Low ferritin has been associated with nighttime waking due to restless leg syndrome in children with autism spectrum disorders (ASD). Two small studies have documented low ferritin levels in children with ASD (Dosman 2007; Latif 2002). Neither of these studies examined pica or ADHD symptoms, although iron deficiency has been related to these (Konofal 2007) in children without ASD. Children with ASD may be at greater risk for low iron stores because of dietary selectivity. This preliminary analysis examines the potential association of ferritin as a measure of decreased iron stores with pica and the behavioral symptomatology of ADHD.
This study will test the hypotheses that:
1). Children with ASD are at risk for iron deficiency as documented by low ferritin levels
2). Low ferritin levels will be associated with the presence of pica
3). Low ferritin levels will correlate with increased scores on the ADHD index and attention subscale of the CBCL
Methods: The Autism Treatment Network (ATN) is a network of 14 academic centers that follow a common assessment protocol to establish a standard of medical care for children with ASD. The clinical charts of 100 children with ASD (ages 2-17) recruited to the University of Rochester ATN site were reviewed for ferritin status. Twenty-four children with ferritin levels and Complete Blood Count drawn in clinical care were identified. Data collected included a standardized parent report of pica, the (CBCL) Child Behavior Checklist (Achenbach 1991) and cognitive levels (Mullen Scales of Early Learning or the Stanford-Binet 5th edition).
Results: The children had a mean age of 7 years 1 month (33 months-13 years 7 months). The mean ferritin level was 25.5ng/mL. Ten children (41.7%) had ferritin levels below the laboratory normal range. Eight of the 24 children (33%) had symptoms of pica. The mean ferritin level for children with pica (24ng/mL) was more than six points below the ferritin level for children without pica (30.7ng/mL) but did not reach clinical significance (p=.41) by t test. However, in a post-hoc exploratory analysis, children with IQ scores below 70 were more likely to have pica (p=0.039). Ferritin levels were not correlated with the ADHD index (p=.402) or attention subscale (p=0.946) on the CBCL. Further, ferritin levels were not correlated with anemia as measured by hemoglobin (p=0.205).
Conclusions: In this small preliminary study, over 40% of the children with ASD were found to have ferritin levels below the normal range. Pica was not associated with ferritin level as a measure of iron status, but was associated with lower cognitive level. No relationship was found between the ferritin level and the ADHD index or attention subscale on the CBCL. The participants in this study may have been selected for laboratory testing because of behavioral or dietary concerns on the part of the clinician. Since children with ASD have limited diets and high rates of pica, evaluation of a larger sample with data related to dietary intake is indicated.