Children born to mothers whose household tap water has higher levels of naturally occurring lithium may have a higher risk of being diagnosed with autism spectrum disorder, a study in JAMA Pediatrics has found.
Zeyan Liew, Ph.D., M.P.H., of Yale School of Public Health and colleagues analyzed data from 8,842 children in Denmark with autism spectrum disorder and 43,864 of their peers without the disorder. All of the children were born from 2000 through 2013 and were followed to 2016. The researchers measured the concentration of lithium in 151 Danish public waterworks and used the addresses where the mothers lived while pregnant to determine which water source supplied the household at the time. The researchers then divided the lithium concentrations in the water into quartiles (four equal parts) and determined prenatal lithium exposure for each quartile.
The researchers found that the risk of having children with an autism diagnosis rose in relation to the amount of lithium in the household tap water where the mothers lived while pregnant. Compared with mothers in the lowest quartile of exposure, those in the top quartile of exposure had 46% higher odds of having children with autism spectrum disorder. Mothers who had the second and third highest exposures during pregnancy had a 24% and 26% higher odds, respectively, of having children with autism spectrum disorder.
The researchers noted that lithium occurs naturally and is present in drinking water at low concentrations because of the weathering of minerals in the earth. They added that they did not have data on whether the mothers took lithium medications while pregnant, but that the prevalence of such use is usually lower than .1% and is unlikely to be associated with lithium in drinking water.
“[Our] observations call for additional epidemiological studies to examine lithium exposure related [autism spectrum disorder], as well as adverse fetal development, including studies that address dose response and gestational timing of exposures,” the researchers wrote.
For related information, see the American Journal of Psychiatry article “Lithium Exposure During Pregnancy and the Postpartum Period: A Systematic Review and Meta-Analysis of Safety and Efficacy Outcomes.”
(Image: iStock/banusevim)
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