Cognitive decline is a growing concern for millions of older adults across the globe. If you’re over 60 or caring for someone who is, you’ve likely seen how small lapses in memory and attention could gradually worsen over time. More than 50 million people are currently living with Alzheimer’s disease, and that number is expected to triple by 2050.1
While aging is a major factor, researchers are uncovering other contributors that don’t come from within the body, but from ongoing exposure to environmental threats. One of those contributors is insecticide exposure. These chemicals are designed to disrupt the nervous systems of insects, yet traces linger in the air, food, water, soil, and dust people come into contact with every day.
Acute poisoning from insecticides is already known to cause neurological harm. But the greater concern now lies with long-term, low-dose exposure, especially among older adults whose brains are already vulnerable. A recent study published in Frontiers in Public Health2 adds to mounting evidence that repeated exposure to insecticides steadily impairs memory, learning, and mental sharpness over time.
Insecticide Exposure and Cognitive Performance in Older Adults
In the featured study, researchers analyzed 1,544 individuals aged 60 and up, drawing data from the U.S. National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2014. The aim was to investigate whether recent contact with insecticides had any relationship to measurable signs of cognitive decline.3
• Cognitive testing reflected real-world mental function — Participants were evaluated using standard memory and thinking tests that reflect real-world skills, including word recall, delayed memory, verbal fluency, and processing speed. Those who reported insecticide use inside the home within the past week scored lower, on average, particularly on tests related to memory.
• Memory tests revealed the strongest associations — The clearest signal appeared in word learning and recall, which correspond to daily tasks like remembering names, conversations, or appointments. A key finding involved trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA), a urinary metabolite of pyrethroid insecticides, which showed a significant association with impaired memory.
• Pyrethroids are the most widely used household insecticides — Pyrethroids are found in many over-the-counter bug sprays, foggers, and pest control products marketed for home use. They are used to kill mosquitoes, cockroaches, ants, fleas, and other household pests, and are also common in lawn treatments, pet shampoos, and lice kits.4
Active ingredients such as permethrin, deltamethrin, cypermethrin, and allethrin all belong to the pyrethroid class of insecticides.5 Because pyrethroids are applied indoors, outdoors, and on the body, exposure occurs through inhalation, skin contact, and ingestion.
• Cross-sectional design limits causal conclusions — Because the study measured exposure and cognitive status at the same time, it can’t confirm directionality. Early memory impairment might affect how people report or use insecticides. The study also didn’t capture occupational exposure, long-term rural residence, or genetic risk factors.
• Despite these limitations, the biological mechanisms support the findings — Insecticides are designed to interfere with the nervous systems of insects, but they also affect human biology, especially the brain. Many act by inhibiting an enzyme called acetylcholinesterase, which is responsible for breaking down acetylcholine, a neurotransmitter essential for attention, learning, memory, and muscle control.
When acetylcholinesterase is blocked, acetylcholine accumulates in the synapses between nerve cells, leading to continuous stimulation of neurons. This overstimulation disrupts normal brain signaling, impairs communication between neurons, and ultimately damages or kills nerve cells.
In animal studies, insecticide exposure has been shown to cause oxidative stress, inflammation, mitochondrial damage, and structural breakdown in brain areas vital for memory and cognition. These effects have been observed even at low doses.
While the study can’t prove causation, it adds to growing evidence that regular exposure to neurotoxic chemicals gradually erodes cognitive resilience. The link between trans-DCCA and memory performance suggests that even routine household products have neurological consequences over time.
Living Near Sprayed Fields Linked to Cognitive Decline
A related investigation from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD), a population-based study in Greece, evaluated 1,397 adults over the age of 64 who did not have dementia. The goal was to assess how different forms of pesticide exposure influenced cognitive performance. Researchers used a detailed battery of neuropsychological tests to measure multiple aspects of memory and thinking.
• Proximity to pesticide use linked to worse cognitive scores — The study participants were grouped based on whether they lived in areas where pesticide spraying occurred, used pesticides in home gardens, or had occupational exposure through farm work or pesticide application.
Among them, those living closest to active agricultural spraying sites performed worse on neuropsychological tests measuring attention, executive function, language, and visuospatial skills. These cognitive domains are essential for navigating daily tasks like decision-making, processing language, and interpreting visual information.
• Effects remained even after excluding early cognitive impairment — This strengthens the finding by showing that the effect was not simply due to early signs of dementia. The negative associations persisted in adjusted models that accounted for a range of demographic and health-related variables. These adjustments included age, sex, education, and vascular risk factors, which are known to influence cognition.
• Findings align with U.S. NHANES data and broaden its scope — Like the NHANES study, this research shows lower cognitive scores in individuals with recent or ongoing pesticide exposure. But HELIAD adds an environmental angle, showing that simply living near sprayed fields, even without personal use, carries measurable cognitive risks.
• Results are supported by global epidemiological evidence — The authors cite similar findings from population studies in Canada and Chile, which also reported associations between pesticide exposure and increased risk of cognitive decline or dementia.
Some of these earlier studies focused on occupational exposure among agricultural workers, while others highlighted community-level environmental contact. The HELIAD findings add support to this literature by documenting significant associations in a general older adult population not selected based on occupational background.
These results echo growing concerns about how everyday chemical exposures affect brain function as you age. To learn more about how proximity to pesticide-treated areas influences your risk, read “Living Near a Golf Course Puts Your Brain Health at Risk.”
