New data show cancer rates rising in the Corn Belt states of Iowa, Nebraska, Illinois, Minnesota, Indiana and Kansas while the national trend moves down, and scientists are gathering to untangle a mix of environmental and lifestyle clues that could explain why. A University of Iowa panel and independent analyses of federal cancer registries point to patterns emerging since the mid-2000s, with the gap widening in the 2010s and sharper increases among younger adults. Investigators are weighing soil and water contaminants, pesticide exposure, obesity and drinking habits alongside screening gaps to understand what might be driving these shifts.
The trend caught local attention and prompted a formal inquiry that included national experts on nutrition, epidemiology and environmental health. “The panel came about after they noticed that the trends for cancer incidence were increasing at a faster rate in Iowa than in other states,” which led to a focused look at regional data and potential drivers. That observation set the stage for a deeper dive into multi-decade cancer registries and public health records held by national agencies. The aim was to pin down which cancers are rising, who is affected, and when the divergence from the national pattern began.
Analysts compared cancer incidence from the late 1990s through 2022 using multi-year averages designed to smooth short-term fluctuations, and they excluded the pandemic year 2020 because reporting and diagnoses were unusually disrupted. The result shows that where Midwestern rates once matched the national average, by the 2010s they began to separate, and today residents aged 15 to 49 in the Corn Belt are seeing roughly a five percent higher incidence. These sorts of shifts matter because they can reflect exposures or behaviors that are regional in nature, or failures in screening and prevention that are uneven across states. Researchers emphasize that the pattern is not limited to a single cancer type but includes several that are preventable or detectable early through screening.
On the lifestyle side, investigators are flagging higher-than-average levels of binge drinking and obesity as contributors that compound risk over time. Public health surveys show about 21 percent of adults in Iowa report heavy drinking or binge episodes compared with roughly 17 percent nationally, and state health reports place obesity prevalence in the mid-30s percentage range. Neuhouser and others note that obesity is linked to a long list of cancers and that behavior-driven risks can interact with environmental exposures. “Everyone would like to be able to narrow down cancer risk … to one exposure, but cancer is so complex that it’s usually several factors working together,” which is why multidisciplinary review is essential.
Environmental signals in the Corn Belt raise additional concerns because agricultural practices influence air, soil and water. Decades of fertilizer use have left higher levels of nitrate in groundwater and some of the nation’s higher natural radon readings appear in these soils, and both nitrate and radon have established links to lung and gastrointestinal cancers when exposures are significant. Those pathways are being mapped by state and federal environmental health units as part of the cancer investigations. Local research centers have described the region as a hotspot for contaminant exposures, spurring targeted sampling and health tracking.
Pesticide and herbicide use is another focus, with glyphosate drawing particular scrutiny because of its ubiquity and long-term application across corn and soybean acreage. Dr. Anne McTiernan has reviewed decades of research on glyphosate and cancer risk to look for consistent patterns and plausible biological mechanisms. “Glyphosate, a broad-spectrum herbicide, has been used in the U.S. for decades, and is reported to be the most widely used pesticide globally,” an observation she has emphasized while weighing the totality of epidemiologic and laboratory evidence.
The World Health Organization’s International Agency for Research on Cancer classified glyphosate as “a 2A carcinogen (“probably carcinogenic to humans”), which is the second-highest grade of carcinogen, according to McTiernan. Her summary of studies through 2025 indicates that people with long-term, high exposure—often those working in agriculture—show roughly a 40 percent higher risk of developing non-Hodgkin lymphoma compared with never-exposed individuals. Lab studies that document DNA damage and cellular stress add biological plausibility to the epidemiologic signals, and experts say the combined evidence strengthens a causal interpretation for high, sustained exposures.
Beyond single agents, public health officials emphasize the way multiple risks stack up in communities where farming, drinking patterns and health care access intersect. Screening rates, preventive care availability and local behavioral norms all influence which cancers get diagnosed and how early they are found, and these factors vary across states and counties. Researchers continue to analyze the data to isolate geographic clusters, identify high-risk occupations, and estimate how much each factor contributes to the rising rates. Ongoing surveillance and targeted studies aim to sharpen the picture so policymakers and clinicians can act on the clearest signals.
