Doctors examine baby teeth for exposure to various metals
For decades, researchers have been trying to find out why some children develop autism. There are even cases where one twin develops the disease, but the other twin is completely healthy. Doctors have now found that baby teeth can provide clues as to whether children are at increased risk of developing autism.
The researchers at the Icahn School of Medicine found that some babies' teeth were exposed to different metals. This could explain why affected children have an increased risk of autism. The doctors published the results of their study in the journal "Nature Communications".
Metals ingested affect various stages of a child's development
In their current investigation, the experts highlighted some possible factors for the risk of autism. These seem to be revealed through children's teeth. The researchers came to this conclusion when examining the baby teeth of 32 twins. It has been found that increased concentrations of lead and other metals are associated with an increased risk of developing autism, the doctors explain. These metals can lead to changes in various stages of a child's development.
One to two percent of all children in Europe suffer from an autism spectrum disorder
A so-called autism spectrum disorder affects one to two percent of all children in Europe and North America, the authors of the study explain. Although much research has been done in this area, there have been few studies to date on how specific environmental factors can affect the risk of autism.
Does autism start in the womb?
We believe that autism begins very early, most likely in the womb, the researchers explain. The results of the study indicate that this risk for children can be increased by environmental influences. When the disease is diagnosed at three or four years old, it is difficult to find out what environmental factors the mother was exposed to. By examining baby teeth, it seems that it is possible to determine exactly this, the authors add.
Researchers perform a metal analysis
Physicians have developed a method to measure children's exposure to lead and other metals by examining baby teeth while they are still in the womb. With the help of a laser, the experts extracted precise layers of dentin (a hard substance under the tooth enamel) for a metal analysis.
Exposure to metals can be determined by examining the teeth
In contrast to genes, our environment is constantly changing, say the doctors. The response of our body to certain environmental factors depends not only on how many factors we were exposed to, but also at what age we experienced this exposure, the scientists explain. The researchers examined metals that are important nutrients for the human body (such as zinc and manganese) and toxic metals such as lead. Through their investigation, the experts were able to estimate at what point in development the children were exposed to certain metals and how strong this exposure was.
How common were autism spectrum disorders during the study?
Of the 32 pairs of twins examined, six had a twin with an autism spectrum disorder. In seven cases, both twins had an autism spectrum disorder. 19 children were not affected by the disease.
Lead and manganese affect the risk of autism
The researchers found only minor differences in the metal intake pattern when both twins had autism. However, they found significant differences in twin pairs, in which only one twin was diagnosed with autism. Differences in the concentrations of six metals were found, including lead, zinc, tin, chromium and manganese. Both lead and manganese are directly related to the risk of autism, the authors explain.
When were the concentrations of lead greatest?
The levels of lead found - from ten weeks before birth to 20 weeks after birth - were consistently elevated in children with an autism spectrum disorder. The biggest difference was observed 15 weeks after the twins were born. The lead values were 1.5 times higher in children with autism spectrum disorder than in their twins, the scientists explain.
Manganese levels are lower in children with an autism spectrum disorder
Manganese levels were lower in children with an autism spectrum disorder ten weeks before birth and 5 to 20 weeks after birth. The biggest difference was found at the age of 15 weeks, when the manganese level in autism spectrum disorders was 2.5 times lower, the scientists report. (as)