04
Feb
Data from Agricultural Health Study Associate Diabetes with Pesticide Exposure
(Beyond Pesticides, February 4, 2026) Using data from the Agricultural Health Study (AHS) database launched in 1993 by the National Cancer Institute and the National Institute of Environmental Health Sciences, research study results “show greater diabetes risk“ from exposure to organochlorine, organophosphate, and carbamate insecticides, phenoxy and other herbicides, and the fumigant carbon tetrachloride/disulfide exposure. The study, published in Environment International, evaluated nearly 4,000 diabetes cases drawn from AHS follow-up surveys between 1999 and 2021.
Results
Researchers found evidence of an association between 18 pesticide active ingredients and diabetes. These included two phenoxy herbicides, 2,4,5-T and 2,4,5-TP, and seven organochlorine insecticides (DDT, aldrin, dieldrin, chlordane, heptachlor, toxaphene, and lindane). While all these organochlorine pesticides are banned for use in the U.S. (with the exception of pharmaceutical uses of lindane), legacy residues of the chemicals and/or their metabolites continue show up in the environment, food, and the human body, and 2,4,5-T and its TCDD dioxin contaminant has multigenerational effects.
There was exposure risks among other pesticides were identified as well, including:
- 3 organophosphate insecticides (diazinon, malathion, and phorate);
- 2 carbamate insecticides (carbofuran and carbaryl);
- 3 other herbicides (butylate, metribuzin, and chlorimuron ethyl); and
- the fumigant carbon tetrachloride/disulfide.
The median age of diagnosis was 66 years old, with 98 percent of cases identifying as male and non-Hispanic white, 46 percent qualifying as obese, and 41 percent qualifying as past smokers. For further details, please see Sections 3.1 to 3.3.
Background and Methodology
The Agricultural Health Study pulls from approximately 52,394 “licensed pesticide applicators enrolled in 1993-1997. Participants were re-contacted in four follow-up surveys (Phases 2–5: 1999–2003, 2005–2010, 2013–2015, and 2019–2021), and the eligible study sample included those who completed at least one follow-up survey response on diabetes (N=39,197 applicators).”
Diabetes risk association was tested for “ever-use” and “intensity-weighted lifetime days (IWLD) use.” Ever-use pesticide data refers to a Yes/No of whether the applicator had used the pesticide since the previous conducted survey, whereas IWLD use refers to the number of days a pesticide was used multiplied by the concentration applied since the previous conducted survey. “In the analysis sample, 91.2% of respondents had [“ever-use”] exposures updated in 1999–2003, 4.8% were missing exposures in 1999–2003 but were updated in 2005–2010, leaving 4.0% missing updated exposure data among those with incident diabetes or at end of follow-up in 2013–2015 or 2019–2021,” say the authors. They continue: “Intensity-weighted lifetime days (IWLD) of pesticide use were derived from cumulative lifetime days (days per year times the years of use) for 22 pesticides listed on the enrollment questionnaire and 28 pesticides with additional data on the take-home survey, and updated for pesticides still in use by the first two follow-up surveys, weighted by a score incorporating application practices and use of personal protective equipment impacting potential exposure level.”
The authors declare that “[a]ssociations were not confounded by BMI and weight gain,” contributing to the robustness of the analysis. For further details on the methodological approach and statistical analysis, please see Sections 2.1 through 2.5. Researchers for this study were based at the National Institute of Environmental Health Sciences and National Cancer Institute at the National Institutes of Health, University of Texas, and DLH Corporation, a research consulting group. In terms of conflict of interest, “the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.”
Previous Coverage
A systematic review of studies on pesticides as endocrine-disrupting chemicals (EDCs) on body weight, published in Biomedicines, evaluates 36 clinical and preclinical studies and links their agricultural use to obesity. Endocrine disruption and obesity are public health concerns, and there is a wide body of science linking pesticide exposure to these effects (see more here). “Obesity is considered to be a worldwide pandemic that leads to an increase in medical costs and thus becomes a public health problem,” the researchers state. They continue, “[Obesity] is also associated with the increased production of environmental chemicals, also called environmental obesogens, used mainly in agriculture, as disease vector control, helping to prevent harmful effects caused by fungi, bacteria, or even pests, using pesticides, insecticides, and herbicides, or endocrine disruptors (ED), which interfere in different processes.”
