E Mantadakis. J Pediatr 2022; 245: 12-14. (Editorial) Open access. Serum Ferritin Threshold for Iron Deficiency Screening in One-Year-Old Children nutrition.
N Mukhtarova et al. J Pediatr 2022; 245: 217-221. Serum Ferritin Threshold for Iron Deficiency Screening in One-Year-Old Children. This study included 3153 infants, with 698 included in the final analysis.
- 11.4% had iron deficiency, 3.5% had iron deficiency anemia, 8.2% had anemia, and 76.9% were normal.
- “The authors showed that the hemoglobin threshold of 110 g/L that is currently recommended for diagnosing anemia at 1-year-old well-child visit corresponds with a very low serum ferritin (4.42 mcg/L).”
- In a previous study, TARGet Kids!, “a higher serum ferritin was associated with higher cognitive function, with a serum ferritin of 17 mcg/L corresponding with the maximum level of cognition.” That is, iron deficiency, even in the absence of anemia, can contribute to detrimental cognitive outcomes.
- Thus, current hemoglobin levels and ferritin need to be revised. Neither a hemoglobin of 11.0 g/dL nor a ferritin of 12 mcg/L is sensitive in detecting iron deficiency in toddlers.
- In the U.S., only ~40% of anemia in toddlers is attributable to iron deficiency; thus, checking a ferritin can help determine if iron supplementation is worthwhile.
My take: Iron deficiency anemia is a late indicator of iron deficiency and relying on hemoglobin alone could have irreversible detrimental effects on cognitive outcomes. These articles make a strong argument for the following:
- Use a ferritin threshold of at least 18 mcg/L to determine if iron deficient
- Check a ferritin along with a hemoglobin at 1-year well-child check.
Related blog post: Briefly Noted: Ferritin Levels and Cognitive Outcomes