Neonatal hyperbilirubinemia and risk of autism spectrum disorders.
OBJECTIVE
To investigate the association between neonatal hyperbilirubinemia and autism spectrum disorders (ASD).


METHODS
We conducted a large case-control study nested within the cohort of singleton term infants born between 1995 and 1998 at a northern California Kaiser Permanente hospital. Case subjects (n = 338) were children with an ASD diagnosis recorded in Kaiser Permanente outpatient databases; control subjects (n = 1817) were children without an ASD diagnosis, who were randomly sampled and frequency-matched to case subjects according to gender, birth year, and birth hospital.


RESULTS
Approximately 28% of case and control subjects received > or =1 bilirubin test in the first 30 days of life. No case-control differences were observed for maximal bilirubin levels of > or =15 mg/dL (10.1% vs 12.1%), > or =20 mg/dL (2.1% vs 2.5%), or > or =25 mg/dL (0.3% vs 0.2%). Compared with children whose maximal neonatal bilirubin levels were <15 mg/dL or not measured, children with any degree of bilirubin level elevation were not at increased risk of ASD, after adjustment for gender, birth facility, maternal age, maternal race/ethnicity, maternal education, and gestational age (for bilirubin levels of 15-19.9 mg/dL: odds ratio: 0.7; 95% confidence interval: 0.5-1.2; for bilirubin levels of 20-24.9 mg/dL: odds ratio: 0.7; 95% confidence interval: 0.3-1.6; for bilirubin levels of > or =25 mg/dL: odds ratio: 1.1; 95% confidence interval: 0.1-11.2).


CONCLUSIONS
These data suggest that neonatal hyperbilirubinemia is not a risk factor for ASD.
Croen
Lisa A
LA
Kaiser Permanente, Division of Research, 2000 Broadway, Oakland, CA 94612, USA. lisa.a.croen@kp.org
Yoshida
Cathleen K
CK
Odouli
Roxana
R
Newman
Thomas B
TB
D000328:Adult; D020817:Asperger Syndrome / Q000209:etiology; D001321:Autistic Disorder / Q000209:etiology; D001663:Bilirubin / Q000097:blood; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000209:etiology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007231:Infant, Newborn / Q000097:blood; D007567:Jaundice, Neonatal / Q000150:complications*; D008297:Male; D008423:Maternal Age; D016017:Odds Ratio; D012307:Risk Factors
D001663:Bilirubin