Cases of autism in children have peaked after a surge in the 1990s, a study has concluded.
Almost four in every 1,000 eight-year-old boys and one in 1,000 girls have had autism diagnosed, the analysis of millions of GP records found.
The rate has remained steady since 2004, according to the study in the journal BMJ Open, casting doubt on recent US research that suggested a 78 per cent rise among eight-year-olds between 2004 and 2008.
Brent Taylor, of University College London, who led the study, said that a fivefold increase in the 1990s was “one of life’s mysteries”. About half the increase could be attributed to better diagnosis and more awareness of the condition but the rest remained unexplained, he said.
The study