A study published on April 3 in JAMA Pediatrics is thought to be the first to recognize naturally occurring lithium in drinking water as a potential environmental risk factor for autism. “Any contaminants in drinking water that could impact the developing human brain warrant serious investigation,” stated the lead author of the study, Beate Ritz, MD, PhD, a professor of neurology at the David Geffen School of Medicine at UCLA and a professor of epidemiology and environmental health at the UCLA Fielding School of Public Health.
Ritz noted that in the future, anthropogenic sources of lithium in water could become more common due to lithium battery usage and disposal in landfills, potentially leading to groundwater contamination.
“Our findings are based on high-quality Danish data, but they need to be confirmed in other populations and regions around the globe.”
Lithium compounds have been used to treat depression and bipolar disorders for many years, thanks to their mood-stabilizing properties. However, there is ongoing debate about the safety of lithium consumption during pregnancy, as evidence grows linking it to higher risks of miscarriage and heart abnormalities in newborns.
Ritz, whose research centers on the influence of environmental exposures on neurodevelopmental disorders and neurodegenerative diseases, decided to explore the potential link between lithium and autism risk due to the lack of human research on how lithium impacts brain development and growth.
She discovered that some experimental studies suggested that lithium, one of several naturally occurring metals often found in water, could affect a critical molecular pathway involved in neurodevelopment and autism.
Zeyan Liew, PhD, MPH, the study’s first author and an Assistant Professor of Epidemiology at the Yale University School of Public Health, noted that this research is significant because previous studies from Denmark utilizing high-quality medical registry data have demonstrated that long-term, low-dose lithium ingestion from drinking water can influence the prevalence of adult-onset neuropsychiatric disorders.
No study had yet investigated whether lithium from drinking water consumed by pregnant women impacts their child’s neurodevelopment.
Ritz and Liew collaborated with Danish researchers to analyze lithium levels in 151 public waterworks in Denmark, which supply water to approximately half of the country’s population.
Using Denmark’s extensive civil registry system, the researchers identified which waterworks provided water to the mothers’ homes during their pregnancies.
The researchers used a national database of patients with psychiatric disorders to identify children born between 1997 and 2013. They compared 12,799 children diagnosed with autism to 63,681 children without an autism diagnosis, while accounting for maternal characteristics, socioeconomic factors, and air pollution exposures, all of which have been associated with increased autism risk in children.
The researchers found that as lithium levels increased, so did the risk of autism diagnosis. Compared to the lowest quartile of recorded lithium levels (the 25th percentile), the second and third quartiles were associated with a 24-26% higher risk of autism. In the highest quartile, the risk was 46% higher compared to the lowest quartile.
A similar relationship was observed between higher lithium levels and increased autism diagnosis risk when the data were analyzed by disorder subtypes. The association between lithium levels and autism risk was slightly stronger in urban areas than in smaller towns and rural regions.
Denmark’s comprehensive civil databases, along with other factors, made the country an ideal location for this study. Danes primarily rely on tap water, as Denmark’s bottled water consumption is among the lowest in Europe. Additionally, the country has a robust system for measuring trace metals and other contaminants in its water supply. Ritz mentioned that compared to other nations, lithium levels in Denmark’s water are likely in the low to moderate range.
Key Takeaways in a Nutshell – Health Newstrack
– A study in JAMA Pediatrics suggests that naturally occurring lithium in drinking water may be a potential environmental risk factor for autism.
– Researchers compared children diagnosed with autism to those without an autism diagnosis, finding that increased lithium levels were associated with a higher risk of autism.
– The association between lithium levels and autism risk was slightly stronger in urban areas compared to smaller towns and rural regions.
– Denmark’s comprehensive civil databases, low bottled water consumption, and robust system for measuring trace metals in water made it an ideal location for this study.
– The findings are based on high-quality Danish data, but further research is needed to confirm these results in other populations and regions around the world.