results show that in many immigrant groups, the diagnostic age is earlier (< 50 years) than in natives of Sweden (> 50 years), suggesting that true biological factors underlie the differences. These factors may explain much of the international variation in breast cancer incidence. Identifying these factors should advance understanding of breast cancer etiology and prevention. The Oncologist 2011; 16: 146-154
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- Hemminki, Kari, et al.
(författare)
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Histology-specific risks in testicular cancer in immigrants to Sweden
- 2010
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Ingår i: Endocrine-Related Cancer. - 1479-6821. ; 17:2, s. 329-334
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Tidskriftsartikel (refereegranskat)abstract
- The changes of cancer incidence upon immigration have been used as an estimator of environmental influence on cancer risk. The previous immigrant studies have indicated that the origins of testicular cancer are at an early age in life, probably in the intrauterine period. We wanted to reexamine the critical periods on histology-specific testicular cancer in sons of immigrants to Sweden. We used the nationwide Swedish Family-Cancer Database to calculate standardized incidence ratios (SIRs) for testicular cancer in sons of parents immigrating to Sweden from low-and high-risk countries compared with the native Swedes. Among the large immigrant groups, the SIRs for sons of two Finnish and Asian parents were decreased if the sons were born outside Sweden. The sons of a Danish immigrant couple showed an increased risk of testicular cancer. The changes in SIR were most systematic for seminoma. The present patterns of testicular cancer risk among sons of immigrants point to the early environmental risk factors, which influence the risk probably after the intrauterine period. These factors appear to influence seminoma risk in a more enduring way than they influence non-seminoma. Endocrine-Related Cancer (2010) 17 329-334
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- Hemminki, Kari, et al.
(författare)
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Liver and gallbladder cancer in immigrants to Sweden.
- 2010
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 1879-0852 .- 0959-8049. ; 46, s. 926-931
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The changes of cancer incidence upon immigration can be used as an estimator of environmental influence on cancer risk. We studied site-specific liver and biliary cancers in first-generation immigrants to Sweden with an aim to search for aetiological clues and to find evidence for indigenous incidence rates. MATERIAL AND METHODS: We used the nation-wide Swedish Family-Cancer Database to calculate standardised incidence ratios (SIRs) in immigrants compared to native Swedes. RESULTS: A total of 1428 cancers were identified in immigrants whose median ages (years) at immigration were 27 for men and 26 for women and whose median diagnostic ages were 64 and 66, respectively. The highest SIRs of 6.7 for primary liver cancer were observed for men from East Asia and sub-Saharan Africa. Increased SIRs were recorded for male immigrants from previous Yugoslavia (1.78), Southern Europe (2.91), Turkey (2.15) and Asian Arab countries (2.89). For gallbladder cancer, only women from the Indian subcontinent (3.84) and Chile (2.34) had increased risk while some Northern European immigrants showed decreased risks. CONCLUSIONS: Primary liver cancer was increased in immigrants from endemic regions of hepatitis B virus infection but also from large regions lacking cancer incidence data, North Africa, Asian Arab countries, Turkey and previous Yugoslavia; these are probably intermediary risk regions for this infection. The consideration of these regions as risk areas would justify active diagnostic and vaccination programs. The increase in gallbladder cancer in Chileans and Indians suggests that some persistent damage was inflicted before emigration, characterisation of which will be a challenge for aetiological studies.
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| 7. |
- Hemminki, Kari, et al.
(författare)
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Preventable breast cancer is postmenopausal
- 2011
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Ingår i: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 1573-7217 .- 0167-6806. ; 125:1, s. 163-167
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer incidence has markedly increased in Western countries for reasons that are not entirely understood. We characterized periodic and age-specific incidence trends of breast cancer in immigrants who migrated from low incidence areas to Sweden. The incidence in immigrants was compared to that in native Swedes and standardized incidence ratios (SIRs) were calculated, based on the Swedish Family-Cancer Database. Age-specific incidence data for low and high incidence populations were obtained from Cancer Incidence in Five Continents IX and NORDCAN. For immigrants from the seven lowest countries/regions 535 breast cancers were identified; the SIRs ranging from 0.45 for Turkish to 0.70 for Greek women. The SIR increased somewhat with the length of stay in Sweden, from 0.55 for stay between 0 and 10 years to 0.59 for a stay of 20+ years. The age-specific incidence curves for these immigrants were superimposable upon the earliest Swedish (year 1960) or Danish (1943) rates. These rates differed from the current Swedish rates by a much lower postmenopausal component. Large incidence differences were also observed between white Californians and immigrants from China and Korea. Our results show that the main difference between high and low incidence areas is in postmenopausal cancer which has increased preferentially during the past century. Immigrants from low risk areas to Sweden show age-specific incidence patterns of Swedes half a century ago. These differences offer opportunities for the identification of factors underlying breast cancer etiology and tools for prevention.
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| 8. |
- Hemminki, Kari, et al.
(författare)
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Prostate cancer incidence and survival in immigrants to Sweden
- 2013
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Ingår i: World Journal of Urology. - : Springer Science and Business Media LLC. - 1433-8726 .- 0724-4983. ; 31:6, s. 1483-1488
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Tidskriftsartikel (refereegranskat)abstract
- 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. 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. 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). 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.
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| 10. |
- Mousavi, Seyed Mohsen, et al.
(författare)
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Age- and time-dependent changes in cancer incidence among immigrants to Sweden: colorectal, lung, breast and prostate cancers
- 2012
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 131:2, s. 122-128
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Tidskriftsartikel (refereegranskat)abstract
- To examine the role of gender, age at immigration and length of stay on incidence trends of common cancers, we studied risk of colorectal, lung, breast and prostate cancers in immigrants to Sweden from 1958 to 2008. The nationwide Swedish Family-Cancer Database was used to calculate standardized incidence ratios for common cancers among immigrants compared to Swedes. Immigrants were classified into high-risk countries when their risk was increased, into low-risk when their risk was decreased and into other when their risk was nonsignificant. Among those who immigrated at younger age (<30 years), we found an increasing trend for colorectal cancer risk in low-risk men and high-risk women. Among those who immigrated at older age (=30 years), a decreasing lung cancer risk in high-risk men and an increasing breast cancer risk in low-risk women were observed. The increasing trend of prostate cancer risk was independent of age at immigration. The risk trends for other immigrants were between the risks of low- and high-risk countries. The gender-specific shifts in cancer risks in immigrants toward the risk in natives indicate a major role of sex, age at immigration and environmental exposures in colorectal and lung cancers risks. In contrast, the unchanged trend of breast cancer among those who immigrated at younger ages and an increasing trend for those who migrated at older ages may suggest a limited effect for environmental exposures, especially at younger age. Our study points out a role of age at immigration on the risk trend of cancer.
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