Ferritin and hyperactivity ratings in attention deficit hyperactivity disorder

Abstract

Background Iron is a co-factor of tyrosine hydroxylase which is a critical enzyme in dopamine synthesis. Dopamine has been implicated in the pathophysiology of ADHD. Our objective was to investigate the association of ferritin level with parent and teacher ratings and cognitive measures after controlling for age, gender, ADHD subtype, comorbid conditions, hemoglobin, mean corpuscular volume and reticulosite distribution width in a large sample. Methods The study included 713 children and adolescents with ADHD (613 males; age 7–15). Conners Parent Rating Scale (CPRS) and Conners Teacher Rating Scale (CTRS) were obtained. In a subgroup of patients we conducted Digit Span, Digit Symbol, Trail Making Tests as measures of attention and executive functioning. Results Multiple regression analysis indicated that CPRS Hyperactivity score was significantly associated with ferritin level (B=−.12; t=−3.1; p:.002). Other CPRS and CTRS scores as well as cognitive measures were not associated with ferritin level. Conclusions Although it is not possible to make an inference on causality in cross-sectional studies, the results of this largest scale cross-sectional field study to date suggest that lower ferritin level might be associated with parent-reported hyperactivity after controlling for important confounding factors.

Iron Deficiency Parameters in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder

“…Consistent with our study, four other studies reported that ADHD hyperactivity symptom severity were negatively correlated with serum ferritin levels [19,35,37,38]. While one of these four studies found that serum ferritin levels were related with SNAP-IV (Swanson, Nolan and Pelham ADHD rating scale, version IV) hyperactivity/impulsivity score [19]; which was consistent with our study, other studies reported that ferritin levels were only related with the CPRS-Hyperactivity score [35,37,38]. However, the ADHD patients included in these studies were not pure ADHD and they had accompanying psychiatric comorbidities.…”

“…Serum ferritin levels were reported to be negatively correlated with CPRS-Cognitive scores in one study [16], with the CPRS-ODD score in another study [18], with CPRS and CTRS-Total score in a third study [34], and with the CPRS-ADHD Index score in a fourth study [36]. Consistent with our study, four other studies reported that ADHD hyperactivity symptom severity were negatively correlated with serum ferritin levels [19,35,37,38]. While one of these four studies found that serum ferritin levels were related with SNAP-IV (Swanson, Nolan and Pelham ADHD rating scale, version IV) hyperactivity/impulsivity score [19]; which was consistent with our study, other studies reported that ferritin levels were only related with the CPRS-Hyperactivity score [35,37,38].…”

“…However, the ADHD patients included in these studies were not pure ADHD and they had accompanying psychiatric comorbidities. In two of these studies, comorbidity was controlled by using multiple regression analysis [35,38]; whereas, in the other two of these studies, the fact that the possible effect of the comorbidity on the variables was not evaluated draws attention [19,37]. It is not fully known whether comorbid psychiatric disorders influence serum ferritin levels or whether there is a relationship between ferritin and ADHD symptom severities.…”

“…Some studies have shown a significant relationship between serum ferritin levels and the severity of ADHD symptoms [16,18,19,[34][35][36][37][38], while others have not [15,20,24,25,27,39].…”

Vitamin B12 and haemoglobin levels may be related with ADHD symptoms: a study in Turkish children with ADHD

“…We found a positive correlation between psychosomatic subscale of CPRS and ferritin. Other studies reported the relationship between the ADHD hyperactivity scores on Conners scale and low ferritin levels in their ADHD group [15][16][17]. Moreover, the results of the case control studies searching ferritin levels differ from each other.…”