A systematic review of 25 studies conducted over almost 50 years indicated a strong association between pesticides that are commonly found in food and lower sperm concentrations.
A team of researchers at the George Mason University College of Public Health as well as Northeastern University in the US have published research indicating a strong link between exposure to common pesticides and lower sperm counts.
“Understanding how insecticides affect sperm concentration in humans is critical given their ubiquity in the environment and documented reproductive hazards,” Lauren Ellis, a doctoral student at Northeastern University involved in the research project, said.
“Insecticides are a concern for public health and all men, who are exposed primarily through the consumption of contaminated food and water,” she added.
The research, which was published today in the peer-reviewed journal, Environmental Health Perspectives, involved a systematic review of 25 studies on the subject conducted over 50 years.
Specifically, those studies looked at the impacts of exposure to two widely used insecticide classes, organophosphates and N-methyl carbamates with the research team finding consistent associations with lower sperm concentration across the studies.
According to the National Library of Medicine in the US, organophosphorus pesticides (OPs) are one of the most common classes of chemicals used for the control of insects on vegetables because of their high efficacy and broad spectrum of activity.
Residue of OPs are likely to be found in common foodstuffs like lettuce and cabbage.
N-methyl carbamates are equally prevalent across a spectrum of field, fruit, and vegetable crops, according to the US Centres for Disease Control and Prevention (CDC).
Sperm concentration, or sperm density refers to the number of sperm per millilitre of semen and has an important influence on fertility.
Sperm count refers to the total number of sperm in a sample or ejaculate, which can be calculated by multiplying sperm concentration by semen volume.
However, sperm concentration “is an important measure of sperm quality for comparing men across studies because it adjusts for variability in semen volume,” Melissa J Perry, the dean of the George Mason University College of Public Health, specified in an interview with CNN.
“There is plenty of evidence to advocate for reducing exposure to insecticides, especially among men who are intending to plan their family and father children,” Perry added in a separate video presenting the findings.
She also acknowledged that the researchers were "surprised" by the findings and encouraged policymakers to recognise insecticide exposure as a public health issue.
In the past 50 years, sperm counts have halved across the world.
A study from the Hagai Levine of Hebrew University of Jerusalem’s Hadassah Braun School of Public Health, published last year also indicated that the trend has been accelerating since the turn of the century.