Is screening for iron deficiency anemia at both ages 12 and 24 months a bedrock part of preventive medicine or a poor use of resources? Although national data is unavailable on rates of screening 1, collegial conversations suggest that many pediatricians practicing in affluent areas without an onsite laboratory have long ago concluded that the routine complete blood count at age one year is neither well accepted by parents nor very informative. While many pediatricians serving families of lower socioeconomic levels linked to academic centers routinely test for anemia when screening for lead exposure per Centers for Disease Control recommendations the question remains, who is best serving the child and family? The recent US Preventive Task Force (USPTF) Recommendations on screening for iron deficiency anemia in healthy asymptomatic young children give us an extraordinarily well researched answer: there is not enough evidence to know.1 While intellectually unsatisfying, because we all hope for an “ah-ha” bottom line, this report gives great “food for thought” for all practitioners.
It is uncomfortable that many of our practices are insufficiently evidence based, based on limited studies that are not generalizable to the populations we serve, or are habits based on personal advice from a trusted mentor. What a great opportunity this represents to do a national study, perhaps involving the American Academy of Pediatrics (AAP) Pediatric Research in Office based Settings (PROS- https://www2.aap.org/pros/ ), that is designed and powered to answer the simple questions we still cannot conclusively resolve. National rates of screening are not known, so who is screening, when and why? Is there a possibility that some children in the US with asymptomatic iron deficiency, perhaps a well-defined at risk subpopulation of these children (for example, those with lead levels 5-10 micrograms/dL living in high poverty census tracts), will have long term benefit from iron supplementation? It will take a lot of collaboration, excellent planning and long term data collection to answer such queries, but in the end the benefits are potentially profound, in terms of children whose outcome is improved, or alternately, who are not exposed to unnecessary testing or attempted treatments.
As a trainee, I well remember learning that the 3 top causes of anemia in children are 1- iron deficiency, 2-iron deficiency, and 3- (yes) iron deficiency. Dr. Siu et al. (doi: 10.1542/peds.2015-2567) at the USPFT reference data from a prior AAP statement which clearly contradicts this information.1,2 Based on NHANES (National Health and Nutrition Examination Study) data from 1999-2002, only 40% of childhood anemia is due to iron deficiency.2 The NHANES definition of anemia was hemoglobin under 11.0 gm/dL, and iron deficiency was defined as an abnormal value for two of three recognized indicators (serum ferritin, zinc protoporphyrin, and transferrin saturation). Whether this is true a decade later, or whether perhaps even fewer cases of anemia are due to iron deficiency now thanks to increasing fortification of food products and formula, is not discussed, but certainly is of interest to those who choose to continue screening. The USPTF guidelines do not address the issue of identifying iron deficiency in the presence of hemoglobin less than 11.0 gm/dL: are red blood cell indices or a reticulocyte hemoglobin or other more expensive add on tests needed or useful? Given the study findings, this question is moot, but likely will continue to bedevil those who feel strongly about continued screening until there is definitive evidence about the impact of treatment.
With estimated US national rates of 8% for iron deficiency and 1-2% for iron deficiency anemia among infants and toddlers, it is unlikely this issue will go away quietly.3 The work of Siu and colleagues at the USPSTF is a refreshing and transparent starting point for new thinking about iron deficiency anemia in young children.
1. Siu et al. Screening for Iron Deficiency: Anemia in Young Children USPSTF Recommendation Statement. Pediatrics 2015, doi: 10.1542/peds.2015-2567 Epub 2015 Sept. 7
2. Baker RD, Greer FR; Committee on Nutrition American Academy of Pediatrics. Diagnosis and prevention of iron deficiency and iron-deficiency anemiain infants and young children (0-3 years of age). Pediatrics. 2010;126:1040-50. doi: 10.1542/peds.2010-2576. Epub 2010 Oct 5.