Cancer among the Sami--a review on the Norwegian, Swedish and Finnish Sami populations

Elevated colorectal cancer incidence among American Indian/Alaska Native persons in Alaska compared to other populations worldwide

Colorectal cancer (CRC) is a leading cancer worldwide; incidence varies greatly by country and racial group. We compared 2018 American Indian/Alaska Native (AI/AN) CRC incidence rates in Alaska to other Tribal, racial, and international population rates. AI/AN persons in Alaska had the highest CRC incidence rate among US Tribal and racial groups (61.9/100,000 in 2018). AI/AN persons in Alaska also had higher rates than those reported for any other country in the world in 2018 except for Hungary, where males had a higher CRC incidence rate than AI/AN males in Alaska (70.6/100,000 and 63.6/100,000 respectively). This review of CRC incidence rates from populations in the United States and worldwide showed that AI/AN persons in Alaska had the highest documented incidence rate of CRC in the world in 2018. It is important to inform health systems serving AI/AN persons in Alaska about policies and interventions that can support CRC screening to reduce the burden of this disease.

Disparities amidst plenty: a health portrait of Indigenous peoples in circumpolar regions

This paper describes the extent and variation in health disparities between Indigenous and non-Indigenous people within Alaska, Greenland and the northern regions of Canada, Russia and the Nordic countries. We accessed official health statistics and reviewed research studies. We selected a few indicators of health status, health determinants and health care to demonstrate the health disparities that exist. For a large number of health indicators Indigenous people fare worse than non-Indigenous people in the same region or nationally, with the exception of the Sami in the Nordic countries whose health profiles are similar to their non-Sami neighbours. That we were unable to produce a uniform set of indicators applicable to all regions is indicative of the large knowledge gaps that exist. The need for ongoing health monitoring for Indigenous people is most acute for the Sami and Russia, less so for Canada, and least for Alaska, where health data specific to Alaska Natives are generally available. It is difficult to produce an overarching explanatory model for health disparities that is applicable to all regions. We need to seek explanation in the broader political, cultural and societal contexts within which Indigenous people live in their respective regions.

Somatic health in the Indigenous Sami population - a systematic review

The objective of this systematic review was to survey the current scientific knowledge regarding the state of somatic health among the Indigenous Sami people in Norway, Finland, Sweden and the Kola Peninsula in Russia; and assess the quality of the identified studies. A systematic search in the databases Pubmed, EBSCOhost (AMED, Medline, Cinahl) and Svemed was conducted from January 2000, through December 2017. This systematic search identified 399 articles. After screening abstracts, 93 articles were reviewed in full text, 32 of which met the inclusion criteria. The scientific quality of the evidence was rated according to the Newcastle–Ottawa scale. Based on the studies with moderate to high scientific quality, there is evidence for stating that the majority of the Sami included in this review experience good health. Mortality and life expectancy are similar, with only minor differences, to those of a non-Sami population. The cancer risk rate among Sami was lower than that of the general population of Norway, Sweden and Finland. Self-reported myocardial infarction prevalence was similar between Sami and non-Sami, but Angina pectoris was more prevalent among Sami. In Sweden, cardiovascular disease rates were similar between Sami and non-Sami. Musculoskeletal pain symptoms are common among the Sami population, as are obesity and overweight. To conclude, there are knowledge gaps in regard to the somatic health situation of the Indigenous Sami in the circumpolar area, especially in Russia, Finland and Sweden; as current knowledge is mainly based on publications from the SAMINOR study in Norway. No study obtained the highest quality score, suggesting a need to implement longitudinal prospective studies.

The “cancer–cold” hypothesis and possible extensions for the Nordic populations

Cancer incidence is inexplicably high in cold countries. This has been revealed by recent genetic and epidemiological studies. These studies used data from the GLOBOCAN-2012 database, for 186 populations and for a variety of cancer types. Cancer incidence in Nordic people is particularly high for the frequent cancer forms, like breast, prostate and colon cancer. A relationship of cancer with cold is suspected since Inuit and Alaska Indians that live in even more extreme low temperatures have the higher cancer rates in the world. In this article, possible reasons for this phenomenon are discussed. These explanations are related with: evolutionary adaptation to extreme cold, the genetic background of Nordic people, the experimentally proven fast growth and metastasis of tumors at low temperatures, high concentration of certain air pollutants at cold environments, low levels of serum Vitamin D, overdiagnosis by the medical doctors and high quality of the health system in Nordic countries. Lifestyle parameters are not discussed in detail, although these may be equally crucial for cancer risk in cold countries. In conclusion, more studies are needed to elucidate the real causes of this epidemiological pattern.

