Association between Low Serum Ferritin and Restless Legs Syndrome in Patients with Attention Deficit Hyperactivity Disorder

Abstract

Attention defi cit hyperactivity disorder (ADHD) is a neurobehavioral disorder characterized by pervasive inattention and/or hyperactivity-impulsivity. It has been suggested that ADHD symptoms are associated with restless legs syndrome (RLS), which is a neurological condition that is defi ned by an irresistible urge to move the legs. Increasing evidence suggests iron deficiency may underlie common pathophysiological mechanisms in subjects with ADHD and with RLS. To further defi ne the relationship between iron defi ciency and RLS in children and adolescents with ADHD, we evaluated 87 ADHD subjects: 79 boys and 8 girls with age 9.3 ± 2.5 years (6-16 years). Various psychopathologies and the severity of the ADHD symptoms and serum ferritin levels were assessed. Diagnosis of RLS was made according to the International RLS Group criteria. The patients were evaluated for the iron defi ciency (ferritin < 12 ng/ml). RLS was found in 29 (33.3%) of the 87 ADHD subjects. Parentand teacher-rated behavioral and emotional problems and the severity of ADHD symptoms were not signifi cantly different between ADHD subjects with RLS and those without RLS (n = 58). The rate of iron defi ciency was signifi cantly higher in ADHD subjects with RLS (n = 6, 20.7%) when compared with ADHD subjects without RLS (n = 1, 1.7%, p = 0.005). Our results showed that depleted iron stores might increase the risk of having RLS in ADHD subjects. Iron defi ciency, which is associated with both ADHD and RLS, seems to be an important modifying factor in the relationship between these two conditions. restless legs syndrome; attention defi cit hyperactivity disorder; iron defi ciency; ferritin; dopamine

Prevalence and Clinical Characteristics of the Restless Legs Syndrome (RLS) in Patients Diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) in Antioquia

“…However, making a comparison is a complicated matter because that was a population-based study conducted with RLS patients. In contrast, Oner described 33.3% of definite RLS in patients with ADHD; a value superior to that found in the present work, perhaps due to the usage of scales to diagnose ADHD: Oner used the Kiddie Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL), which somehow varies from the DMS-IV criteria (Oner et al, 2007).…”

Iron Status in Children With Autism Spectrum Disorder

“…40 Several authors have found low SF/ID in children with attention-deficit/ hyperactivity disorder. 18,20,37,41,42 This is not a uniform finding, however. 19 This study has several limitations.…”

“…[18][19][20][21][22][23][24] Dietary inadequacy of iron does not appear to be the only risk factor for low iron stores. Future studies will need to explore the complexity of iron metabolism and include central laboratory testing, markers of inflammation such as C-reactive protein, and other markers of iron absorption.…”

“…Despite concerns about dietary inadequacy and evidence that ID can affect attention, sleep, and cognitive development, [18][19][20][21][22][23][24] no studies in the United States have examined iron status or the relationship between iron intake and iron status in children with ASD. It is important to identify remediable medical risk factors for both behavioral and medical disorders in children with ASD.…”

ADHD and Sleep Problems in Children

“…In a study comparing children referred for clinically defined ADHD versus two other groups, those identified as at risk for ADHD from a community survey and children without ADHD, those with clinically determined ADHD had higher PLMs than the other groups suggesting a greater risk for more active and disrupted sleep (O'Brien, 2003). In addition, in children with ADHD, serum ferritin less than 12 ng/ml was more prevalent in children with RLS symptoms (Oner, 2007). Thus, RLS, PLMS and PLMD appear to be related to daytime ADHD symptoms; however, but further work is needed to clarify the relationship and the role of iron specifically in the etiology and management.…”