Natural contaminants in drinking water linked to autism

Drinking Water

A UCLA-led study has found a link between increased lithium levels in tap water and a higher risk of autism spectrum disorders in the offspring of pregnant women who are exposed to it. Higher lithium levels were associated with a 46% higher risk of autism than lower levels.

For the first time, researchers are reporting a possible link between autism and lithium in the water supply.

A study conducted by a UCLA A health researcher has found that pregnant women exposed to higher levels of lithium in their tap water had a moderately increased risk of their offspring being diagnosed with autism spectrum disorder. This is the first study to identify naturally occurring lithium in drinking water as a possible environmental risk factor for autism. As lithium levels increased, the risk of an autism diagnosis also increased, with the highest quartile showing a 46% higher risk compared to the lowest quartile. The researchers controlled for a variety of factors, including maternal characteristics, socioeconomic factors, and exposures to air pollution. The results are based on high-quality Danish data and should be replicated in other populations around the world.

Pregnant women whose household tap water had higher levels of lithium had a moderately higher risk of their offspring being diagnosed with autism spectrum disorder, according to a new study led by a health researcher from the University of California to Los Angeles (UCLA).

The study, published April 3 in JAMA Pediatricsis believed to be the first to identify naturally occurring lithium in drinking water as a possible environmental risk factor for autism.

“All drinking water contaminants that may affect human brain development deserve careful consideration,” said study lead author Beate Ritz, MD, PhD, professor of neurology at the David Geffen School. of Medicine at UCLA and Professor of Epidemiology and Environmental Health at UCLA. Fielding School of Public Health. “In the future, anthropogenic sources of lithium in water may become more prevalent due to the use and disposal of lithium batteries in landfills with the potential for groundwater contamination. The results of our study are based on high-quality Danish data but need to be replicated in other populations and regions of the world.

Due to the mood-stabilizing effects of lithium, certain lithium compounds have long been used as treatments for depression and bipolar disorder. However, there has been debate over whether mothers can safely take lithium during pregnancy as there is growing evidence that it is associated with a higher risk of miscarriage and abnormalities or heart defects in newborns.

Ritz, whose research focuses on how environmental exposures influence neurodevelopmental disorders and neurodegenerative diseases, said she decided to examine the possible association between lithium and autism risk after discovering that there had been little research in humans on how lithium affects brain growth and development. Yet she found that some experimental research indicated that lithium, which is one of several natural metals often found in water, may affect an important molecular pathway involved in neurodevelopment and autism.

Zeyan Liew, PhD, MPH, study first author and assistant professor of epidemiology at Yale University School of Public Health, added that this study was important because previous research results from Denmark using high-quality medical registry data have already shown that chronic, low-dose lithium ingestion from alcohol can influence the onset of neuropsychiatric disorders in adulthood. However, no studies have been conducted to assess whether lithium from drinking water consumed by pregnant women affects the neurological development of their child.

Ritz and Liew worked with Danish researchers who analyzed lithium levels in 151 public aqueducts in Denmark, representing the water supply of about half of the country’s population. To identify the water supply stations that supplied the homes of mothers at the time of their pregnancy, the researchers used address information from Denmark’s comprehensive civil registration system. Using a national database of patients with psychiatric disorders, researchers identified children born between 1997 and 2013 and compared 12,799 autism diagnoses to 63,681 children who did not have an autism diagnosis. ‘autism. The researchers also controlled for maternal characteristics, certain socioeconomic factors and exposures to air pollution, all of which have been linked to an increased risk of autism in children.

As lithium levels increased, the risk of an autism diagnosis also increased, the researchers reported. Compared to the lowest quartile of recorded lithium levels – in other words, those at the 25th percentile – lithium levels in the second and third quartiles were associated with a 24-26% higher risk of autism. In the highest quartile, the risk was 46% higher than in the lowest quartile.

The researchers found a similar relationship between increased lithium levels and a higher risk of an autism diagnosis when the data was broken down by subtypes of the disorder. They also found that the association between lithium levels and autism risk was slightly stronger for people living in urban areas than in small towns and rural areas.

In addition to Denmark’s comprehensive civil databases which have proven to be invaluable resources for public health researchers, several other factors have made Denmark an ideal location for this study. Bottled water consumption in Denmark ranks among the lowest in Europe, which means Danes rely heavily on tap water. The country also has a robust system for measuring trace metals and other contaminants in their water supply. Ritz said Denmark’s water lithium levels, compared to other countries, are likely in the low to moderate range.

Reference: “Association between estimated geocoded residential maternal exposure to lithium in drinking water and the risk of autism spectrum disorders in children in Denmark” by Zeyan Liew, PhD, MPH; Qi Meng, MSc; Qi Yan, PhD; Jörg Schullehner, PhD, MSc; Birgitte Hansen, Ph.D., M.Sc.; Soren Munch Kristiansen, PhD, MSc; Denitza D. Voutchkova, PhD, MSc; Jørn Olsen, MD, PhD; Annette Kjær Ersbøll, PhD; Matthias Ketzel, Ph.D., M.Sc.; Ole Raaschou-Nielsen, PhD and Beate R. Ritz, MD, PhD, April 3, 2023, JAMA Pediatrics.
DOI: 10.1001/jamapediatrics.2023.0346

Other study authors include Qi Meng and Qi Yan, both from UCLA, and Danish researchers Jörg Schullehner, Birgitte Hansen, Søren Munch Kristiansen, Denitza D. Voutchkova, Jørn Olsen, Annette Kjær Ersbøll, Matthias Ketzel and Ole Raaschou-Nielsen.

Funding: NIH/National Institute of Environmental Health Sciences, Novo Nordisk Foundation Challenge Program

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