Introduction ADHD (Attention Deficit Hyperactivity Disorder) is characterised by age-inappropriate symptoms of hyperactivity, impulsivity and inattention. Iron deficiency anaemia (IDA) is the most common nutritional problem in the UK, affecting 8-13% of children1. Serum ferritin, serum iron and transferrin saturation decrease in IDA.
It has been postulated that ADHD is modulated by dopaminergic mesocortical pathways. Iron is a coenzyme in dopaminergic synthesis. Previous research has suggested that low ferritin and IDA may have a role in ADHD2.
Objective To determine whether there is an increased prevalence of IDA in children with ADHD
Method Review of casenotes of 100 ADHD children. 40 cases were suspected to have IDA from history and clinical findings. 38 were included in the review since lab results of 2 children were not available. We reviewed all electronic record letters and laboratory results.
Results 2 children were female and 36 were male, with an age range of 4-14 years (median 7 years). 92% had ADHD and 8% ADD (attention deficit disorder). 17 had poor appetite, 2 had poor weight gain, 1 had food allergy, 1 had nut allergy and 8 of them had significantly reduced appetite with medication. Serum ferritin was low in 50%. The lower limit of the reference range for ferritin in our hospital's lab is 30 ug/ml for males and 13 ug/ml for females; other studies have used a lower limit of 50 ug/ml. Had we used the latter value, more children would have been classified as having a low ferritin.
Serum iron and transferrin saturation were low in 32% and 45% respectively. Full blood count was abnormal in 42%, with MCV low in 40% of these children.
Conclusion There may be an association between IDA and ADHD. It may be useful to screen children with ADHD for iron deficiency anaemia. However this was a small retrospective review. A larger, well-designed prospective study is required.