Crisis or catastrophe: Research analyzes mortality rates

November 29, 2013 by Don Campbell, University of Toronto
From left, UTSC's Sotirios Damouras, Lianne Tripp and Associate Professor Larry Sawchuk

New research from the University of Toronto Scarborough shows that when it comes to defining what makes an event catastrophic in terms of the death rate—whether it's an outbreak of war, famine, disease and even extreme weather—the devil can be found in the demographic details.

"There is misconception about what makes an event a crisis or worse because there is no standard approach in determining normal over a period of time," says Larry Sawchuk, an associate professor in UTSC's Department of Anthropology. "We wanted a technique that can be used to determine qualitatively whether an event fits a consistent pattern of mortality or if it's something more excessive."

Sawchuk, along with graduate student Lianne Tripp and UTSC statistics lecturer Sotirios Damouras—who developed the statistical technique used in the research—devised a method to differentiate a crisis from a catastrophe.

Using from 1825-2011 for Gibraltar, and from 1827-1993 for Malta, they were able to determine that only a limited number of events could be called a crisis or worse.

Mortality rates of the two former British colonies of Gibraltar and Malta were selected because the highly-trafficked port cities both shared a Mediterranean climate, overcrowded populations and deficiency in sanitary infrastructure and public hygiene, while still maintaining a tradition of reliable records-keeping over a long period of time.

According to their research, events that could appropriately be deemed a crisis include outbreaks of yellow fever and influenza in Gibraltar, as well as cholera outbreaks and casualties during the Second World War in both regions. According to their statistical scale, the 1918 influenza epidemic didn't even qualify as a crisis in Malta; while there was a rise in mortality rates, it wasn't nearly as high as other places in the world.

"That event was universally considered to be a devastating disease wherever it hit. But in Malta that wasn't the case," says Tripp. "By applying this method it may be shown that this epidemic and others were not as devastating in certain regions as once thought."

The other benefit of the model is that it can be applied to events that occurred in different periods of time; all that is needed is population data and the recorded number of deaths, says Sawchuk.

They also found unusual events in which the mortality rate was lower than expected. In Malta, following the Second World War, health officials were baffled by stable mortality rates despite poor nutrition, overcrowding and the lack of sanitation caused by the war.

"Conditions were awful. Everything bad that could happen to a population to promote death took place in Malta during the war, but what happened was just the opposite and quite extraordinary," says Sawchuk.

Their research found examples of what anthropologists call the harvesting effect, which occurs following a high mortality event and is characterized by a period of lower than normal mortality. This happens because those who are vulnerable, such as the sick, weak or elderly, die during the event. They discovered this took place following the 1865 cholera epidemic in Malta and Gibraltar, and the 1951 influenza outbreak in Gibraltar

"Mortality events are highly variable over time and space, so it's important to have something objective to measure it," says Sawchuk.

He points to the recent SARS and H1N1 outbreaks that many were calling a crisis. While they had significant economic consequences, from a demographic standpoint there was no evidence to support it was a crisis.

"If you are into crafting policy it's important to know this because if an illness breaks out it's very hard to predict the consequences," says Sawchuk.

The research will be published in the upcoming edition of the American Journal of Physical Anthropology and is currently available online.

Explore further: 2009 pandemic flu death toll much higher than official worldwide estimates

Related Stories

2009 pandemic flu death toll much higher than official worldwide estimates

November 26, 2013
A research team consisting of more than 60 collaborators in 26 countries has estimated the global death toll from the 2009 outbreak of the H1N1 virus to be 10 times higher than the World Health Organization's count, which ...

Crime associated with higher mortality rates

November 6, 2013
The new study, published in the journal PLOS ONE shows that people with drug-related criminal records in Norway have a mortality rate that can be up to 15 times higher than people with no criminal record. Also, people with ...

Behavior change may have the greatest influence on waves of influenza outbreak

July 9, 2013
Three waves of the deadliest influenza pandemic in history, known as the Spanish flu, hit England and Wales in 1918, just as World War 1 was coming to an end.

Background mortality rates key to accurate reporting of vaccine safety risks

June 11, 2013
In a study using the Vaccine Safety Datalink (VSD), investigators analyzed four years of data and determined that background mortality rates (rates of death irrespective of cause) are crucial in interpreting the numbers of ...

New estimates give updated count of Iraq war deaths between 2003 and 2011

October 15, 2013
During the U.S.-led invasion and occupation of Iraq from 2003 to 2011, for every three people killed by violence, two died as a result of the collapse of the infrustructure that supports health care, clean water, nutrition, ...

Dysentery epidemic killed many in the 1700s-1800s

October 25, 2012
In the 1700s-1800s, dysentery was a disease causing many deaths. In fact, in some areas in Sweden 90 percent of all deaths were due to dysentery during the worst outbreaks. A new doctoral thesis in history from the University ...

Recommended for you

Best of Last Year—The top Medical Xpress articles of 2017

December 20, 2017
It was a good year for medical research as a team at the German center for Neurodegenerative Diseases, Magdeburg, found that dancing can reverse the signs of aging in the brain. Any exercise helps, the team found, but dancing ...

Pickled in 'cognac', Chopin's heart gives up its secrets

November 26, 2017
The heart of Frederic Chopin, among the world's most cherished musical virtuosos, may finally have given up the cause of his untimely death.

Sugar industry withheld evidence of sucrose's health effects nearly 50 years ago

November 21, 2017
A U.S. sugar industry trade group appears to have pulled the plug on a study that was producing animal evidence linking sucrose to disease nearly 50 years ago, researchers argue in a paper publishing on November 21 in the ...

Female researchers pay more attention to sex and gender in medicine

November 7, 2017
When women participate in a medical research paper, that research is more likely to take into account the differences between the way men and women react to diseases and treatments, according to a new study by Stanford researchers.

Drug therapy from lethal bacteria could reduce kidney transplant rejection

August 3, 2017
An experimental treatment derived from a potentially deadly microorganism may provide lifesaving help for kidney transplant patients, according to an international study led by investigators at Cedars-Sinai.

Exploring the potential of human echolocation

June 25, 2017
People who are visually impaired will often use a cane to feel out their surroundings. With training and practice, people can learn to use the pitch, loudness and timbre of echoes from the cane or other sounds to navigate ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.