Cancer among circumpolar populations: an emerging public health concern

Abstract

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.

Keywords: Arctic; Indigenous people; Inuit; North American Indians; Sami; cancer; epidemiology; prevention.

Fig. 1

Age-standardized incidence rates of lung cancer among men and women in the Arctic States and their northern regions, 2000–2009. Note: AO=autonomous okrug. All 8 Arctic States (in capital letters) and most of their northern regions are included in the chart – blue refer to Russia and its northern regions, yellow to the Nordic countries and their northern regions, red to Canada and USA and their northern regions, and green to Greenland.

Fig. 2

Age-standardized incidence rates of cervical cancer among women in the Arctic States and their northern regions, 2000–2009. Note: AO = autonomous okrug. All 8 Arctic States and most of their northern regions are included in the chart – blue refer to Russia and its northern regions, yellow to the Nordic countries and their northern regions, red to Canada and USA and their northern regions, and green to Greenland.

Fig. 3

Time trend in lung cancer incidence among circumpolar Inuit and Athabaskan/Dene, 1989–2008.

Fig. 4

Time trend in colorectal cancer incidence among circumpolar Inuit and Athabaskan/Dene, 1989–2008.

Fig. 5

Time trend in breast and cervical cancer incidence among circumpolar Inuit and Athabaskan/Dene women, 1989–2008.

Fig. 6

Risk of cancer by site among circumpolar Inuit relative to the GLOBOCAN world average. Note: Bars above the 1.0 line indicates excess risk among Inuit, whereas bars below the 1.0 line indicates reduced risk. Horizontal axis is in logarithmic scale.

Fig. 7

Lung cancer incidence: Circumpolar Inuit and Athabaskans/Dene compared to global regions.

Fig. 8

Risk of cancer by site among Athabaskans/Dene relative to the GLOBOCAN world average. Note: Bars above the 1.0 line indicates excess risk among Athabaskans/Dene, whereas bars below the 1.0 line indicates reduced risk. Horizontal axis is in logarithmic scale.

Fig. 9

Proportion of non-smokers among the adult population in selected Arctic indigenous populations. Note: Based on data in Results Table 288 of the Survey of Living Conditions in the Arctic www.arcticlivingconditions.org [cited 2014 Dec 20].