Insecticide exposure linked to lower sperm count in adult males, Northeastern researcher finds

Headshot of Cesareo Contreras
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A red tractor is seen from above, spreading insecticides over a green field.
A farmer spreads pesticide on a field in Centreville, Maryland. Photo by JIM WATSON/AFP via Getty Images

Exposure to commonly used insecticides can be linked to a reduction in sperm concentration in adult men, according to a Northeastern University researcher.

The research, published in Environmental Health Perspectives, found that men who are highly exposed to insecticides such as organophosphates (OPs) and N-methyl carbamates (NMCs)  have lower sperm concentration than those less exposed. 

“There’s been plenty of animal and cell-based studies on these insecticides that have shown reproductive hazards,” says Lauren Ellis, the lead author of the study and a doctoral student at Northeastern studying population health and environmental epidemiology. “So it’s really important to understand the impact of these chemicals on human health, which is where epidemiology comes in, studying the impact not just on animals, but on humans.”

While there has been much research on the topic there have been limited meta-analyses of human evidence, Ellis says. For the study, the researchers sifted through three scientific databases (PubMed, Scopus and Web of Science) and two governmental databases (NIOSHTIC-2 and Science.gov) and analyzed over 25 studies conducted over 50 years that examined the relationship between OP and/or NMC insecticide exposure and sperm concentration in adult men 18 and older.

Headshot of Lauren Ellis.
Northeastern doctoral student and environmental health researcher Lauren Ellis recently found that there is a strong association between insecticide exposure and lower sperm concentration in adult men globally. Photo by Alyssa Stone/Northeastern University

“There is a strong and robust association across the body of evidence demonstrating that those more highly exposed to insecticides have lower sperm concentrations,” Ellis says.  

Organophosphates are often used in garden and agriculture pest control products, along with flea and tick collars and treatments for head lice. N-methyl carbamates are also found in similar products. It’s well understood that pesticides can cause harm to humans. In fact, some are carcinogenic, while others may affect hormones and the endocrine system. 

People can be exposed to insecticides in a variety of ways, including through skin contact, breathing or eating and drinking them, according to the Centers for Disease Control and Prevention. 

Ellis says she hopes the study will help shed light on how to reduce the use of these types of products. 

“We really hope that the study will spur solutions in both the regulatory setting and the engineering setting to reduce exposure,” Ellis says. 

Ellis is quick to clarify that there were limits to the study. 

“Because many of these studies were cross-sectional, meaning they measured exposure and outcome at the same time, we weren’t able to make a firm conclusion to say, ‘after being exposed to pesticides your sperm concentration is reduced’,” she says. “However, we did find a consistent and strong association between men who had higher exposures and also had lower sperm concentration.”      

Cesareo Contreras is a Northeastern Global News reporter. Email him at c.contreras@northeastern.edu. Follow him on X/Twitter @cesareo_r and Threads @cesareor.

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