Just in time for the 41st annual Earth Day last Friday, the news media went wild reporting on a trio of highly flawed studies published in the journal Environmental Health Perspectives, a periodical now notorious for reporting on junk science research.
In the main study, Brenda Eskenazi and her colleagues from the University of California-Berkeley conducted a birth-cohort study of 400 children, most of whom came from Latino farm worker families in agricultural communities in California. Researchers followed the children’s health — beginning with the mothers during pregnancy, whose urine they analyzed for dialkyl phosphate (DAP), a metabolite of organophosphate (OP) pesticides. IQ tests were performed when the children reached the age of seven.
It was found that children in the highest quintile of maternal pesticide metabolite concentration had an average deficit of seven points on IQ tests compared to children in the lowest quintile. The authors did note, however, that the children’s urinary metabolite concentration was not consistently associated with cognitive scores.
The study findings went viral almost immediately, providing further ammunition for environmental activists’ campaigns against pesticide use — chemicals they claim lead to a slew of health maladies, now including a supposedly lower IQ. But ACSH’s Dr. Gilbert Ross analyzed the study and notes that the authors didn’t control for some very basic variables known to influence IQ, such as smoking, alcohol or drug use nor any paternal traits. “The study is flawed methodologically, and assumptions are made based on simple assertions with no scientific support. The authors acknowledge that the metabolites they measured did not necessarily come from the OP chemicals — they could have also come from ingestion of trace amounts of the metabolites themselves that had already formed elsewhere. In addition, missing data is imputed — some arbitrary value is just stuck in where none existed. It’s a sham.”
ACSH’s Dr. Elizabeth Whelan further points out that the study didn’t even postulate a potential mechanism of action of how pesticide exposure in utero might affect cognition later on. “Actually, there is no plausible biological hypothesis that could explain this association, but we do know that this journal has an environmental agenda that they stick to very closely.”
Since today marks the World Health Organization’s World Malaria Day, Dr. Ross emphasizes how beneficial pesticides are in terms of fighting global starvation as well as combating infectious diseases. “An overwhelming body of scientific evidence has clearly shown that OP pesticides have no adverse health effects, a finding also replicated by the EPA. Nevertheless, activists who persist in campaigning against pesticides fail to take into account the many benefits they provide, such as enhancing crop yields and the quality of the produce. Without these valuable chemicals, food would be significantly less healthful due to insect and other pest infestations that introduce disease microbes. But apparently, these chemophobes are happy to relegate others to starvation and potentially fatal insect diseases like malaria in order to serve their own anti-chemical, anti-technological political agendas.”