14
Nov
Literature Review Finds Heightened Risks for Thyroid Cancer in Women with Pesticide Exposure
(Beyond Pesticides, November 14, 2025) A literature review in Ecotoxicology and Environmental Safety finds a sex-specific relationship between pesticide exposure and thyroid cancer, with heightened risks for women. “Thyroid cancer (TC) is one of the most common endocrine malignancies worldwide, yet the association between pesticide exposure and TC has not been systematically summarized,†the authors state. “This study aimed to elucidate the relationship between pesticide exposure and TC, focusing on insecticides, herbicides, and fungicides.â€
In the U.S., approximately 44,020 new cases and 2,290 deaths are estimated for 2025, according to the American Cancer Society, with thyroid cancer as the ninth most common cancer in women. (See research here.) TC ranks globally as the tenth most common cancer, representing a worldwide threat to both men and women. (See here.)
The current study considers scientific literature on thyroid cancer and pesticide exposure by pesticide type to extract data and statistically analyze the link between exposure and risk of TC. The results indicate a positive association between exposure to insecticides, herbicides, and fungicides and thyroid cancer, with the sex-based analysis revealing the risk of TC is higher in females.
Study Background and Importance
As the researchers write, thyroid cancer “is one of the most common endocrine malignancies worldwide… [and] accounts for 4% of all cancers worldwide, with 60% of cases occurring in Asia, indicating a severe disease burden in developing countries.†The occurrence of TC is linked to obesity, excessive iodine intake, exposure to ionizing radiation, and genetic factors, as well as environmental exposure to contaminants such as endocrine-disrupting chemicals (EDCs). (See research here.)
“The increased risk of thyroid diseases associated with pesticide exposure might be attributed to the similarity in chemical structure between them and the thyroid hormones,†the authors state. They continue: “This structural similarity allows pesticides to competitively bind to thyroid hormone transport proteins, disrupting thyroid hormone signaling and transport, leading to thyroid dysfunction. Such dysregulation reduces circulating thyroid hormone levels, potentially resulting in abnormal thyroid cell proliferation and tumor development.†(See studies here, here, and here.)
Methodology and Results
Through the literature review and subsequent data extraction and statistical analysis from 13 recent population-based epidemiological studies, spanning four countries, the researchers find associations between pesticide exposure by type and the incidence of thyroid cancer. As the authors note: “The results showed that exposure to three different types of pesticides—insecticides, herbicides, and fungicides—was positively associated with the risk of TC. Furthermore, gender differences revealed that women exposed to pesticides had a higher risk of developing TC than men, indicating that pesticide exposure is a risk factor for TC.â€
The meta-analysis of the 13 studies includes seven case-control studies, five cross-sectional studies, and one cohort study of 656,166 participants. The study methodology includes a range of questionnaires, interviews, and biomonitoring of pesticide exposure through serum and urine samples. In analyzing the studies by pesticide type, many overlap for multiple categories. Ten reference insecticides, six reference herbicides, and four reference fungicides, with an additional four studies also examining the association of TC and pesticide exposure from the sex perspective.
All of the studies included in the literature review show a statistically significant positive association between pesticide exposure by type to thyroid cancer, with the four sex-specific studies also showing that pesticide exposure, particularly for insecticides and fungicides, in females is positively associated with TC.
The authors conclude: “In summary, pesticide exposure may cause female estrogen secretion to be higher than that of men, resulting in excessive estrogen. Further binding to the Erα receptor [estrogen receptor alpha] further promotes the development of thyroid cancer, which leads to gender differences in TC after pesticide exposure… [T]he possible mechanisms by which pesticide exposure leads to TC include oxidative stress activation, abnormal expression of cancer-related genes, induced inflammatory responses, and disruption of the HPT axis secretion, leading to thyroid follicular hypertrophy and hyperplasia, which promote TC development.â€
Previous Research
A multitude of studies link pesticides and EDCs to thyroid dysfunction and cancer, as Beyond Pesticides has shared in previous Daily News coverage. Last year, a comprehensive literature review in Endocrines amassed hundreds of studies on EDCs that showcase adverse effects on growth, development, reproduction, and metabolism. The authors, a team of scientists and academics from Brazil, shed light on the link between EDC use and thyroid dysfunction, leading to increasingly prevalent illnesses and deadly diseases. (See Daily News here.)
For more information, see As Thyroid Cancer Cases Rise, Study Finds Pesticides Link, More Scientific Evidence that Endocrine-Disrupting Pesticides Disrupt Thyroid Function, and Exposure to Certain Pesticides Increase the Risk of Thyroid Cancer.
Within the current literature review, additional research is cited. This includes:
- Two studies (see here and here) link thyroid cancer and altered thyroid function to EDCs.
- Pesticide urinary metabolites are significantly associated with altered levels of thyroid-stimulating hormone (TSH), thyrotropin-releasing hormone (TRH), total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), and free thyroxine (FT4). (See study here.)
- “Studies have found that long-term exposure to low-dose pesticides can lead to thyroid diseases. For instance, a study in China found a significant negative correlation between pesticide metabolites and thyroid function markers.â€
- One study, in the U.S., demonstrates that “lifelong pesticide use among male pesticide applicators was associated with high TSH levels and subclinical hypothyroidism.â€
- “Another U.S. study found that several pesticides were linked to an increased risk of hypothyroidism and hyperthyroidism, with a strong association observed for fungicides.â€
- A study finds that there is an association between organochlorine pesticides and thyroid cancer.
- “Previous studies have indicated that insecticide exposure is associated with an increased risk of TC, such as a positive association between exposure to malathion [organophosphate insecticide] and atrazine [triazine herbicide] and TC incidence.â€
- A study of the organochlorine insecticide endosulfan in the U.S. finds a positive association to TC incidence.
- “It has been reported that the use of herbicides in central and southern Ukraine can affect the prevalence and incidence of TC and various types of goiter.†(See study here.)
- A study of dithiocarbamate fungicides finds that they are associated with a decrease in TSH levels.
- “In addition, a meta-analysis found that thyroid dysfunction was associated with an increased risk of thyroid cancer.â€
Solutions and Resources
Knowledge is power. In knowing that there is a wide body of scientific literature that connects pesticides to adverse health effects in humans, as well as in wildlife and in the environment, there is the ability to mitigate these impacts. In supporting the widespread transition to the holistic solution of organic land management, both health and the environment can be protected.
To learn more about thyroid cancer, and all other types of cancer that can be linked to pesticide exposure, visit the Pesticide-Induced Diseases database on cancer here. Additional Daily News coverage on thyroid dysfunction and disease can be found here.
Take action in your local community and through Action of the Week, a service through Beyond Pesticides for our supporters and network to share one concrete action that you can take each week to have your voice heard on governmental actions that are harmful to the environment and public and worker health, increase overall pesticide use, or undermine the advancement of organic, sustainable, and regenerative practices and policies.
Additional resources for adopting organic practices can be found in Beyond Pesticides’ resources hub including ManageSafe™ for Least Toxic Control of Pests in the Home and Garden, Non-Toxic Lawns and Landscapes, and Parks for a Sustainable Future.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Yang, X. et al. (2025) Association between pesticide exposure and thyroid cancer: A systematic review and meta-analysis, Ecotoxicology and Environmental Safety. Available at: https://www.sciencedirect.com/science/article/pii/S0147651325016276.
