Exposure to lead can harm children's health, causing damage to the brain and nervous system and slowing down their development. Scientists have now found that lead exposure in the womb or in childhood increases the risk of criminal behavior in adults.

Lead poisoning occurs when an individual ingests, touches or breathes the toxic metal. According to the Centers for Disease Control and Prevention(CDC), there are no safe blood lead levels in children. Lead levels in the blood can impact learning, attention and development. It can also cause cardiac issues, kidney damage, immune system dysfunction and reproductive problems.

Although previous studies have shown an association between lead exposure and criminal behavior, the latest study was the first to conduct a systematic individual-level review.

The team evaluated 17 studies, which used different methods for measuring lead exposure such as blood, bone or tooth samples. They also examined the potential effects of the exposure at different stages of a person's life right from in-utero, to early childhood, adolescence and adulthood.

The review led to a range of findings, while some studies showed no statistical links between lead exposure and delinquent behavior, several others found that exposure during early childhood can be linked to later arrests, including drug-related incidents.

Based on the overall findings, researchers suggest that lead poisoning in the womb or early childhood poses a higher risk of criminal behavior later in adulthood.

"The evidence we found points in the direction of lead exposure being associated with biological effects in children that have long-term behavioral consequences," lead author Maria Jose Talayero Schettino said.

Researchers call for policy action to prevent lead exposure and more individual-level evidence to deepen the links they found from the review.

"Policy action to prevent lead exposure is of utmost importance as our research shows an excess risk for criminal behavior in adulthood exists when an individual is exposed to lead in utero or during childhood. Preventing lead exposure is crucial to safeguard public health and promote a safer society for all," the researchers said in a news release.