Investigation Finds Maternal Prenatal Exposure Is Associated with a 23% Increase Risk of ASD in Offspring
According to a new population-based, case-control study from Denmark, pregnant women whose household tap water had higher lithium levels experienced a moderately higher risk of autism spectrum disorder (ASD) in their offspring. The authors believe their research is the first to identify naturally occurring lithium in drinking water as a possible environmental risk factor for autism. The current study included 8842 children born from 2000 through 2013 that received an ASD diagnosis, along with 43,864 control participants matched by birth-year and sex from the Danish Medical Birth Registry. The authors then geocoded all maternal residential addresses in the Danish Civil Registration System from 9 months before until 9 months after pregnancy. The study’s design also controlled for maternal characteristics, some socioeconomic factors, and air pollution exposures. The study’s key finding demonstrated that as lithium levels in drinking water increased, so did the risk of autism diagnosis in pregnant women’s offspring. The authors also discovered the association between lithium levels and autism risk was slightly more substantial for families living in urban areas compared to smaller towns and rural areas. It is worth noting that Denmark’s consumption of bottled water is among the lowest in Europe. Interestingly, lithium concentrations in Danish drinking water (range 0.6-30.7 μg/L) were similar to those reported in U.S. drinking water. One of the study’s authors, David Bellinger, Ph.D., MSc, of Boston Children’s Hospital and Harvard Medical School, pointed out that lithium levels will likely increase worldwide due to mining to produce lithium-ion batteries for the growing number of electric vehicles. Due to the production of these batteries, excess lithium will eventually enter the waste stream. It could contribute to lithium contamination of water supplies, which may increase the risk of autism in the future.
