The lower prevalence estimates among Aboriginal people in the North compared to those in the South obtained from the APS 2006 are comparable to those from other surveys.6,7
In Tjepkema's analyses of CCHS 2000/01,6
the prevalence for Aboriginal people in the North is 10% while that in the South is 19% for rural residents and 20% for urban residents; Lix et al. obtain a prevalence of 12% in the North and 20% in the South from the CCHS 2005/06.7
Both these studies also show that the prevalence among Aboriginal people is higher than non-Aboriginal people in the South but not in the North. Note that both the CCHS and APS cover the same Aboriginal groups—off-reserve First Nations, Inuit and Métis. Although less access to specialist care may be responsible for the lower detection rate of arthritis in the North, the prevalence of arthritis is based on self-report and not on clinically verified diagnoses by rheumatologists; further, as a chronic disease arthritis is likely to have been diagnosed sometime in the past over the long term even with limited specialist health care.
In surveys such as the APS, CCHS and RHS, self-reports under the rubric "arthritis and rheumatism" lack clinical accuracy. These self-reports are also limited by the inability to differentiate between different types of arthritides—rheumatoid arthritis, osteoarthritis, etc. However, as a tool for assessing population health and the need for health care, such crude measures are nevertheless useful, particularly to describe the patterns in different population subgroups.
The lower prevalence of arthritis among Aboriginal people in the North can also be attributed to the high proportion of Inuit in the population. (According to the 2006 Census, approximately 54% of Aboriginal residents of the northern territories report some Inuit ancestry, compared to 4% of Aboriginal people in Canada as a whole.14
) A lower prevalence of arthritis among Inuit relative to other Aboriginal people has been shown nationally in APS 20019
and CCHS 2000/01.6
In this study we demonstrate that, within the North, the prevalence of arthritis among all Aboriginal groups—Inuit, First Nations, and Other—is also lower than the corresponding group in the South ().
It is unclear as to why Canadian Inuit have lower prevalence of arthritis than First Nations people. The self-reported arthritis rubric is a mixed bag of clinical entities with different etiologies. A review of North American indigenous populations found that Inuit tend to have high rates of spondyloarthropathies whereas Native Americans have high rates of rheumatoid arthritis.1
A study based on clinical records indicates that the Inupiat in the Alaska North Slope region (who are culturally and linguistically related to the Inuvialuit in the Northwest Territories) have high rates of rheumatoid arthritis compared to some Native American tribes, and much higher than the Yupik in western Alaska.15
A recent study from Alaska that estimated the prevalence of self-reported and clinically undifferentiated arthritis showed that it is higher among Alaska Natives than the general U.S. population, but the Alaskan sample is a mix of Yupik and Native American tribes in the southeastern part of the state.16
Aboriginal people suffering from arthritis have unfavourable health profiles; they are more likely to be daily smokers, be obese and have concurrent chronic diseases, although the magnitude differs between the North and South, reflecting the background prevalence of these associated traits and conditions. Arthritis can limit the opportunity for employment, although this survey does not provide evidence that the lower employment rate is the direct result of the disease.
As expected, Aboriginal people with arthritis are more likely to utilize the health care system, with higher proportions reporting visits to physicians, nurses and traditional healers. The pattern of use reflects the different systems in place in the North and South. We cannot, however, determine if the higher health service use is the direct result of arthritis, but it is a plausible explanation given the nature of the disease, the presence of other risk factors such as smoking and obesity, and co-morbidities. In the North, primary care is predominantly delivered by nurses in health centres in the communities, and individuals have only periodic contact with visiting physicians. For many, visits to specialists such as rheumatologists requires air travel away from home.
Further research is required to explore North-South disparities in the burden of arthritis in Aboriginal populations. Also needed are more refined diagnoses, including rheumatoid arthritis, osteoarthritis and other musculoskeletal disorders, as well as separate analyses of Inuit and First Nations samples, which are sufficiently large within the North. Aboriginal-specific findings on arthritis and other chronic diseases, as well as recognition of regional differences between North and South, will enhance program planning and help identify new priorities in health promotion. The creation and transmission of quality evidence to appropriate stakeholders to ensure uptake and application of study findings will help reduce health disparities.