A study led by an Indian-origin researcher has found that baby teeth with more toxic lead and less of essential nutrients such as zinc and manganese may predict autism. The findings showed that children with autism had higher levels of lead throughout development, and lower levels of manganese, both before and after birth. Researchers said lower levels of zinc was observed earlier in the womb, but these levels then increased after birth. The study suggest that differences in early-life exposure to metals, or more importantly how a child’s body processes them, may affect the risk of autism. Lead author Manish Arora, environmental scientist and dentist at the Icahn School of Medicine at Mount Sinai in New York said autism is a condition where both genes and environment play a role, but figuring out which environmental exposures may increase risk has been difficult. Researchers said, the method of using baby teeth to measure past exposure to metals also holds promise for other disorders, such as attention deficit hyperactivity disorder (ADHD). “There is growing excitement about the potential of baby teeth as a rich record of a child’s early life exposure to both helpful and harmful factors in the environment,” explained David Balshaw, from the National Institute of Environmental Health Sciences (NIEHS), under the National Institutes of Health.