31
Jan
Sleep Disorders in Farmers and Farmworkers Linked to Pesticide Exposure in Study Supporting Similar Findings
(Beyond Pesticides, January 31, 2025) A recent cross-sectional study in Heliyon highlights the link between sleep disorders in Thai farmers and pesticide exposure. The authors find pesticide exposure as an important risk factor for sleep disorders after surveying 27,334 farmers over the age of 20 who had work experience for at least five years.
The importance of sleep health is reflected both physically and mentally, as studies find “sleep deficiency increase[s] mortality and various health complications, including hypertension, obesity and type 2 diabetes, cardiovascular diseases, mood disorders, and neurodegenerative disorder.†Additional studies find that these issues are compounded when sleep health is affected by environmental factors such as pesticide exposure. (See previous Beyond Pesticides’ coverage here and here.)
The researchers report: “The study found a positive association of 19 individual pesticides (twelve insecticides, two herbicides, and five fungicides). Some associations demonstrated a dose-response pattern. Additionally, the study revealed that women are at a higher risk of sleep-related issues with pesticide exposure compared to males. These results not only substantiate existing literature but also unveil several new individual pesticides that may impact sleep health.â€
Focusing on study participants in Thailand, which is “characterized by heavy pesticide use and minimal protective measures, presents unique exposure circumstances that offer an opportunity to study the effects of pesticides,†the authors note. The farmers live in the three provinces in the north of Thailand that are the largest in terms of agricultural area, population, and pesticide use. Thai agriculture, according to the researchers, “accounts for about thirty percent of the workforce, [and] depends heavily on pesticides to control of weeds, insects, and fungi.†This places farmers and farmworkers with an elevated risk to the toxic effects of pesticides.
Within the study, consent forms and questionnaires were given to the randomly selected participants between October 2020 and February 2021. The questions were originally developed under the Agricultural Health Study from the U.S. and have been used in many cross-sectional studies. Historical pesticide exposure was assessed and the participants were placed into two groups for each pesticide of exposed and unexposed. 38 individual pesticides are included in the study, falling into several categories. The authors share that this encompasses “seven organochlorine pesticides, eight organophosphates, four carbamates, three other insecticides, seven herbicides, and nine fungicides. These pesticides were chosen based on findings from previous studies that indicated a connection to sleep health and their common usage in Thailand.â€
The reported pesticide exposure was compared to sleep disorder diagnoses, as confirmed with hospital records. “In this study, sleep disorder (F51) refers to a group of diseases including insomnia (F510), hypersomnia (F511), disorders of the sleep-wake cycle (F512), sleepwalking (F513), night terrors/sleep terrors (F514), nightmares (F515), and other sleep disorders (F518, F519).â€
The study results show that there is a significant association with sleep disorders for insecticide exposure between 116.1–442.5 days. A higher risk with fungicide and molluscicides exposure is noted with any use between 1.2–9030.0 days. The researchers report: “For individual pesticides, significant associations were observed in 19 out of 38 individual pesticides. There were twelve insecticides, including three organochlorine insecticides (chlorpyrifos, chlordane, dichlorodiphenyl trichloroethane [DDT]), five organophosphates (ethyl p-nitrophenyl phenylphosphorothioate [EPN], folidol, methamidophos, mevinphos, profenofos), three carbamates (carbaryl, carbofuran, methomyl), and imidacloprid.â€
Overall, the study shows that the female group displays higher associations with sleep disorders. Significant associations are also noted for “two herbicides (diuron and paraquat) and five fungicides (benomyl, Bordeaux mixture, carbendazim, copper sulphate, metalaxyl). The association for some chemicals, e.g., chlorpyrifos, DDT, endosulfan, carbosulfan were in a dose-response pattern.â€
The authors summarize these results, saying: “This study revealed a significant connection between historical pesticide use and sleep disorders. Remarkably, this association persisted even after adjusting for demographic variations and potential confounding from exposure to other pesticides.â€
Notable research on sleep health that the authors reference include:
- “A recent study in Almeria reported a higher risk of insomnia among farmers who did not wear gloves or masks when using pesticides.â€
- “Results from a well-designed follow up study among mother-adolescent pairs found sleep health of adolescents could be linked to pesticide exposure during pregnancy.†This study also “reported 3-PBA, a pyrethroid insecticide, to associate with insufficient sleep and trouble sleeping.â€
- “In an Agriculture Health Study in the US, a study found pesticide exposure to associate with dream-enacting behaviors or parasomnia. This finding was consistent with a previous US study which reported pesticides used at home could be associated with insufficient sleep and trouble sleeping among adults.†See studies here and here.
