Lithium in Drinking Water May Increase Autism Risks: Study

Pregnant women exposed to the highest levels of lithium in drinking water had a nearly 50% increased chance of having a child diagnosed with autism.

Exposure to lithium in drinking water during pregnancy, which can occur naturally, has been found to increase the risk of autism among children, according to the findings of a new study.

In a report published this week in the medical journal JAMA Pediatrics, Danish researchers indicate mothers who consumed residential water with higher levels of lithium were about 25% more likely to have a child with autism spectrum disorder than their peers.

Lithium is a naturally occurring trace element that has mood-stabilizing effects. It is used to manufacture batteries, grease, and air conditioners. As a drug, it’s used as a treatment for bipolar disorder and other health conditions, but the levels of lithium in drinking water is not regulated. In some animal studies, lithium exposure during pregnancy has been shown to cause neurodevelopment side effects in offspring.

In this new study, researchers conducted a national population-based case-controlled study including 8,800 children diagnosed with autism born from 2000 through 2013. They were compared to 43,800 control participants matched by birth year and sex from the Danish Medical Birth Registry.

The study used geocoded residential maternal addresses during pregnancy, and linked them to lithium levels in their drinking water based on 151 measurements taken from waterworks across all regions in Denmark. Lithium levels were measured from 0.6 to 30.7 ng/L.

According to the findings, maternal exposure to higher levels of lithium in drinking water during pregnancy was linked with a moderate increase in autism in children.

Researchers classified the lowest exposure group, or the reference group, as exposure under 7.36 n/gl. Moderate exposure was considered 7.36 to 12.67 n/gl. The highest risk was above 16.78.

Overall, increases in maternal exposure to natural sources of lithium in drinking water were linked with a 24–26% increased risk of autism in children. Offspring born to participants with exposure in the highest group faced a 46% increased risk.

Researchers said the link was strong even after adjusting for socioeconomic factors and air pollution. They could not exactly measure how much tap water the mothers drank, but Denmark has the lowest level of bottled water consumption in Europe, making it more likely women relied on tap water as the source of drinking water.

The researchers cautioned  that the findings do not prove cause and effect relationship between autism and lithium exposure, but do point to a potential link that should be explored further with other studies.

Autism Rates Growing in U.S.

The risk of autism spectrum disorder (ASD) in children has increased by more than 150% in recent years, from 1-in-44 children in the U.S. in 2021 to 1-in-36 children in the U.S., according to previous studies.

The exact cause of autism in children is still not known, but prior research has linked environmental causes, toxins, and medications to increased risk. One study linked epidurals during pregnancy to an increased risk of ASD, while other research implicates exposure to pesticides and other chemicals, like Roundup.

Other recent studies indicate children born to women who took Tylenol during pregnancy have a higher risk of developing autism and ADHD.

More than 100 families of children with autism and ADHD are now pursuing lawsuits against manufacturers and major retailers nationwide. The lawsuits allege manufacturers failed to warn women of the risks linked with taking the medication during pregnancy.