INMA: “INMA Study Investigates Link Between Pesticide Exposure and Puberty Development in Children”
A recent study conducted as part of the INMA cohort has delved into the potential link between pesticide exposure and the development of puberty in children.
Pesticides are chemical substances or mixtures designed to control, prevent, repel, or destroy pests that can adversely impact agricultural productivity. These pests can range from insects and weeds to fungi, rodents, and disease-causing pathogens. Pesticides come in various forms such as sprays, powders, liquids, granules, or baits and are applied to crops, soil, water, or structures. Although the use of pesticides offers benefits, including protecting crops, improving agricultural yields, and preventing the spread of diseases carried by pests, their improper use or over-reliance can have adverse effects on human health. Pesticides are primarily consumed through conventionally grown fruits and vegetables, making diet the main exposure route for the general population.
These chemicals have raised concerns due to their potential to disrupt the normal functioning of hormones in the human body, and are widely classified as endocrine-disrupting chemicals (EDCs). Experimental evidence suggests that these EDCs may have adverse effects on puberty timing in children. The timing of puberty, in turn, can have various health implications for individuals – it might affect personal and emotional well-being, growth and bone health, reproductive health, and associate with other health risks in the future, such as obesity, type 2 diabetes, cardiovascular risk, or even breast cancer.
However, existing studies present conflicting findings on the relationship between pesticide exposure and puberty. Some studies indicate that certain pesticides are associated with early puberty in girls, while others report delayed sexual development in both boys and girls. These effects have been observed across various countries, including the UK, Belgium, China, and Denmark. Given Spain’s significant consumption of pesticides within the European Union, the researchers aimed to investigate the potential association between exposure to pesticides and puberty development in children from the INMA cohort.
The study examined the levels of pesticide metabolites in urine samples collected from children aged 7 to 11 years and assessed their pubertal development using Tanner stages and the Pubertal Development Scale. Pesticide metabolites measured were: a metabolite of chlorpyrifos; a metabolite of diazinon; a non-specific metabolite of organophosphates; a metabolite of pyrethroids; and a metabolite of fungicides. These pesticides are of great interest because they are commonly used in food production and non-agricultural settings.
The findings revealed that higher concentrations of specific pesticide metabolites, such as the metabolites of organophosphates and of fungicides, were associated with an increased likelihood of overall puberty development in girls. The metabolite of fungicides was also linked to a higher probability of breast development, particularly in girls with underweight or normal weight. In boys, the urinary presence of the metabolites of chlorpyrifos and of pyrethroids was associated with a greater likelihood of genital development. Interestingly, the association for the pyrethroids metabolite was observed primarily in boys with overweight or obesity. Furthermore, the study found that higher urinary concentrations of the metabolite of fungicides were associated with an increased likelihood of genital development in boys who had underweight or normal weight. On the other hand, higher levels of organophosphates were linked to reduced odds of puberty in boys with overweight or obesity
Overall, this INMA study suggests that exposure to certain pesticides during childhood may be associated to pubertal outcomes, including earlier breast development in girls and earlier genital development in boys. Interestingly, these associations might be affected by childhood obesity status. The study highlights the potential interference of these contemporary pesticides with the hypothalamic-pituitary-gonadal (HPG) axis, which regulates pubertal timing. These findings shed light on the potential health impacts of pesticide exposure during critical stages of development and emphasize the need for further investigation into the effects of these chemicals on pubertal development.
Reference: Castiello F, Suárez B, Beneito A, Lopez-Espinosa MJ, Santa-Marina L, Lertxundi A, Tardón A, Riaño-Galán I, Casas M, Vrijheid M, Olea N, Fernández MF, Freire C. Childhood exposure to non-persistent pesticides and pubertal development in Spanish girls and boys: Evidence from the INMA (Environment and Childhood) cohort. Environ Pollut. 2023 Jan 1;316(Pt 2):120571.
Link to scientific article: https://doi.org/10.1016/j.envpol.2022.120571