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 whom 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 skeletal remains of nearly 400 people who died before and during the 1918 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.
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.
Using skeletons obtained from the Cleveland Museum of Natural History, which houses more than 3,000 skeletal remains, the researchers examined the shinbones of 369 people who died before and during the 1918 pandemic.
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.
Based on the findings, 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 flu epidemic.
“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 based on 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 the ages of 20 and 40 years of age – the study suggests those who were supposed to be at the prime of their life 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 COVID-19, socioeconomic status, education, access to healthcare, and institutional racism may have played a role.
One of the bigger lessons to be learned from the study, according to the authors, is the danger in public health messaging that suggest 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.”
