title: The ratio of 2nd and 4th digit length in autistic children.
abstract: OBJECTIVE
  To compare 2D:4D ratios of autistic to non-autistic children as a risk factor of autism.
  
  
  METHODS
  A hospital based case-control study was conducted from March 2007 to July 2008. Demographic data and general risk factors of autism had been collected using questionnaires from case and age matched control subjects aged 18 months to 15 years. Length of 2nd and 4th digits was measured by an electronic digital caliper.
  
  
  RESULTS
  The ratio of right hand 2D:4D of autistic children was 0.99 +/- 0.06 compared with 1.02 +/- 0.04 of non-autistic children (p = 0.01). On the other hand, 2D:4D ratio of left hand of autistic children was 0.99 +/- 0.07 while the ratio of non-autistic children was 1.01 +/- 0.03 (p = 0.04). The 2D:4D ratio of both hands between 0.96 and 1.01 were risk factors of autism with odds ratio between 3.22 and 5.35 (p < 0.05).
  
  
  CONCLUSIONS
  The ratios of 2D:4D of both hands of autistic children were lower [corrected] than non-autistic children. The ratios of 2D:4D between 0.96 and 1.01 of both hands associated with an increased risk of autism in children aged 18 months to 15 years.
authors.affiliation: Department of Pediatrics, Bangkok Metropolitan Administration Medical College and Vajira Hospital, Bangkok, Thailand.
authors.forename: Pongsak
authors.initials: P
authors.lastname: Noipayak
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D001321:Autistic Disorder / Q000453:epidemiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D006801:Humans; D007223:Infant; D008297:Male; D016017:Odds Ratio; D012372:ROC Curve; D012016:Reference Values; D018570:Risk Assessment; D013223:Statistics as Topic; D011795:Surveys and Questionnaires; D013739:Testosterone / Q000097:blood*; D013785:Thailand / Q000453:epidemiology
chemical_list: D013739:Testosterone