Researchers out of Denmark have found an association between maternal prenatal exposure to naturally occurring lithium in drinking water and a moderate increased risk of autism spectrum disorder (ASD) in offspring, according to a study published today in JAMA Pediatrics. 

According to an article in Newswise, the study is “believed to be the first to identify naturally occurring lithium in drinking water as a possible environmental risk factor for autism.”

Newswise Latest News: news and press releases in science, medicine, life, and business.

 

The team analyzed lithium levels in 151 public waterworks, which make up about half of the entire country’s waterworks. The team noted each mother’s address at the time of pregnancy and accounted for any moves they may have made. It’s worth noting that the study’s authors assume that lithium level estimates in Denmark’s drinking water are generally stable over time, as well. This means the exposure was also consistent. 

Further, they found that ASD is four times more common in males than females in Denmark—with slightly stronger associations between ASD and mothers and children living in urban centers versus rural or provincial areas. People with ASD were also found to have a smaller birth weight than the control participants. 

 

What is lithium?

 

Lithium is a naturally-occurring alkali metal found in some groundwater when water interacts with minerals containing lithium or saline water. The study team stated that groundwater is the source of all drinking water in Denmark and that lithium is a naturally occurring and trace element found in it. 

Lithium is no stranger to the medical world. In the form of carbonate, lithium is commonly used as a pharmaceutical in the psychiatric treatment of conditions like bipolar disorder (BPD) and schizophrenia.

Szklarska D, Rzymski P. Is lithium a micronutrient? From biological activity and epidemiological observation to food fortification. Biol Trace Elem Res. 2019;189(1):18-27.

 

It is typically used for mania and mood instability and is considered a first-line treatment in these cases. It’s also used as an off-label treatment for major depressive disorder as an additional therapy, BPD without mania, vascular headaches, and neutropenia.

Chokhawala K, Lee S, Saadabadi A. Lithium. In: StatPearls. StatPearls Publishing; 2023.

 

 

More so, researchers have theorized that naturally occurring lithium in drinking water may also reduce the risk of suicide at the population level, particularly in areas where the suicide rate is high, according to an analysis in the British Journal of Psychiatry. (It’s also important to note that other research has found a potential inverse relationship between suicidality and lithium use.)

Kawada T. Lithium in drinking water and suicide risk. EXCLI J. 2022;21:571-572.

 

In short, lithium’s therapeutic capabilities are limited, according to the National Center for Biotechnology Information.

Chokhawala K, Lee S, Saadabadi A. Lithium. In: StatPearls. StatPearls Publishing; 2023.

This is because it can cause multiple side effects. It is also contraindicated in pregnant women, as it is thought to increase the risk of congenital disabilities.

Szklarska D, Rzymski P. Is lithium a micronutrient? From biological activity and epidemiological observation to food fortification. Biol Trace Elem Res. 2019;189(1):18-27.

For example, in a study published in Environment International, researchers looked at 194 mother-child pairs in a region of Argentina with high to varying levels of lithium found in the drinking water. It was found that higher levels of lithium in maternal blood and urine were associated with impaired fetal size.

Harari F, Langeén M, Casimiro E, et al. Environmental exposure to lithium during pregnancy and fetal size: a longitudinal study in the Argentinean Andes. Environ Int. 2015;77:48-54.

 

 

Should people be concerned about their drinking water?

 

“Any drinking water contaminants that may affect the developing human brain deserve intense scrutiny,” lead study author Beate Ritz, MD, PhD, professor of neurology in the David Geffen School of Medicine at UCLA and professor of epidemiology and environmental health at the UCLA Fielding School of Public Health, told Newswise. 

“In the future, anthropogenic sources of lithium in water may become more widespread because of lithium battery use and disposal in landfills with the potential for groundwater contamination,” she said. 

Samuel Mowerman, MD, assistant professor of psychiatry at the University of Miami Miller School of Medicine, told MDLinx that he also thinks the study was limited. He says the study’s limitations include a lack of diversity as well as information around lifestyle factors. The study does acknowledge this lack of lifestyle information, although the authors also wrote, “there are no established lifestyle risk factors for autism.” Mowerman also says the study did not account for other medications the subjects may have taken. 

“I also wouldn’t want this study to give a bad rap to lithium as a prescribed medication, as it really is the number one medication for bipolar disorder,” Mowerman adds, saying physicians shouldn’t let this prevent them from prescribing lithium to patients who need it without further information. 

Ritz also says further research is needed before physicians will know how to apply this information to patient care.