Measuring cancer in indigenous populations

It is estimated that there are 370 million indigenous peoples in 90 countries globally. Indigenous peoples generally face substantial disadvantage and poorer health status compared with nonindigenous peoples. Population-level cancer surveillance provides data to set priorities, inform policies, and monitor progress over time. Measuring the cancer burden of vulnerable subpopulations, particularly indigenous peoples, is problematic. There are a number of practical and methodological issues potentially resulting in substantial underestimation of cancer incidence and mortality rates, and biased survival rates, among indigenous peoples. This, in turn, may result in a deprioritization of cancer-related programs and policies among these populations. This commentary describes key issues relating to cancer surveillance among indigenous populations including 1) suboptimal identification of indigenous populations, 2) numerator-denominator bias, 3) problems with data linkage in survival analysis, and 4) statistical analytic considerations. We suggest solutions that can be implemented to strengthen the visibility of indigenous peoples around the world. These include acknowledgment of the central importance of full engagement of indigenous peoples with all data-related processes, encouraging the use of indigenous identifiers in national and regional data sets and mitigation and/or careful assessment of biases inherent in cancer surveillance methods for indigenous peoples.

Cancer among circumpolar populations: an emerging public health concern

OBJECTIVES

To determine and compare the incidence of cancer among the 8 Arctic States and their northern regions, with special focus on 3 cross-national indigenous groups--Inuit, Athabaskan Indians and Sami.

METHODS

Data were extracted from national and regional statistical agencies and cancer registries, with direct age-standardization of rates to the world standard population. For comparison, the "world average" rates as reported in the GLOBOCAN database were used.

FINDINGS

Age-standardized incidence rates by cancer sites were computed for the 8 Arctic States and 20 of their northern regions, averaged over the decade 2000-2009. Cancer of the lung and colon/rectum in both sexes are the commonest in most populations. We combined the Inuit from Alaska, Northwest Territories, Nunavut and Greenland into a "Circumpolar Inuit" group and tracked cancer trends over four 5-year periods from 1989 to 2008. There has been marked increase in lung, colorectal and female breast cancers, while cervical cancer has declined. Compared to the GLOBOCAN world average, Inuit are at extreme high risk for lung and colorectal cancer, and also certain rare cancers such as nasopharyngeal cancer. Athabaskans (from Alaska and Northwest Territories) share some similarities with the Inuit but they are at higher risk for prostate and breast cancer relative to the world average. Among the Sami, published data from 3 cohorts in Norway, Sweden and Finland show generally lower risk of cancer than non-Sami.

CONCLUSIONS

Cancer among certain indigenous people in the Arctic is an increasing public health concern, especially lung and colorectal cancer.

Resilience among old Sami women

There is lack of research on old indigenous women's experiences. The aim of this study was to explore how old women narrate their experiences of wellbeing and lack of wellbeing using the salutogenetic concept of resilience. Interviews from nine old Sami women were analysed according to grounded theory with the following themes identified: contributing to resilience and wellbeing built up from the categories feeling connected, feeling independent and creating meaning; and contributing to lack of lack of resilience and wellbeing built up from the category experiencing lack of connectedness. The old Sami women's narratives showed that they were to a high extent resilient and experienced wellbeing. They felt both connected and independent and they were able to create meaning of being an old Sami woman. Having access to economic and cultural capital were for the old Sami women valuable for experiencing resilience. Lack of resilience was expressed as experiences of discrimination, lack of connectedness and living on the border of the dominant society. Analysis of the Sami women's narratives can give wider perspectives on women's health and deepen the perspectives on human resilience and increase the understanding of minority groups in a multicultural world.

Fallout 137Cs in reindeer herders in Arctic Norway

Reindeer herders in the Arctic were among the most heavily exposed populations to the global fallout from nuclear weapons testing in the 1950s and 1960s, due to high transfer of radionuclides in the lichens-reindeer-human food chain. Annual studies of (137)Cs in reindeer herders in Kautokeino, Norway, were initiated in 1965 to monitor radiation doses and follow environmental (137)Cs behavior. The (137)Cs concentrations declined from the peak in 1965 with effective half-times of 6-8 years, only interrupted by a temporary doubling in levels from 1986 to 1987 due to the Chernobyl fallout. During the period of 1950-2010 an average herder received an integrated effective dose from incorporated (137)Cs of about 18 mSv. This dose represents an insignificant increase in the risk for developing cancer. Health studies even show a significantly lower cancer incidence among Sámis and reindeer herders in northern Norway compared to other populations in the same area.

