DENVER – It’s been a long-held assumption that the influenza pandemic that decimated a fifth of the world’s population more than a hundred years ago went after everyone – the young, the old, and even those who the flu doesn’t normally kill. But new research out of CU Boulder suggests that conventional wisdom may not be true, after all.
Examining the shinbones of 369 people in the Cleveland area who died before and during the 1918 flu pandemic, researchers from CU Boulder and McMaster University in Ontario, Canada, found that those who suffered chronic illness, nutritional deficiencies, and “other environmental and social stressors” were nearly three times more likely to die when confronted with a novel virus than those who did not experience such conditions.
Looking at the shinbones of the dead is a legitimate method to assess the frailty of a person because any sign of disease will cause tiny bumps to develop in this area of the skeletal system, so things like trauma, infection, stress or malnutrition can be gleaned from their study, according to a news release from CU Boulder.
The authors concluded that the frailest in the population, based on their bone lesions, were 2.7 times more likely to have died during the 1918 pandemic.
The results, published Monday in the journal Proceedings of the National Academy of Sciences (PNAS), “suggest that there was some underlying source of frailty among the victims of the 1918 flu,” according to the authors.
“This idea that the 1918 flu killed healthy young people is not supported by our findings,” said Sharon DeWitte, a professor of anthropology at CU Boulder who specializes in bioarchaeology — the study of human history from material remains found at archeological sites. “It may be one of those ideas that begins as folk wisdom and gets reproduced in the literature over and over until it becomes canon. We wanted to take a step back and ask: Do we really know what we think we know?”
While the 1918 flu pandemic did kill a lot of people, among them millions of men between 20 and 40 years old, the study suggests those who were supposed to be at their healthiest but who nonetheless ended up dying after contracting influenza had prior health problems to begin with, according to Amanda Wissler, an assistant professor of anthropology at McMaster University in Ontario and one of the co-authors of the study.
The authors do caution, however, that the sample size was small and the specimens were all from the Cleveland area, so they “may not fully reflect national realities,” according to a news release from CU Boulder.
The researchers suspect that, like with coronavirus pandemic, socioeconomic status, education, access to healthcare, and institutional racism may have played a role in their outcomes following infection.
One of the bigger lessons to be learned from the study, according to the authors, is the danger in public health messaging that suggests everybody is equally likely to get sick from any given infection they encounter.
"What we have learned is that in future pandemics there will almost certainly be variation between individuals in the risk of death,” said DeWitte. “If we know what factors elevate that risk, we can expend resources to reduce them — and that’s better for the population in general.”
