UPDATE: A new study from the city of Montreal provides mounting evidence of the link between income inequality and life expectancy.
The study, released Monday, found life expectancy is six years longer for men in the city's wealthier neighbourhoods than it is in low-income areas. In a comparison of some of the most extreme neighbourhoods, researchers found a disparity of as much as 11 years.
The report urges expansion of the city's social services as a way to narrow the life expectancy gap, including more social assistance payments and an expansion of social housing.
As Canada’s rich-poor divide deepens, critics often point to the tome of research linking income inequality and poor health in countries like the United States as proof that, if unchecked, the growing gap could quite literally make us sick.
But new evidence brings the warning much closer to home.
Looking exclusively at the Canadian-born population, a pioneering study has found that the income differential is already having an adverse effect on the health of residents in cities with the widest gap, increasing the likelihood of succumbing to everything from alcohol abuse to colorectal cancer – regardless of individual income.
“If you are wealthy and you live in an unequal city, you have a higher risk of dying compared to someone who is just as wealthy -- or even potentially less wealthy -- as you, who is living in an area where there is lower extremes of wealth and poverty,” says lead author Nathalie Auger, a public health researcher at the University of Montreal.
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The study, published this year in the Journal of Epidemiology & Community Health, is the first to identify an association between income inequality and mortality in Canada. The findings are based on Census data that tracked 15 per cent of the population aged 25 and over from 1991 to 2000 across 140 Canadian Census Metropolitan Areas.
"To be really sure" of the results, Auger says she used three different indicators of income inequality.
"With each indicator, we got the same results, exactly," she says.
There is, however, one important caveat: the findings do not apply to immigrants.
As Auger explains, when she initially crunched the numbers, the results didn’t make sense; some of the most unequal cities seemed to have the lowest mortality rates. But Auger soon realized why: these cities, places like Toronto and Montreal, also had very high immigrant populations, which she says tend to be young, well-educated, and consequently, “very healthy.”
“We suspected that maybe these immigrants are hiding the underlying associations -- they’re hiding the truth in terms of what we observe between income inequality and health,” she says.
After taking immigrants out of the equation, the findings she uncovered between the income gap and mortality among the Canadian-born population were significant.
Compared to their peers in the most equal cities, women living in highly unequal urban centres were 26 per cent more likely to die of lung cancer, and more than two times more likely to die of transport injuries or drinking-related causes.
Men who lived in cities with a deep income divide, meanwhile, were 50 per cent more likely to die of alcohol-related causes, 20 per cent more likely to die of colorectal cancer and 24 per cent more likely to die of “all other causes,” which includes a number of factors not specifically mentioned in the study.
Says Auger: “There’s something about living in unequal areas that will somehow lead to you dying earlier than you should.”
Though it is difficult to determine precisely what, exactly, that is, Auger suspects that stress could play a role.
“One theory is that people who live in very unequal cities make subtle comparisons of their situation with others around them. This causes stress because you can never be as wealthy. And then [people] adopt unhealthy behaviours to deal with that stress,” she says.
Championed by British epidemiologist Richard Wilkinson, this explanation has gained significant traction since the 2009 release of the book he co-authored with Kate Pickett, The Spirit Level: Why More Equal Societies Almost Always Do Better. Their research has linked income inequality in industrialized countries to everything from increased rates of obesity and infant mortality to drug abuse and mental health problems.
Another possibility, says Dennis Raphael, a health policy and management expert at York University, is that income inequality is a reflection of a series of government policies and economic processes that also contribute to problematic health outcomes.
“You have to understand the income inequality in the context of ‘What are the real things that are happening that are associated with income inequality?’” he says. “The countries that do a bad job [at mitigating income inequality] such as Canada not only squeeze people in terms of income and wealth, but on top of that we don’t provide you with day care and we don’t provide you with affordable housing.”
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Either way, Auger’s findings are part of a growing body of evidence that suggests, when it comes to health in Canada, where you live matters a great deal. Though Auger’s study shows that people of all income brackets suffer from higher mortality rates in unequal cities, those at the bottom end of the income ladder see the greatest health risks.
In Saskatoon, for instance, a 2006 study found that the infant mortality rate was 448 per cent higher in low income neighbourhoods than in the rest of the city. Meanwhile, according to the Toronto-based Wellesley Institute, living in a shelter, rooming house or hotel diminishes the chances of surviving to 75 significantly: to 32 per cent for men; and 60 per cent for women. Those odds are roughly on par with what Canadian women might have expected in 1956. For men, it’s like living in 1921.
All of which, says Nancy Ross, an associate professor of geography at McGill University who co-authored Auger’s study, illustrates the extent to which inequalities are leading to unequal well-being.
“The gap is wide for a country with universal health care and access to education,” she says.
“Every step up the social ladder gives you an extra payback for life expectancy. People should be morally outraged about that.”
10 CHARTS THAT SHOW HOW INCOME INEQUALITY MAY BE MAKING LIFE WORSE