Developmental Delays

Disorders in childhood development vary in scope and underlying causes. A supportive home environment with adequate nutrition can prevent some disorders and is important in all geographies and settings to improve children’s quality of life. Exposures to specific chemicals, such as lead, have been linked to developmental delays. But pesticide exposure is not an established cause of problems during childhood development.

Definitions

Childhood development encompasses many aspects of growth from birth to adolescence. Health professionals use multiple tools and tests to measure mental and/or physical performance. Deficits can lead to the diagnosis of a wide spectrum of disorders such as autism, attention deficit hyperactivity disorder (ADHD), decreased intelligence and learning disabilities.

Pesticide exposure is not an established cause of problems during childhood development.

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The term “pesticides” is also a widespread term referring to a group of products – both synthetic and natural or biological – which, by definition, are harmful to a plant, insect, fungus or rodent. Today, for a pesticide to be legally sold and used across the globe, specific and stringent tests are required to evaluate the potential for it to cause developmental delays.

Childhood Development in Society

It goes without saying that childhood development is a global public health priority. Delays in a child’s ability to learn, communicate and socialize can prevent the child from reaching his or her full potential. The causes for many disorders, such as ADHD, are largely unknown. Multiple factors that range from genetics to exposure to lead and other chemicals are being explored.  Some disorders are the result of maternal infections, such as with rubella virus, or excessive use of drugs and alcohol during pregnancy. Other conditions may develop in childhood because of nutritional deficiencies or inadequate caregiving. The World Health Organization estimates that as many as 43 percent of children in low- to middle-income countries may be vulnerable to developmental delays because of factors related to poverty.

Classification

Regulatory bodies such as the European Food Safety Authority (EFSA), United States Environmental Protection Agency, and Australian Pesticides and Veterinary Medicines Authority evaluate specific pesticides in animals for potential developmental neurotoxicity in humans. But not all human disorders and behaviors can be tested in laboratory animals. Nevertheless, required tests provide insight into the biological processes of pesticides. They are conducted at levels of exposure that farm workers or people at large, including pregnant women, would never ordinarily experience. Personal exposures to pesticide handlers can be further reduced by wearing protective clothing and following label directions.

For pesticides, repeated studies have not confirmed the initial associations, such as with IQ.

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Evidence in Human Studies

To study childhood health, researchers look among groups of children (population or epidemiological studies) that have the same condition, such as autism, and compare their experiences to children without the condition. Some of these studies also try to determine if a specific pesticide is used more frequently in the group with the medical condition. These statistical exercises may link a diagnosis with many different factors, but for pesticides, repeated studies have not confirmed the initial associations, such as with IQ.¹

A review by the EFSA of pesticides and health effects recommends “cautious interpretation” of epidemiological studies. For example, of studies on ADHD, it concluded “there is no evidence to suggest association between pesticide exposure and ADHD.”²

In general, pesticides are not an established cause of developmental delays or other childhood disorders. Studies continue to be conducted in humans, animals (“in vivo”) and cellular systems (“in vitro”) to better understand factors related to childhood development.