Ethnic discrimination and health: the relationship between experienced ethnic discrimination and multiple health domains in Norway's rural Sami population

OBJECTIVE

Self-reported ethnic discrimination has been associated with a range of health outcomes. This study builds on previous efforts to investigate the prevalence of self-reported ethnic discrimination in the indigenous (Sami) population, and how such discrimination may be associated with key health indicators.

STUDY DESIGN

The study relies on data from the 2003/2004 (n=4,389) population-based study of adults (aged 36-79 years) in 24 rural municipalities of Central and North Norway (the SAMINOR study). Self-reported ethnic discrimination was measured using the question: "Have you ever experienced discrimination due to your ethnic background?" Health indicators included questions regarding cardiovascular disease, diabetes, chronic muscle pain, metabolic syndrome and obesity. Logistic regression was applied to examine the relationship between self-reported ethnic discrimination and health outcomes.

RESULTS

The study finds that for Sami people living in minority areas, self-reported ethnic discrimination is associated with all the negative health indicators included in the study.

CONCLUSION

We conclude that ethnic discrimination affects a wide range of health outcomes. Our findings highlight the importance of ensuring freedom from discrimination for the Sami people of Norway.

The burden of stomach cancer in indigenous populations: a systematic review and global assessment

OBJECTIVE

Stomach cancer is a leading cause of cancer death, especially in developing countries. Incidence has been associated with poverty and is also reported to disproportionately affect indigenous peoples, many of whom live in poor socioeconomic circumstances and experience lower standards of health. In this comprehensive assessment, we explore the burden of stomach cancer among indigenous peoples globally.

DESIGN

The literature was searched systematically for studies on stomach cancer incidence, mortality and survival in indigenous populations, including Indigenous Australians, Maori in New Zealand, indigenous peoples from the circumpolar region, native Americans and Alaska natives in the USA, and the Mapuche peoples in Chile. Data from the New Zealand Health Information Service and the Surveillance Epidemiology and End Results (SEER) Program were used to estimate trends in incidence.

RESULTS

Elevated rates of stomach cancer incidence and mortality were found in almost all indigenous peoples relative to corresponding non-indigenous populations in the same regions or countries. This was particularly evident among Inuit residing in the circumpolar region (standardised incidence ratios (SIR) males: 3.9, females: 3.6) and in Maori (SIR males: 2.2, females: 3.2). Increasing trends in incidence were found for some groups.

CONCLUSIONS

We found a higher burden of stomach cancer in indigenous populations globally, and rising incidence in some indigenous groups, in stark contrast to the decreasing global trends. This is of major public health concern requiring close surveillance and further research of potential risk factors. Given evidence that improving nutrition and housing sanitation, and Helicobacter pylori eradication programmes could reduce stomach cancer rates, policies which address these initiatives could reduce inequalities in stomach cancer burden for indigenous peoples.

Health of Indigenous Circumpolar Populations

Indigenous circumpolar populations have experienced profound transitions in lifeways over the past half-century as a result of economic development. Although there have been positive aspects of this social transformation, most circumpolar groups today have a triple burden of disease, with a modestly elevated infectious disease level, an elevated and increasing burden of chronic conditions such as obesity and cardiovascular disease, and high rates of mental health–related challenges. The health of contemporary circumpolar populations is not easily characterized because of dramatic regional differences that stem from socioeconomic disparities among nonindigenous groups, individual population histories, lifestyle factors, environmental pollution, and underlying biological variation. Overall health and well-being range from excellent among the Sami of Sweden and Norway to extremely poor among marginalized native populations in northern Russia. Circumpolar groups today are not only threatened by continued regional economic development and pollution, but also uniquely vulnerable to global climate change.

Induced abortion on demand and birth rate in Sami-speaking municipalities and a control group in Finnmark, Norway

Objectives

The objective of this study was to analyze the birth and induced abortion on demand (IAD) rate among women in Sami-speaking communities and a control group in Finnmark County, Norway.

Methods

The 6 northern municipalities included in the administration area of the Sami language law (study group) were matched with a control group of 9 municipalities. Population data (numbers, sex and age) were accessed from Statistics Norway. Data on birth rate and IAD during the time period 1999–2009 were derived from the Medical Birth Registry (MBR) of Norway. Data on number of women in fertile age (15–44 years) were obtained from Statistics Norway. Between 2001 and 2008, this age group was reduced by 12% (Sami) and 23% (controls), respectively.

Results

Finnmark County has a high IAD rate and 1 in 4 pregnancies (spontaneous abortions excluded) ended in IAD in the study and control groups. The total fertility rate per woman was 1.94 and 1.87 births, respectively. There was no difference between groups with regard to the IAD/birth ratio (P=0.94) or general fertility rate GFR (P=0.82).