In analyzing five human cross-sectional studies, 24 animal studies, and seven in vitro studies published since 2000, the authors investigate how environmental and dietary pesticide exposure is associated with anthropometric parameters, such as weight and body mass index (BMI), and metabolic changes that promote fat accumulation and adipogenesis (the process of creating fat cells). “Participants with obesity were found to have higher urinary concentrations of 2,4-D and 2,5-D. Higher concentrations of these pesticides were associated with increased BMI and waist circumference,” the authors note. “As in children, the adult study showed a higher prevalence of obesity with higher urinary levels of 2,4-D and 2,5-D.” Additional studies find that carbendazim, thiophanate, benomyl, metalaxyl, propineb, and chlorpyrifos show a statistically significant association with obesity prevalence. (See Daily News here.)
A comprehensive research review published in Environment & Health analyzes existing research demonstrating the link between an increase in obesity and the proliferation of synthetic chemicals that “interfere with lipid metabolism.” The study documents over 50 obesogens with high-level human exposure rates, including per- and polyfluoroalkyl substances (PFASs), phthalates (PAEs), and polybrominated diphenyl ethers (PBDEs), that can lead to lipid metabolism disruption, including health impacts on the liver and insulin resistance, among other metabolic conditions such as diabetes, hypertension, cardiovascular disease, and dyslipidemia. (See Daily News here.)
A study in Journal of Agricultural and Food Chemistry finds permethrin, a commonly used synthetic pyrethroid insecticide, to be disruptive to the gut microbiome, altering microbiota and leading to increased formation of fat cells (adipogenesis) and metabolic disorders. With an aim to “comprehensively elucidate the effects of permethrin on gut microbiota, lipogenesis, and the associated molecular mechanisms,” the study explores the adverse effects of permethrin exposure in adult mice through multiple experiments. (See Daily News here.)
A study published in World Journal of Pediatrics finds an association between antibiotic and neonicotinoid (neonic) exposure and the onset of pediatric (childhood) type 1 diabetes (T1D) through effects on the gut microbiome. Individuals with type 1 diabetes are at higher risk of other autoimmune disorders, including thyroid and celiac disease. Over the past 20 years, neonicotinoids replaced four major chemical classes of insecticides in the global market (organophosphates, carbamates, phenyl-pyrazoles, and pyrethroids). (See Daily News here.) Another study published in Pesticide Biochemistry and Physiology finds organophosphate, organochlorine, and pyrethroid pesticides have links to insulin resistance associated with metabolic disorders like diabetes, obesity, chronic kidney disease (CKD), and hypertension. (See Daily News here.)
In addition, a meta-analysis published in Toxics finds an association between exposure to organophosphate pesticides (OPs) and respiratory diseases and diabetes mellitus (DM). Specifically, wheezing and asthma are the most common respiratory manifestations of organophosphate pesticide exposure, while fluctuation in weight and fat/glucose levels are the most common metabolically related manifestations. Concerning diabetes, the study suggests organophosphate pesticides could cause an excessive increase in body weight, impaired leptin (the protein that alerts the brain when there is enough fat stored, playing a role in body weight regulation) production, and fat and glucose dysregulation–all common precursors for diabetes, obesity, and other metabolic disorders. Additionally, the generation of reactive oxygen species (ROS) by OPs could also mediate insulin resistance. (See Daily News here.)
For additional coverage on scientific literature assessing the pesticide-diabetes connection, see here.
Call to Action
The best solution to the multiple problems associated with pesticide reliance is providing incentives and further support for farmers and land managers to transition to and maintain organically managed systems.
You can take action today by contacting your members of Congress to become a cosponsor of the Opportunities in Organic Act, which was reintroduced on January 29, 2026, by a cohort of 14 federal lawmakers led by U.S. Senator Peter Welch (D-VT) and U.S. Representative Jimmy Panetta (D-CA). Beyond Pesticides is one of many organizations endorsing this piece of legislation, per the press release by Senator Welch’s office.
Additionally, you can sign up for Action of the Week and Weekly News Update to stay notified on ways you can take action to expand public investments and programs that expand organic land management, in agricultural contexts and on public green spaces, parks, and playing fields, to move beyond a reliance on synthetic materials. See ManageSafeTM for addressing pest prevention and management for land and buildings.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Environment International
