“Understanding how insecticides affect sperm concentration in humans is critical given their ubiquity in the environment and documented reproductive hazards. Insecticides are a concern for public health and all men, who are exposed primarily through the consumption of contaminated food and water,” says Ellis.

The team reviewed decades of human evidence regarding the health impacts of exposure to two widely used insecticide classes, organophosphates and N-methyl carbamates, and found consistent associations with lower sperm concentration, which warrants concern, particularly in light ofobserved downward trends in semen quality demonstrated by other studies.

“This review is the most comprehensive evidence sizing up more than 25 years of research on male fertility and reproductive health. The evidence available has reached a point that we must take regulatory action to reduce insecticide exposure,” says Dr. Perry, the senior author on the paper.

The research team systematically reviewed 25 human studies of occupational and environmental insecticide exposure conducted over the course of25 years.To the reviewers’ knowledge, this is the most comprehensive systematic review on this topic to date, and the first to use these methods to quantitatively synthesize decades of epidemiological literature.

“Adult Organophosphate and Carbamate Insecticide Exposure and Sperm Concentration: A Systematic Review and Meta-Analysis of the Epidemiological Evidence” was published online in Environmental Health Perspectives in November 2023 (DOI is 10.1289/EHP12678). Karen Molina, C. Rebecca Robbins, and Marlaina Freisthler from George Washington University; Daria Sgargi from the Cesare Maltoni Cancer Research Center, Ramazzini Institute; and Daniele Mandrioli from the University of Bologna are additional authors on the paper.

Most of the research was conducted while Perry and Ellis were at George Washington University. There was no outside funding for this research.