A Public Resource Linking Pesticides to Chronic Disease
For those seeking a broader picture of how pesticides harm long-term health, the Pesticide-Induced Diseases Database is a valuable tool. Maintained by the nonprofit Beyond Pesticides, this searchable, peer-reviewed resource compiles hundreds of studies documenting links between pesticide exposure and serious chronic conditions across multiple body systems.6
• Evidence spans multiple disease categories — The database includes research-backed links to central nervous system tumors, Parkinson’s disease, amyotrophic lateral sclerosis (ALS), multiple sclerosis, stroke, childhood leukemia, and migraines. It also covers respiratory disorders like asthma and chronic bronchitis, as well as thyroid dysfunction, birth defects, endometriosis, infertility, and other forms of reproductive damage.
Additional entries document associations with diabetes, endocrine disruption, immune dysfunction, learning and developmental delays, and systemic hormonal imbalances. Moreover, it tracks categories such as “body burden” and emerging concerns related to genetically engineered pesticide traits.
• Risk isn’t limited to farmworkers — In many of the referenced studies, increased risk is observed not only among occupational users but also in those exposed through residential proximity, agricultural drift, food residues, and contaminated water sources. These exposures often accumulate over time and interact with other vulnerabilities, particularly in vulnerable groups, such as pregnant women, children, and older adults.
The range of evidence gathered in the database strengthens the case that pesticides are not just short-term toxicants, but long-term drivers of chronic disease. It expands on cognitive research by showing how neurological damage fits into a broader pattern of long-term, system-wide harm.
5 Practical Steps to Reduce Pesticide Exposure
Pesticides are difficult to avoid. They’re present in the air, water, and food supply, and are used in residential, agricultural, and public settings. Whether you live near farms, suburban lawns, or city green spaces, your daily environment likely contains some level of exposure. However, that doesn’t mean you’re powerless. Here are clear, actionable steps you can take to reduce your pesticide burden and protect your long-term cognitive health.
1. Sweat regularly to support detoxification — Activities that make you sweat, like interval walking training (IWT), cycling, or spending time in a sauna, are among the most effective ways to help your body eliminate stored pesticides and heavy metals.
On top of that, regular physical activity improves nearly every aspect of health, from metabolism to brain function. There’s no downside to moving your body, and best of all, it’s free, simple, and available whenever you’re ready.
2. Filter your drinking water — Tap water may contain trace amounts of pesticides from agricultural runoff or groundwater contamination. Using a high-quality water filter designed to remove pesticides, fluoride, and heavy metals adds a layer of protection. Choose a filter that fits your household needs and change cartridges regularly to maintain effectiveness.
Ideally, water needs to be filtered at both the main supply line entering your home (point of entry) and again at key locations where it’s consumed or used, such as the kitchen sink and showers (points of use). This dual approach ensures broader protection against a range of contaminants.
3. Improve indoor air quality — Airborne pesticides drift into your home and settle on surfaces. Using air purifiers with HEPA filters and cleaning frequently with nontoxic methods helps reduce indoor buildup. Keeping windows closed during nearby spraying or peak agricultural activity also helps limit intake through inhalation.
4. Choose organic food when possible — Choosing organic fruits and vegetables is one of the most effective ways to lower your body’s chemical load and support long-term detoxification. Many conventional crops carry residues from the same chemical classes used on fields and landscaped neighborhoods, adding to your total exposure.
To get the most benefit, it helps to understand what organic labels actually mean. Knowing how to read and verify them ensures you’re getting truly clean food. For a deeper breakdown, read “New ‘Dirty Dozen’ List Warns About Rising Pesticide Residue in Common Produce.”
5. Advocate for safer practices in your community — Taking action at the local level makes a real difference. Reach out to city or county officials and push for stronger regulations on pesticide use. Policies modeled after stricter international standards, like those in parts of Europe, lead to safer communities and lower exposure for you and your family.
Frequently Asked Questions (FAQs) About Pesticide Exposure
Q: Can insecticides really affect my memory or mental sharpness?
A: Yes, repeated low-level exposure to insecticides has been linked to measurable declines in memory and thinking skills. Studies have found that older adults exposed to insecticides score lower on memory tests. These effects often appear in everyday tasks like recalling words, concentrating, or staying organized.
Q: What kinds of insecticides are linked to cognitive decline?
A: The strongest links have been found with pyrethroids, a class of insecticides used in many household products like bug sprays, pet shampoos, and lawn treatments. A urinary biomarker called trans-DCCA, which indicates pyrethroid exposure, has been associated with lower memory scores in older adults.
Q: If I don’t work with pesticides, am I still at risk?
A: Yes. You don’t have to be a farmworker or landscaper to be affected. Research shows that people who live near areas where insecticides are sprayed, such as agricultural fields or manicured residential neighborhoods, have similar or even greater risks. Environmental drift, contaminated water, and indoor residues all contribute to long-term exposure, even if you’ve never handled these chemicals directly.
Q: What other diseases are linked to pesticide exposure?
A: Pesticide exposure has been associated with a wide range of chronic health problems. According to Beyond Pesticides’ Pesticide-Induced Diseases Database, these include central nervous system tumors, Parkinson’s disease, ALS, stroke, thyroid dysfunction, infertility, diabetes, and childhood leukemia. There’s also research linking pesticide contact to asthma, birth defects, immune system disorders, and developmental delays.
Q: What can I do to lower my exposure to pesticides?
A: You can reduce your exposure by using HEPA-filter air purifiers, choosing organic food whenever possible, filtering your tap water, avoiding pesticide use at home, and staying indoors during spraying periods. Regular exercise and sauna use also helps your body eliminate stored toxins. At the community level, you can advocate for stricter pesticide regulations to protect yourself and others from chronic chemical exposure.