- “A study from Uganda reported acute pesticide exposure to increase risk of sleep problems, sleep inadequacy and snoring.†This study also finds the “fungicide mancozeb and herbicide glyphosate to increase risk of sleep problems” and a higher risk of sleep disorders among females.
- “In China, a study found greenhouse farmer with high cumulative pesticide exposure to have a short sleep duration, poor sleep quality, and difficulty sleeping.â€
- “Pesticides influence the acetylcholine, gamma-aminobutyric acid (GABA), and serotonin pathways, which are critical for sleep regulation. Disruption of these pathways may result in sleep disturbances by impairing the normal sleep-wake cycle.†See study here.
- “Exposure to endocrine-disrupting chemicals (EDCs), including specific herbicides and fungicides, may modify hormone levels (e.g., melatonin, cortisol) that play a direct role in regulating circadian rhythms and sleep patterns.”
- “Research indicates that pesticides may stimulate the generation of reactive oxygen species (ROS) and inflammatory cytokines, potentially affecting brain regions involved in sleep regulation, including the hypothalamus.â€
- “Previous studies also found a higher sleep problem among those exposed to organophosphate ester, carbamate insecticide as a group, and carbofuran.†(See studies here, here, here, and here.)
- “In animal studies, researchers found that paraquat increases oxidative stress, a condition that can decrease the length of the sleep-wake cycle and disrupt sleep consolidation.â€
Despite the Heliyon study not considering other potential risk factors for sleep disorders, such as body mass index (BMI), chronic disease, stress, or other psychological issues, this is a novel study that supports existing research linking pesticide exposure to sleep disorders. “A notable strength of this study lies in its collection of exposure information for various pesticides, coupled with the use of medically diagnosed diseases confirmed by ICD-10 [a medical classification list by the World Health Organization (WHO)], which is considered more accurate than relying on self-reported outcomes. The results provide valuable insights into the effects on sleep health in a developing country like Thailand, where pesticides are extensively used with minimal exposure prevention,†the researchers state.
The authors continue: “This study serves as a robust comparison group for results from studies conducted in other parts of the world. The impact of pesticides on sleep health deserves increased attention, considering that sleep deficits might be an underlying cause of various health problems and compromise the overall well-being of individuals. This significance is heightened by the widespread use of pesticides as chemicals.â€
In finding an association between occupational pesticide exposure and sleep disorders, this research contributes to the wide body of science highlighting the threats of pesticides to human health. In order to protect the health of humans and all organisms within the environment, organic land management practices are needed.
Organic agriculture provides a holistic solution that not only protects farmers and farmworkers, who are at disproportionate risk, but all organisms who are exposed to toxic chemicals through oral, dermal, and inhalation routes. To learn more about the benefits of organic, see here and here. For information about specific pesticides and alternatives, visit the Gateway on Pesticide Hazards and Safe Pest Management. Take action and have your voice heard by participating in the Action of the Week, where you can weigh in 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.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Juntarawijit, C. et al. (2025) Pesticide exposure and sleep disorder: A cross-sectional study among Thai farmers, Heliyon. Available at: https://www.cell.com/heliyon/fulltext/S2405-8440(24)17154-X.
