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Trevor Hancock: Why did Mary die? Dig deep to find causes

In some ways, public health is like that annoying kid who is always asking: “Why?” Why did this person become sick? Why did they die? It’s a bit like peeling an onion — there is always another layer to the story, another reason why.

In some ways, public health is like that annoying kid who is always asking: “Why?” Why did this person become sick? Why did they die? It’s a bit like peeling an onion — there is always another layer to the story, another reason why.

Every year, we get a list of the leading causes of death, which is not that different between men and women. The leading causes in Canada in 2013 were cancer (30 per cent), heart disease (20 per cent), stroke (five per cent), chronic lung disease, unintentional injuries, diabetes, influenza and pneumonia, and Alzheimer’s disease. Between them, they accounted for almost three-quarters of all deaths.

But what lies behind these numbers — what are the “causes of the causes,” and for that matter, the causes of the causes of the causes? What is left out or overlooked? How complete is the picture we are given? What are we not being told?

We can think about several levels of cause of death. The first, which is what these standard statistics show us, are the clinical diagnoses. But even here there are challenges.

For example, why do we separate heart disease from stroke, when both are forms of vascular disease? And why do we cluster cancers together when it is widely understood that there are many different forms of cancer, with many different causes?

The second level is the behaviours that lie behind the clinical cause of death. Smoking, alcohol or drug use, physical inactivity, unhealthy eating, dangerous driving — the usual litany of unhealthy behaviours that governments and others like to scold us about and encourage us to change. Usually, these are framed as “lifestyle choices” and personal responsibility.

Yet these risk behaviours are embedded in and shaped by the third level of causes — our family, school, workplace and community environments, which shape and might constrain us socially and physically. We are also shaped by our built environments, where we spend the vast majority of our time and where we are car-dependent and inactive, and largely separated from nature. And we are influenced as well by our community’s social and cultural norms; some religious communities, for example, reject childhood immunization.

We are also subject to enormous commercial pressures in the shape of advertising, much of which encourages unhealthy behaviours (check out the food and drink ads, or the driving behaviour shown in most car ads these days), and we are buffeted by economic pressures that can lead to unemployment or low wages, debt, stress, and even hunger and homelessness.

Indeed, we have a mountain of evidence that poverty and poor education result in large inequalities in health and underlie many deaths. We can think of all of these as risk conditions or risk environments, which in turn facilitate and support risk behaviours. But none of these upstream causes of death appear in the official statistics, which means they don’t get the attention they deserve.

So it is the role of public health to raise these more profound and important questions and push for solutions at a community and societal level.

This can get complicated. Consider Mary, who died of a stroke: Why did she die? Because she had high blood pressure that was not detected or, if it was, was not well controlled, perhaps because she is a woman and lived in a rural or low-income community or on a reserve, where health care is less accessible. Or perhaps she could not afford the medication.

But why did she have high blood pressure in the first place? A genetic predisposition? Obesity? A high-salt diet? Canadian diets are much too salty, and the Canadian food industry has resisted efforts to regulate salt content. A stressful life and work situation? Some combination of all these, and more?

So what did Mary die of: A stroke? High blood pressure? A high-salt diet? A stress-filled life? Inadequate health care? Rural life? Poverty? Only the first of these will show up in the standard statistics, which tells us what someone died from — but not why.

Which is why public health keeps asking: “Why?” Because if we can understand why people get sick or injured or die, maybe we could prevent it from happening.


Dr. Trevor Hancock is a professor and senior scholar at the University of Victoria’s school of public health and social policy.

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