Autism and ADHD are linked to disturbed gut flora very early in life

…The study is part of the ABIS (All Babies in Southeast Sweden) study led by Johnny Ludvigsson at Linköping University. More than 16,000 children born in 1997–1999, representing the general population, have been followed from birth into their twenties. Of these, 1,197 children, corresponding to 7.3 percent, have been diagnosed with autism spectrum disorder, ADHD, communication disorder or intellectual disability. A large number of lifestyle and environmental factors have been identified through surveys conducted on several occasions during the children’s upbringing. For some of the children, the researchers have analysed substances in umbilical cord blood and bacteria in their stool at the age of one.

“We can see in the study that there are clear differences in the intestinal flora already during the first year of life between those who develop autism or ADHD and those who don’t. We’ve found associations with some factors that affect gut bacteria, such as antibiotic treatment during the child’s first year, which is linked to an increased risk of these diseases,” says Johnny Ludvigsson, senior professor at the Department of Biomedical and Clinical Sciences at Linköping University, who led the study together with Eric W. Triplett.

Children who had repeated ear infections during their first year of life had an increased risk of being diagnosed with a developmental neurological disorder later in life. It is probably not the infection itself that is the culprit, but the researchers suspect a link to antibiotic treatment. They found that the presence of Citrobacter bacteria or the absence of Coprococcus bacteria increased the risk of future diagnosis. One possible explanation may be that antibiotic treatment has disturbed the composition of the gut flora in a way that contributes to neurodevelopmental disorders. The risk of antibiotic treatment damaging the gut flora and increasing the risk of diseases linked to the immune system, such as type 1 diabetes and childhood rheumatism, has been shown in previous studies.

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