Iron status in young children with Autism Spectrum Disorder : a thesis submitted in partial fulfilment of the requirements for the degree of Masters in Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
Background: Autism Spectrum Disorder (ASD) is diagnosed when a child shows unusual social behaviour, difficulty communicating both verbally and non-verbally, and performing repetitive tasks. Children with ASD often present with unusual feeding patterns and behaviours, and overseas research shows children with ASD are at greater risk of iron deficiency and iron deficiency anaemia. Maintaining adequate iron levels is very important, as during periods of growth and development iron has a role to play in both brain structure and function. Therefore it is important for children to eat foods rich in iron or foods that optimise iron bioavailability. In New Zealand, the prevalence of iron deficiency in children is relatively low, being 1.6%. However, there is no published data on iron status or dietary factors associated with iron status in New Zealand children with ASD.
Objective: To investigate factors influencing iron status in a cohort of children with Autism Spectrum Disorder living in New Zealand.
Methods: Sixty nine children with ASD between the ages of 2.5-8 years took part in this cross-sectional study. Participants were required to complete an estimated four-day food diary, a dietary questionnaire, and a Behavioural Paediatrics Feeding Assessment Scale (BPFAS) questionnaire. Serum ferritin, serum iron, total iron binding capacity, transferrin saturation and haemoglobin were measured to determine iron status. Statistical analysis was performed using independent t-tests, Mann-Whitney, Chi-square and Fishers’ exact test.
Results: Iron depletion was present in 32.9% of the sample population (serum ferritin ≤ 20 μg/L), and iron deficiency was present in an additional 4.3% (serum ferritin ≤ 12 μg/L). No participants had iron deficiency anaemia (serum ferritin SF ≤ 12 μg/L plus Hb ≤ 110 g/L in 1-5 years; or Hb ≤ 115 g/L in 5-8 years). Participants in the iron replete group had significantly higher dietary protein intake (P = 0.003) and vitamin A intake (P = 0.036) compared to iron insufficient participants. The iron insufficient group had a significantly higher BPFAS frequency score than the iron replete group (P = 0.022), and significantly more participants in the iron insufficient group had a BPFAS score ≥84 (P = 0.020), indicating more feeding issues. No differences in patterns or factors affecting dietary intake were seen when comparing iron insufficient and iron replete groups.
Conclusion: Children with ASD in New Zealand appear to be at an increased risk of iron depletion and iron deficiency compared to neuro typical developing children. While no differences in dietary iron intake were seen between the iron replete and iron insufficient groups, iron replete participants had significantly higher intake of protein and vitamin A. More feeding behavioural problems were
identified in the iron insufficient group compared to the iron replete group. Further studies with a larger sample size should be undertaken to investigate other factors (dietary and non-dietary) to establish determinants of iron status in this population.