Iron deficiency and sleep disordered breathing in children--cause or effect?

Objective: Iron deficiency is associated with paediatric sleep disturbances; in particular, restless leg syndrome (RLS) and periodic limb movement disorder (PLMD). Correction of iron deficiency has been shown to improve sleep disordered breathing (SDB) in certain adult populations. We evaluated the iron status of children diagnosed with SDB undergoing adenotonsillectomy.

Methods: Consecutive children undergoing adenotonsillectomy for SDB between January 2007 and January 2008 were analysed. Routine blood tests were performed including full blood count and iron studies. Children were grouped according to age; 0-2 years (group A), 2-6 years (group B) and above 6 years (group C). Results were compared to local normal values and published data regarding normal values for paediatric populations.

Results: 94 children were included (60 male, 34 female). Mean age was 3.9 years (range 1.2-13.4 years). Iron deficiency was most marked in group A (n=8), with levels of ferritin (12.4), Mean Cell Haemoglobin (MCH) (25.0), iron saturation (16%, normal 20-40%) all below normal and Hb at the bottom of the normal range (11.0, normal 11-14.5). In group B (n=76), ferritin (19.4) and MCH (26.5) were again below normal but were higher than for group A. Average Hb for group B was 11.9.

Conclusion: The association between low iron and SDB in children has not previously been described. The results of this study highlighted low iron status in the children undergoing adenotonsillectomy for SDB. This was most severe in children under 6 years old. It is unclear whether low iron levels represent a cause or effect of SDB.