Cancer incidence among First Nations adults in Canada: follow-up of the 1991 Census Mortality Cohort (1992-2009).

ABSTRACT

OBJECTIVES: Estimate site-specific cancer incidence rates for a wide range of cancers in First Nations adults in Canada, and compare these with rates in non-Aboriginal adults. METHODS: Responses from persons aged 25 and older to the 1991 Long Form Census were linked to national mortality and cancer databases. First Nations- and non-Aboriginal-specific incidence rates were age-standardized to the world standard population. The sex- and site-specific relative risks (RR) of cancer in First Nations compared to those in non-Aboriginal adults were estimated with Poisson regression. Results were stratified by residence on-reserve (all cancers combined) and region of Canada (four most common cancer sites). RESULTS: Compared to non-Aboriginal adults, First Nations had higher incidence of colon and rectum, kidney, cervix, and liver cancers and lower incidence of prostate, breast, bladder, uterus, ovary, and brain cancers, as well as non-Hodgkin lymphoma, leukemia, and melanoma. First Nations women additionally had higher incidence of stomach, gallbladder, and laryngeal cancers and lower incidence of thyroid cancers compared to non-Aboriginal women. The higher relative incidence of stomach and gallbladder cancers was observed only among First Nations adults who reported living on-reserve. Incidence of lung cancer was similar for First Nations and non-Aboriginal adults nationally, though variation by region of Canada was observed. CONCLUSION: First Nations people in Canada have disproportionately high rates of certain cancers, providing evidence to support public health policy and programming. More research is needed to identify factors contributing to the significantly lower incidence observed for various cancer types. Novel methods for studying disparities in cancer incidence among First Nations people are required to support ongoing cancer control planning and advocacy.