A 22-year study finds an association between childhood exposure to pesticides and early puberty
Pesticides and fungicides ingested primarily through fruit and vegetable consumption were associated with a higher likelihood of earlier initiation of development, breast in girls and genital in boys.
The research has been carried out by scientists from the University of Granada, the Biosanitary Research Institute (ibs.GRANADA) and CIBERESP (ISCIII)
A study carried out in a Spanish child population, with follow-up from pregnancy to adolescence (an average of 22 years), finds an association between the exposure of children to pesticides and fungicides and an advance in puberty.
The work, published in the scientific journal Environmental Pollution, and whose results have been announced today at a press conference, has been carried out by researchers from the University of Granada (UGR), the Biosanitary Research Institute (ibs.GRANADA) and CIBERESP (ISCIII).
This is new research on human exposure to hormonal contaminants and effects on maternal and child health from the multidisciplinary group Childhood and Environment (INMA), in which different research centers from Asturias, Guipúzcoa, Sabadell, Menorca, Valencia and Granada participate. .
The CIBERESP researcher and the research group A15-Basic and Clinical Oncology from the ibs.GRANADA, Carmen Freire, responsible for this publication, points out that very few studies to date have investigated the relationship between exposure to currently used pesticides and the age at which puberty appears in girls and boys, despite the fact that the advancement of Pubertal development is a fact frequently observed in the pediatric clinic, especially in girls, and whose causes are not well understood.
In this study, the association between various urinary metabolites of non-persistent pesticides and pubertal development in boys and girls from urban and rural areas of Spain was evaluated, considering obesity, as it is a risk factor in the advancement of development. It must be remembered that childhood obesity is a serious public health problem, which is why Spain has established a specific Strategic Plan (2023-2030) to combat it.
Spain is the largest consumer of pesticides in the European Union (EU), using 77.700 tons of pesticides in 2020, including 34.000 tons of fungicides, the largest group. Pesticides are used in agricultural production, as well as in urban and domestic settings. The main route of exposure in the general population is through the diet, especially through the consumption of conventionally produced fruits and vegetables.
Endocrine disruptors
Once in the human body, these pesticides are rapidly metabolized and excreted in the urine. Experimental studies suggest that some non-persistent pesticides may act like endocrine-disrupting chemicals, known as endocrine disruptors. Increased exposure to these endocrine disruptors in recent decades may be one of the factors responsible for the trend toward earlier onset of puberty in girls, and possibly boys as well.
In this work, the researchers analyzed urine samples from 606 girls and 933 boys, aged between 7 and 11, who participated in the INMA study between 2010-2016.
The analysis measured the concentration of four metabolites of organophosphate insecticides, including chlorpyrifos, diazinon and pyrethroids, widely used in the control of agricultural pests, as well as dithiocarbamate fungicides, such as mancozeb.
The results obtained show that, in girls, higher urinary concentrations of fungicide and insecticide residues were associated with a greater probability of presenting signs of having started puberty, especially mammary development. These associations were more evident in girls with normal weight.
In boys, exposure to the insecticide chlorpyrifos and pyrethroids was associated with a higher likelihood of genital development. As in girls, fungicides were associated with a higher chance of genital development in boys of normal weight. Furthermore, the association with pyrethroids was observed, interestingly, only in overweight/obese men.
In short, points out Carmen Freire, “the results suggest an association of childhood exposure to fungicides and certain insecticides with earlier puberty in girls and boys. These results are very worrying since precocious puberty has been linked to different disorders in childhood and adolescence, with late consequences for their health”.
Nicolas Olea, researcher in charge of the group A15-Basic and Clinical Oncology del ibsGRANADA, professor of the Department of Radiology and Physical Medicine of the UGR and another of the signatories of the work, highlights that it is striking that more than 60% of girls and boys have organophosphate pesticides in their urine, with diazinon leading the list, followed of fungicides, in more than half of the population, and then chlorpyrifos and pyrethroids, detected in about 40% of children. "This is something that should never have happened," he said.
Both the organophosphate insecticide chlorpyrifos and the dithiocarbamate fungicide mancozeb have been banned in Europe very recently (2020 and 2021, respectively) by the European Food Safety Authority (EFSA), although for many years they have contributed to placing Spain in the top positions of use of pesticides.
Unfortunately, other very similar pesticides are taking its place. In addition, adds Olea, "it is striking that, once they are banned due to their toxicity, nothing is done to remedy the damage caused by those who put them on the market."