Conclusions

Women in the Sami-majority area and a control group in Finnmark County experienced a similar frequency of IAD and fertility rate.

Survival of Sami cancer patients

Objectives

The incidence of cancer among the indigenous Sami people of Northern Finland is lower than among the Finnish general population. The survival of Sami cancer patients is not known, and therefore it is the object of this study.

Study design

The cohort consisted of 2,091 Sami and 4,161 non-Sami who lived on 31 December 1978 in the two Sami municipalities of Inari and Utsjoki, which are located in Northern Finland and are 300–500 km away from the nearest central hospital. The survival experience of Sami and non-Sami cancer patients diagnosed in this cohort during 1979–2009 was compared with that of the Finnish patients outside the cohort.

Methods

The Sami and non-Sami cancer patients were matched to other Finnish cancer patients for gender, age and year of diagnosis and for the site of cancer. An additional matching was done for the stage at diagnosis. Cancer-specific survival analyses were made using the Kaplan–Meier method and Cox regression modelling.

Results

There were 204 Sami and 391 non-Sami cancer cases in the cohort, 20,181 matched controls without matching with stage, and 7,874 stage-matched controls. In the cancer-specific analysis without stage variable, the hazard ratio for Sami was 1.05 (95% confidence interval 0.85–1.30) and for non-Sami 1.02 (0.86–1.20), indicating no difference between the survival of those groups and other patients in Finland. Likewise, when the same was done by also matching the stage, there was no difference in cancer survival.

Conclusion

Long distances to medical care or Sami ethnicity have no influence on the cancer patient survival in Northern Finland.

A traditional Sami diet score as a determinant of mortality in a general northern Swedish population

OBJECTIVES

To examine the relationship between "traditional Sami" dietary pattern and mortality in a general northern Swedish population.

STUDY DESIGN

Population-based cohort study.

METHODS

We examined 77,319 subjects from the Västerbotten Intervention Program (VIP) cohort. A traditional Sami diet score was constructed by adding 1 point for intake above the median level of red meat, fatty fish, total fat, berries and boiled coffee, and 1 point for intake below the median of vegetables, bread and fibre. Hazard ratios (HR) for mortality were calculated by Cox regression.

RESULTS

Increasing traditional Sami diet scores were associated with slightly elevated all-cause mortality in men [Multivariate HR per 1-point increase in score 1.04 (95% CI 1.01-1.07), p=0.018], but not for women [Multivariate HR 1.03 (95% CI 0.99-1.07), p=0.130]. This increased risk was approximately equally attributable to cardiovascular disease and cancer, though somewhat more apparent for cardiovascular disease mortality in men free from diabetes, hypertension and obesity at baseline [Multivariate HR 1.10 (95% CI 1.01-1.20), p=0.023].

CONCLUSIONS

A weak increased all-cause mortality was observed in men with higher traditional Sami diet scores. However, due to the complexity in defining a "traditional Sami" diet, and the limitations of our questionnaire for this purpose, the study should be considered exploratory, a first attempt to relate a "traditional Sami" dietary pattern to health endpoints. Further investigation of cohorts with more detailed information on dietary and lifestyle items relevant for traditional Sami culture is warranted.

What is known about the health and living conditions of the indigenous people of northern Scandinavia, the Sami?

BACKGROUND

The Sami are the indigenous ethnic population of northern Scandinavia. Their health condition is poorly known, although the knowledge has improved over the last decade.

OBJECTIVES

The aim was to review the current information on mortality, diseases, and risk factor exposure in the Swedish Sami population.

DESIGN

Health-related research on Sami cohorts published in scientific journals and anthologies was used to compare the health condition among the Sami and the majority non-Sami population. When relevant, data from the Sami populations in Swedish were compared with corresponding data from Norwegian and Finnish Sami populations.

RESULTS

Life expectancy and mortality patterns of the Sami are similar to those of the majority population. Small differences in incidences of cancer and cardiovascular diseases have been reported. The traditional Sami lifestyle seems to contain elements that reduce the risk to develop cancer and cardiovascular diseases, e.g. physical activity, diet rich in antioxidants and unsaturated fatty acids, and a strong cultural identity. Reindeer herding is an important cultural activity among the Sami and is associated with high risks for accidents. Pain in the lower back, neck, shoulders, elbows, and hands are frequent among both men and women in reindeer-herding families. For men, these symptoms are related to high exposure to terrain vehicles, particularly snowmobile, whereas for women psychosocial risk factors seem to more important, e.g. poor social support, high effort, low reward, and high economical responsibilities.

