Although the prevalence of lead poisoning has steadily decreased since 1988, it remains a public health problem affecting 1.4% of children (Jones, 2009) with known medical and neurodevelopmental consequences. The medical effects include constipation, growth failure, anemia, encephalopathy, hearing loss, seizures, and even death (Chandra,1980). The neurodevelopmental effects include hyperactivity, school failure, aggression, and delinquent behaviors (Chandra, 1980) Elevated lead levels may be seen at older ages and have a more protracted course in children with autism and other developmental disorders who have persistent pica (Shannon, 1996). In the recent past this was a common finding; lead poisoning was reported in 44% of one group of 34 children with developmental differences. (Cohen, 1976) . While the AAP Clinical Report of 2007 recommends consideration of lead testing in the evaluation of children with autism, there is no data regarding the prevalence of elevated lead levels in this population.
Objectives: To explore elevated lead levels in children with autism spectrum disorders.
Methods: Children seen at the University of Rochester in 2006 or 2007 for diagnosis or treatment of Autism, Asperger’s Syndrome and Pervasive Developmental Disorder, not otherwise specified were identified using ICD-9 codes. Charts of 1088 patients were reviewed for age, diagnostic category, DSM IV criteria, cognitive level, GI diagnoses, seizures, sleep problems, pica, picky eating and parent report or other evidence of lead testing . Laboratory data in the electronic medical record was abstracted including lead level.
Results:
Laboratory results of lead measurement were present in 174/1088 records reviewed. The medical history recalled by the caregiver included report of a normal lead level at or below 2 years of age in another 458 children. Of these children, 9 had elevated lead levels (> 10 mcg/dL). Normal lead levels were recorded for 4 children at < 2 years of age who were later documented to have elevated levels at older ages. Overall 0.8% of the total charts reviewed and 1.4% (9 out of 632) of those with any report of lead had an elevated lead levels. There was no association between elevated lead levels and autism spectrum diagnosis, GI symptoms or seizures. Children with lower cognitive levels or a history of pica were significantly more likely to have documented elevated lead levels.
Conclusions: A minority of children with ASD seen in a tertiary care clinic serving a mixed urban/suburban/rural region have had elevated lead levels. However, 9/17 children who had lead levels drawn for pica that persisted beyond 2 years of age demonstrated clinically significant elevation. While a history of environmental risk may allow for targeted lead screening in general pediatric populations, the presence of pica needs to be considered in determining the need for lead screening in children and youth with autism.
Acknowledgements: Partial support from the Haggerty Friedman Foundation.
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