Iron deficiency occurs frequently in children with cystic fibrosis

Abstract

In adult CF patients iron deficiency (ID) is common and primarily functional due to chronic inflammation. No recent data are available on the cause of ID and iron deficiency anemia (IDA) in children with CF. Over the last decades onset of inflammation and pulmonary disease in children with CF is delayed by improved nutritional status. We questioned whether ID occurs in the same extent among children with CF as in adult CF patients. We therefore conducted a study to investigate the iron status of children with CF and to determine whether ID and IDA are associated with dietary iron intake, lung disease severity and Pseudomonas aeruginosa (PA) infection. Clinical charts of 53 children with CF aged 0-16 were reviewed. Follow-up varied from 1 to 14 years with 343 annual observations in total. Thirty-two children (60.4%) were iron deficient in at least 1 year and ID was present in 84 of 343 observations (24.5%). In 2011 ID was present in 9 children (17.0%). Ten children (18.9%) were anemic in at least 1 year and anemia was present in 13 of 328 observations (4.0%). IDA was present in at least 1 year in 6 children (11.3%). Ferritin (Fer) was positively associated with age. Higher Fer values found in older children represent an increased state of inflammation, rather than an improved iron status, and might increase the relative contribution of functional ID. This study shows that ID is common in relatively healthy, well-nourished children with CF. The mechanism of ID in children with CF is currently unknown. A prospective study using both soluble transferrin receptor and Fer as indicators for ID will provide more insight in the incidence and causes of ID in children with CF.

What is hepcidin telling us about the natural history of cystic fibrosis?

“…As Uijterschout et al [8] discovered for soluble transferrin receptor (sTfR), a single blood test is unlikely to distinguish between absolute and functional iron deficiency in the CF population, especially when numerous biochemical criteria (Table 1) have been used to describe these entities. Nonetheless, their use of serum ferritin <12 μg/l in children <5 years of age and <15 μg/l in older children to define iron deficiency is certainly sound and consistent with earlier work [17], adding an invaluable measure of uniformity to the pediatric literature on this topic. Arbitrarily determining cutoffs for various iron-related hematologic parameters, even serum hepcidin-25, may not be the most constructive approach to understanding CF iron homeostasis.…”

Chronic Inflammation and Iron Metabolism

“…The elevated ferritin concentrations likely index a state of inflammation, rather than iron status as evidenced by their relationships to reductions in pulmonary function, increased numbers of pulmonary exacerbations, and higher colonization rates with Pseudomonas aeruginosa . The degree of iron deficiency reported may be an underestimation given that ferritin increases as an acute phase reaction during inflammation 44 . This example highlights the diagnostic and treatment difficulty for clinicians; absolute iron deficiency in a growing child requires supplementation, and functional iron deficiency due to inflammation likely will not respond to iron supplementation because of the high hepcidin state.…”

Perspectives on anemia and iron deficiency from the cystic fibrosis care community

“…To the Editor, Anemia and the related problem of iron deficiency are prevalent in people with cystic fibrosis (PwCF) and are associated with worse lung function in adults 1,2 but curiously not in children. 2,3 Because authors have heterogeneously defined anemia and iron deficiency in CF and humoral inflammatory mediators (i.e., interleukin-6 and hepcidin-25) affect biomarkers of iron homeostasis during CF pulmonary exacerbation (PEx), 4 discourse on these topics has lacked precision and consensus. Although some evidence suggests that oral iron supplementation does not trigger PEx or alter the lung microbiome in PwCF, 5 the adverse potential for this treatment to enhance the growth of airway pathogens concerns some providers.…”