Pesticides may have shortened human lifespan in areas targeted by cicadas in the early 20th century

A cicada viewed from the front

As millions of Americans brace for a rare simultaneous emergence of two cicada broods this summer, new research out of the La Follette School reveals how cicada-targeting pesticides used in the early 20th century might have shortened Americans’ lifespans. 

The paper, co-authored by Jason Fletcher of the La Follette School, is the first to evaluate exposure to pesticide on old-age mortality. It adds to the understanding of the long-term effects of in-utero and early-life exposure to environmental factors. In the case of pesticides that were used in the early 20th century, Fletcher’s research finds that males born in years when cicadas emerged and in areas that required pesticides had shorter lives by roughly 2.2 months. That number rose to nearly a year for males whose fathers were farmers, leading to direct farm exposure while young. 

“With cicadas in the headlines, this is a good time to reflect on how the environments we create for ourselves can have unintended consequences far down the line, and how we must anticipate these effects much better,” Fletcher says. “This paper is looking at the past, but as we see cancer rates skyrocket and increasingly find microplastics in the human body, I think it is as relevant as ever today.” 

Fletcher and his co-author, Hamid Noghanibehambari from Austin Peay State University and an affiliate of UW-Madison’s Center for Demography of Health and Aging, focus on males born between 1925-1940. By using Social Security Administration death records from 1975-2005 that were linked to the 1940 US census, they identified counties and years in which cicadas emerged, and then compared areas by abundance of tree crops. Cicadas damage tree crops but not row crops, so pesticides were used to prevent significant damage to apple orchards and other tree crops during cicada emergences, while areas with row crops such as corn were left untreated. 

Agrichemicals such as pesticides were rapidly evolving during the late 19th and early 20th centuries as the industry modernized and began innovating with synthetic pesticides. Several of the pesticides in use at the time included now-banned ingredients such as arsenic and lead arsenate. Although lead arsenate has been eliminated from pesticides for decades, researchers believe that millions of acres of land in the United States remain contaminated. 

Fletcher’s research found approximately 300,000 males who met their criteria of in-utero exposure to cicada-targeting pesticides. They calculated that taken together, these pesticides may have accounted for 55,000 years lost to premature death. They also extrapolated this number for all croplands and pesticides to find 1.2 million years lost to in-utero exposure to pesticide use for American males born between 1925-1940. Drawing on statistical modeling, they also calculate that this early mortality among a whole generation has resulted in a cumulative loss of about $1.1 trillion. 

“Two months doesn’t seem like much on an individual level, but when you aggregate these small effects for a whole group, you see how large of an impact something like pesticide use can have on public health,” Fletcher says. “And these effects are in addition to exposure to many other environmental factors that may also decrease longevity.” 

Among the policy implications highlighted by Fletcher, he recommends that policymakers focus on populations at risk and implement targeted initiatives, rather than focusing solely on eliminating or reducing pesticide use. Additionally, he encourages policymakers and public health practitioners to reduce the long-term negative impacts of these types of exposures by recognizing the affected populations and working to find ways to alleviate the effects throughout their lives. 

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