CONCLUSIONS

Although the health condition of the Sami population appears to be rather similar to that of the general Swedish population, a number of specific health problems have been identified, especially among the reindeer-herding Sami. Most of these problems have their origin in marginalization and poor knowledge of the reindeer husbandry and the Sami culture in the majority population. It is suggested that the most sustainable measure to improve the health among the reindeer-herding Sami would be to improve the conditions of the reindeer husbandry and the Sami culture.

Health consumption in Sami-speaking municipalities with regard to cancer and radiotherapy

OBJECTIVES

The objective of this study was to document that the Sami people, constituting an ethnic minority in northern Norway, experience an equally available specialist health care service as the one offered to Norwegians in general. We aimed to use cancer and radiotherapy treatment as the instrument to clarify the situation.

STUDY DESIGN

A retrospective registry-based study.

METHODS

The 8 municipalities included in the administration area of the Sami language law were matched with a control group of 11 municipalities. Population data (numbers, sex and age) were accessed from Statistics Norway. Data on cancer incidence, prevalence and survival during the 10-year time period 1999-2008 were derived from the Cancer Registry of Norway (CRN). Five years overall survival was calculated for patients diagnosed in the time period 1999-2003. Furthermore, data on radiotherapy (RT) and treatment intention were recorded for the time period 1999-2008.

RESULTS

The Sami-speaking municipalities had a significantly lower incidence of cancer. Breast (RR 0.82 [95% CI 0.76-0.89]) and lung cancer (females RR 0.55 [95% CI 0.52-0.58], males RR 0.64 [95% CI 0.60-0.68]) were significantly less frequent. The Sami group had experienced a significant increase (Sami 54.5% [95% CI 49.2-61.7], controls 24.1% [95% CI 21.7-26.5]) in the prevalence of cancer during the last 10 years. Five years overall survival was similar among both the Sami and control groups. In both groups, 28% of cancer patients underwent radiotherapy.

CONCLUSIONS

The Sami in northern Norway had a lower risk of cancer but experienced the same use of radiotherapy in their cancer treatment as Norwegians in general.

Diet and lifestyle of the Sami of southern Lapland in the 1930s--1950s and today

OBJECTIVES

To describe the lifestyle of the Sami of southern Lapland 50 to 70 years ago in relation to the present-day Sami and non-Sami populations and, thereby, to provide a basis for future studies of culturally related determinants of health and illness.

STUDY DESIGN

A qualitative analysis, and a quantitative comparison of Sami and non-Sami groups.

METHODS

Semi-structured interviews were conducted with 20 elderly Sami concerning their parents' lifestyle and diet 50 to 70 years ago. Questionnaire data from 81 reindeer-herding Sami, 226 non-reindeer-herding Sami and 1,842 sex-, age- and geographically matched non-Sami from the population-based Västerbotten Intervention Project were analysed by non-parametric tests and partial least squares methodology.

RESULTS

Surprisingly, fatty fish may have been more important than reindeer meat for the Sami of southern Lapland in the 1930s to 1950s, and it is still consumed more frequently by reindeer-herding Sami than nonreindeer-herding Sami and non-Sami. Other dietary characteristics of the historical Sami and present-day reindeer-herding Sami were higher intakes of fat, blood and boiled coffee, and lower intakes of bread, fibre and cultivated vegetables, compared with present-day non-Sami. Physical activity was also a part of the daily life of the Sami to a greater extent in the 1930s to 1950s than today. Sami men often worked far from home, while the women were responsible for fishing, farming, gardening (which was introduced in the 1930-1950 period), as well as housework and childcare.

CONCLUSIONS

For studies investigating characteristic lifestyle elements of specific ethnic groups, the elements of greatest acknowledged cultural importance today (in this case reindeer meat) may not be of the most objective importance traditionally.

Circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in rats

We evaluated the effect of various light/dark regimens on the survival, life span and tumorigenesis in rats. Two hundred eight male and 203 females LIO rats were subdivided into 4 groups and kept at various light/dark regimens: standard 12:12 light/dark (LD); natural lighting of the North-West of Russia (NL); constant light (LL), and constant darkness (DD) since the age of 25 days until natural death. We found that exposure to NL and LL regimens accelerated development of metabolic syndrome and spontaneous tumorigenesis, shortened life span both in male and females rats as compared to the standard LD regimen. We conclude that circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in rats. This observation supports the conclusion of the International Agency Research on Cancer that shift-work that involves circadian disruption is probably carcinogenic to humans.