Study finds link between rise in cost of living and a spike in tuberculosis death rates

Microscopic bacteria.

Don Campbell

New U of T Scarborough research finds that a rise in the cost of living experienced during times of crisis can lead to a spike in tuberculosis (TB) mortality rates, especially for women. 

“During times of great stress women were at greater risk, and the likely reason is because of traditional gender roles,” says Lianne Tripp, an Assistant Professor at UNBC and former PhD student in U of T Scarborough’s Department of Anthropology.

Using 20th century economic and demographic data from Malta and the nearby island of Gozo, Tripp and former supervisor Professor Larry Sawchuk found a noticeable relationship between a rise in the cost of living and increased rates in deaths from TB.

“In Malta during the First World War, the 1918 influenza pandemic and the end of the Second World War variations in the cost of living explains about 61 per cent of the variation in TB death rates,” says Tripp.

While female TB death rates were higher in general, it was especially heightened during times of extreme hardship.

“Women were the ones taking care of the sick, were more likely to be spending time indoors in confined spaces, and more likely to be immunocompromised by sacrificing their diets,” she says.  

TB is an infectious disease caused by a bacterium that is spread through the air. It kills almost 2 million people annually across the globe – about 95 per cent of fatal cases occurring in developing countries – making it the world’s deadliest infectious disease.

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Assistant Professor Lianne Tripp and Professor Larry Sawchuk. (Photo by Ken Jones)

As Sawchuk notes, TB is opportunistic and often surfaces in poor living conditions like overcrowded housing, poor nutrition or lack of food, as well as other population stressors.

“Malta during the First World War and at the end of the Second World War were full of these types of stressors,” he says.  

Not only did the small island have some of the highest rates of urban density and overcrowding in Europe at the time, it was also heavily reliant on imports to feed its population, notes Tripp. When imports dropped dramatically during the war and the cost of housing shot up, it created a perfect storm of conditions that put its already precarious population in a very vulnerable position.  

Interestingly, Gozo did not experience the same spike in TB mortality rates despite being close to Malta. This was likely due to its relative independence compared to Malta.

“Gozo was more isolated than Malta, had a mostly agrarian and self-sufficient economy and had no involvement in the war, so this meant they had limited exposure to TB,” she says. 

The study, which is published in the journal PLOS ONE, also uncovered evidence of the harvesting effect that occurred following TB outbreaks when the mortality rates dropped to lower rates than normal. Sawchuk’s past research explored the phenomenon, which occurs when those who are vulnerable such as the sick, weak or elderly, die during a disease outbreak. 

Sawchuk adds the research may be of interest not only to anthropologists but also those interested in how diseases wax and wane over time.

“You’re seeing this more in medical literature and that is a realization diseases don’t exist in a vacuum, that they can simply be explained as a microorganism in humans,” says Sawchuk.

“The cultural, economic and ecological factors that affect disease mortality rates also need to be carefully considered.”