Researchers Think Baby Teeth Could Offer a Clue Into What Causes Autism

The findings offer some tantalizing clues about the possible causes of autism. Here's what you need to know.

chatnarin-kongsuk/ShutterstockThere are plenty of autism myths floating around, and new findings will debunk at least some of them. A study, published in Nature Communications, found that baby teeth could offer a window into why some kids develop autism and others do not. According to autismspeaks.org, an estimated 1 in 68 children develop autism in the United States, which translates to 1 in 42 boys and 1 in 189 girls.

Researchers from the Icahn School of Medicine at Mount Sinai examined children’s teeth to look for signs of autism and potential risk factors. They specifically looked for exposure to both toxic and nutritional metals (lead and zinc) at various stages in child development, according to abcnews.go.com.

For the study, lead author Manish Arora, PhD, an environmental scientist and dentist, used lasers to extract precise layers of dentine from the baby teeth of 32 sets of twins in Sweden and examined whether levels of lead or other metals had any correlation with an increased risk of autism. Looking at baby teeth that had fallen out allowed them to measure children’s exposure to lead and other metals—including zinc, manganese, tin, chromium, and lead—while they were in the womb and during the early stages of childhood, and the stages of development during which were exposed to those metals.

The team’s findings suggest that one’s early environment has an impact on the risk of developing autism spectrum disorders.

From the baby teeth of the 32 pairs of twins, researchers found six had one twin who had autism, seven had both twins with autism, and 19 did not have autism. Researchers found smaller differences in metal intake when both twins had autism, whereas they found huge differences in pairs when one sibling had autism. They also found both lead and manganese, which were statistically significant in how they related to autism risk. According to the findings, lead levels were consistently higher from 10 weeks before birth to 20 weeks after birth in children with autism spectrum disorder than their non-autism spectrum disorder counterparts. The largest notable difference is that at 15 weeks post birth, lead levels were 1.5 times higher in children with autism spectrum disorder than in their co-twins. In essence, Arora and his team have identified a window of time in the womb as the one during which children are most susceptible to metal exposure and a potential link to autism.

“We think autism begins very early, most likely in the womb, and research suggests that our environment can increase a child’s risk. But by the time children are diagnosed at age 3 or 4, it’s hard to go back and know what the moms were exposed to,” said Cindy Lawler, PhD, head of the NIEHS Genes, Environment, and Health Branch. According to Lawler, baby teeth allow one to do just that.

It is important to note that these results are preliminary and only suggest a connection. It’s also important to note that previous studies have shown mixed results about autism and exposures to metals. In their study of twins, these researchers wanted to remove genetics as a factor for having autism and isolate metal exposures from the environment. They also wanted to answer worried parents’ questions about exposure to metals.

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