Study indicates a strong link between socio-economic status and asthma

New research shows Inuit populations in the Canadian Arctic have asthma rates far below Aboriginal people in other parts of Canada, especially those in urban centres.

The study, published recently in the International Journal of Circumpolar Health, says reported cases of asthma in Inuit children was 5%, compared to 12% for all other Aboriginal groups. In Inuit adults, 5.4% of respondents had been diagnosed with asthma, compared to the national average of 11%.

Eric Crighton, lead author of the paper and Geography Professor at the University of Ottawa, says while it's not unusual to see lower rates of asthma in rural areas, that doesn't always mean rural residents are healthier than their urban cousins. While there is less air pollution in rural regions than in cities, in most other determinants of health - such as income, education, housing and the availability of health care - the North scores extremely low.

"It's my personal opinion . . . that it's the limited access to health care that explains this finding. Aboriginal populations are heavily underserved (by health care) all across Canada, but in the North it's a bit more extreme," says Crighton, adding "The biggest determinant of doctor reported asthma is whether you've been to the doctor."

The study is based on an analysis of data in Statistics Canada's 2001 Aboriginal People's Survey. A total of 60,500 adults in northern and southern Canada were surveyed. A child and youth questionnaire was administered to 34,495 respondents (parent, grandparents, etc.).

Crighton also found a relationship between income and incidents of asthma in Aboriginal children and adults. Nineteen percent of children in the lowest income group were reported to have asthma compared to 11% in the highest income group. These figures were similar in the adult Aboriginal population.

But while Crighton says "there is absolutely a link between socio-economic status (SES) and health in general," he adds that some of the SES indicators included in the Stats Canada data were not sufficiently sensitive to make a strong link between SES and asthma. "In the end, many of the SES variables weren't relevant." As an example, he points to an SES indicator that asked respondents if their homes were in need of major repair. "That's a tricky indicator. It might not mean the same thing to all respondents."

Other factors including exposure to second hand smoke, obesity, and chronic maternal stress are important potential risk factors to understand, but unfortunately these were not asked about in the survey

In the end, says Crighton, more research is required to determine a stronger link between SES and asthma, and to discover why there are fewer reported cases of asthma in Inuit populations and in Aboriginal populations living in rural areas and on reserves.