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A study published in the Journal of Endocrinological Investigation finds exposure to the insecticide chlorpyrifos and other organophosphates (OPs) has a positive association with the development of erectile dysfunction (ED).

Erectile dysfunction, also known as impotence, is the difficulty of getting or keeping an erection. Despite occurring in males later in life (between 40 and 70 years), recent studies highlight this issue emerging among adolescents, highlighting possible hormone imbalances not associated with age.

Scientists and health officials already associate pesticide exposure with a decrease in male fertility, including reduced sperm count, quality and abnormal sperm development.

Exposure to many pesticides also profoundly impacts the endocrine (hormone) system, including reproductive health.

Globally, ED is increasing, with over 300 million men expected to have ED by 2025.

Although age and comorbid conditions (e.g., obesity, diabetes and hypertension) play a role in ED prognosis, studies, including this one, suggest environmental contaminant exposure can also explain the increasing trend in ED.

The study notes:

“Future studies are warranted to corroborate these findings, determine clinical significance, and to investigate biological mechanisms underlying these associations.”

Using data from the National Health and Nutrition Examination Survey, researchers investigated urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of the most common OP insecticide chlorpyrifos.

Researchers compared urinary levels to patients who experienced ED, responding to a questionnaire indicating if the individuals were “sometimes able” or “never able” to achieve an erection.

A linear and logistic regression compared sociodemographic variables between chlorpyrifos exposure to identify risk factors for exposure and ED and analyze the relationship between TCPy and ED.

Of the 671 male patients in the study, about 37% have ED, with smoking, diabetes, aging, identifying as Mexican–American and physical inactivity having the highest association with ED prevalence.

However, the study highlights the increased odds of ED among individuals exposed to chlorpyrifos, with the risk of ED rising with increased exposure to the chemical.

The presence of pesticides in the body has implications for human health, especially during vulnerable life stages, such as childhood, puberty, pregnancy and old age.

For instance, prepubescent exposure to pesticides can impair male reproduction through the interruption of testicular homeostasis and the development of reproductive Leydig cells and can have multigenerational effects.

Furthermore, pesticide pollutants in groundwater, soils, household products and chemical manufacturing by-products are on a growing list of culprits causing developmental abnormalities such as impaired sperm quality and impotence.

Reproductive health can be compromised if males are exposed at various times in life, spanning from in utero up to adulthood. Erectile dysfunction is reported in one-third of the U.S. male population and has links to chemicals in the environment.

Vinclozolin, a fungicide commonly used in agriculture, can contaminate food and water supplies, and laboratory tests found that some male offspring of animals exposed to vinclozolin during pregnancy displayed a complete lack of interest in females.

This study is one of the first to investigate the relationship between specific OPs and ED, focusing mainly on the biomarker for chlorpyrifos exposure (TCPy), rather than just general OP metabolite dialkylphosphates.

The study also highlights the mechanisms involved in developing ED, including inhibiting acetylcholinesterase, the enzyme responsible for degrading acetylcholine at synapses and deregulating cholinergic pathways.

Considering the cholinergic system is significantly involved in erectile function, the study suggests that dysregulation by OPs has a relationship with ED development.

Oxidative stress can also play a role in cholinergic toxicity and is likely relevant to general population exposure levels. Additionally, OPs are known to impact smooth muscle pathways throughout the body, including the penis.

Another mechanism potentially involved in ED development is endocrine disruption, as many OPs are endocrine disruptors, binding directly to hormone receptors, like androgen, and decreasing androgenic properties from the adrenal glands and testes.

Since androgen signaling can influence normal erections, OPs can potentially mitigate signaling through a lack of testosterone production.

Lastly, the study suggests the obesogenic properties of OPs can play a role in ED development. Independently, obesity is a risk factor for ED.

However, OPs can accumulate within fatty (adipose) tissue. Thus, individuals with higher levels of fat stores have an increased risk of ED as concentrations of OP can be higher and remain in the body for longer.

Despite the findings of this study and many other related to health effects from chlorpyrifos exposure, the 9th Circuit U.S. Court of Appeals vacated the U.S. Environmental Protection Agency’s (EPA’s) 2021 decision to cancel all food tolerances for chlorpyrifos concluding that:

“EPA is unable to conclude that the risk from aggregate exposure from the use of chlorpyrifos meets the safety standard of the Federal Food, Drug, and Cosmetic Act (FFDCA). Accordingly, EPA is revoking all tolerances for chlorpyrifos.”

The prevalence of ED has been increasing over the decades, with men experiencing ED 10 to 15 years earlier than expected. Wildlife, laboratory, and epidemiologic studies show exposure to low-level environmental contaminants, such as pesticides and other chemicals, subtly undermines the ability to reproduce.

Furthermore, studies regarding endocrine disruption reveal mechanisms that show how specific chemical toxicants can alter fertility.

Therefore, advocates urge that policies strengthen pesticide regulations and increase research on the long-term impacts of pesticide exposure. Beyond Pesticides tracks the most recent studies related to pesticide exposure through our Pesticide Induced Diseases Database (PIDD).

This database supports the clear need for strategic action to shift away from pesticide dependency. For more information on the multiple harms of pesticide exposure, see PIDD pages on Sexual and Reproductive Dysfunction, Birth/Fetal Effects, Endocrine Disruption, Cancer, Body Burdens and other diseases.

The ubiquity of pesticides in the environment and food supply is concerning, as current measures restricting pesticide use and exposure do not adequately detect and assess total environmental chemical contaminants.

For instance, 90% of Americans have at least one pesticide biomarker (including parent compound and breakdown products) in their body.

However, one way to reduce human and environmental contamination from pesticides is to buy, grow and support organic. Numerous studies find that levels of pesticides in urine significantly drop when switching to an all-organic diet.

Furthermore, given the wide availability of non-pesticidal alternative strategies, families, from rural to urban, can apply these methods to promote a safe and healthy environment, especially among chemically vulnerable individuals or those with health conditions.

For more information on how organic is the right choice for consumers and the farmworkers that grow our food, see the Beyond Pesticides webpage, Health Benefits of Organic Agriculture.

Originally published Beyond Pesticides.