In Iowa, Researchers Press for More Scrutiny of the Link Between Big Ag and Cancer Risk

Iowa has a cancer problem: over 20,000 people are expected to be diagnosed with cancer in the next year, with over 6,000 likely to die from the disease. One of the most frequently cited reports in the state is produced by the Iowa Cancer Registry, which has historically refrained from mentioning agriculture as a potential factor in increasing cancer risk. Yet farming is the dominant industry in the state — over 85 percent of the land is devoted to agricultural use and millions of animals are raised on factory farms contributing to environmental pollution. A new initiative, co-developed by The Harkin Institute at Drake University and the nonprofit Iowa Environmental Council, aims to fill this gap and hone in on the role agriculture plays in increasing cancer risk. The initiative was announced at a conference on water quality, held at The Harkin Institute on April 16.

“Even though there are lots of groups talking about studying the high cancer rates, there are some groups that want to limit what we’re looking at when we’re having these conversations,” Adam Shriver, Director of Wellness and Nutrition Policy at The Harkin Institute, said at the conference. “They might want to look at personal behaviors like going to tanning beds or smoking or drinking. And we feel like there’s a really important part of the conversation that’s being left out.”

While behaviors like smoking and binge drinking are linked to higher cancer risk, the new initiative wants to see the link between agriculture and cancer investigated with the same rigor, especially given the prominent role of industrial animal agriculture in Iowa.

The overwhelming majority — 99 percent — of farmed animals in the U.S. are raised in factory farms. In Iowa, there are almost 124 million farm animals at any given time — around 55 million chickens, 53.4 million hogs, 11.5 million turkeys and 3.7 million cattle and cows. Manure spills are commonplace: a recent report by Food and Water Watch found that from 2013 to 2023, there were 179 documented manure spills that killed almost 2 million fish.

Sarah Green, Executive Director of the Iowa Environmental Council, tells conference attendees that Iowa’s cancer rate is not the only outlier statistic about the state. “Iowa has the most factory farm waste of any other state in the country. Iowa has more concentrated animal feeding operations than any other state in the country. Iowa is among the top five states with the highest industrial pesticide use,” she said. “What role do these factors play in Iowa’s cancer rates? What else might be at play?”

In Iowa, waterways are just as impaired as the health of its residents. Almost 2 million fish were killed from the manure spills that occurred in Iowa between 2013 and 2023. The 179 spills were documented throughout the state, with a major hotspot for spills in Iowa’s northwest corner, where hog and other livestock operations are especially dense. Earlier this year, the group reported that Iowa factory farms produce more waste than any other state, at 109 billion pounds of manure annually, based on U.S. Department of Agriculture data. In March, just one manure spill in northeast Iowa killed over 100,000 fish.

For the new initiative, researchers will conduct a review of existing scientific studies and reports for what the research shows (and what it doesn’t) about the connection between agriculture, both row crop and livestock operations, and cancer in the state. The next step is to determine whether there is sufficient evidence based on the review to recommend stronger public health policy.

The project will also host 15 listening sessions around the state to allow Iowans to “share and record their lived experiences with cancer,” Green said. Public awareness is at the heart of the project. “This entire initiative is about each of you and about Iowans, making people’s lives better, giving families more years to make memories together, helping Iowans from all walks of life have healthier, longer futures in our state,” Green said. “The cancer crisis touches every single county in Iowa.”

The initiative is funded by the Walton Foundation, which provides funding to organizations working to protect rivers, “oceans and the communities they support,” as well as philanthropic organizations Builders Vision and Grace Communications and Iowa Radiology, a radiology imaging practice. Disclosure: Builders Vision and Grace Communications are donors to Sentient; donors have no say over Sentient’s editorial coverage or content.

In an email to Sentient, Jim Larew, legal counsel for the nonprofit environmental advocacy group Driftless Water Defenders, praised the new initiative, noting “those holding visible and prominent positions in cancer research in Iowa” have focused their attention on binge drinking, making no mention of industrialized agriculture. A more “objective” review is necessary, he wrote.

“Established institutions have a tendency to avoid naming environmental causes of cancer, which normally can be addressed by policy changes and, instead, point to behavioral contributors to new cancers. Such tendencies have the effect of insulating the investigating institutions from intense political pressures exerted by powerful industrial-agricultural oligarchs,” Larew wrote.

Shriver told Sentient in an email that the plan is to have the report on the literature review completed by fall of this year.