Published online February 29, 2008
PEDIATRICS Vol. 121 No. 3 March 2008, pp. 651-652 (doi:10.1542/peds.2007-2996)

This Article Extract Full Text (PDF) Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Cusick, S. E. Articles by Grummer-Strawn, L. Search for Related Content PubMed PubMed Citation Articles by Cusick, S. E. Articles by Grummer-Strawn, L. Related Collections Blood Social Bookmarking                         What's this?

LETTER TO THE EDITOR

Iron-Status Indicators

Sarah E. Cusick, PhD
National Center for Chronic Disease Control and Health Promotion
Division of Nutrition, Physical Activity and Obesity

Anne C. Looker, PhD
National Center for Health Statistics
Division of Health and Nutrition Examination Statistics

Mary E. Cogswell, DrPH, RN
National Center on Birth Defects and Developmental Disabilities
Division of Birth Defects and Developmental Disabilities

Christine M. Pfeiffer, PhD
National Center for Environmental Health
Division of Laboratory Sciences

Laurence Grummer-Strawn, PhD
National Center for Chronic Disease Control and Health Promotion
Division of Nutrition, Physical Activity and Obesity
Centers for Disease Control and Prevention
Atlanta, GA 30333

To the Editor.—

We wish to clarify the statement made in a recent article by Brotanek et al¹ that iron status indicators are no longer available for children <3 years of age beginning with the 2003–2004 cycle of the National Health and Nutrition Examination Survey (NHANES). Although transferrin saturation (TS) and erythrocyte protoporphyrin (EP) were not assessed in children aged 1 to 2 years beginning with the 2003–2004 cycle, ferritin and complete blood count (CBC) data remain available, and a new indicator, soluble transferrin receptor (sTfR), was added.

This change in iron-status indicators collected in the NHANES enables the application of a new model to identify iron deficiency. This model, proposed by Cook et al,² uses the ratio of sTfR, an indicator of tissue iron availability, to ferritin, an indicator of iron storage, to measure body iron stores across the spectrum of iron status. The Centers for Disease Control and Prevention (CDC) previously assessed iron deficiency among NHANES participants by using the ferritin model (at least 2 of 3 abnormal values in ferritin, TS, and/or EP).³ The change to the body iron store model is consistent with expert advice from a workshop convened by the CDC in 2005 and also with the recommendation of a 2004 World Health Organization/CDC consultation on the assessment of iron status of populations.⁴

To phase in the new model, the CDC added sTfR to the existing battery of iron-status indicators measured in the NHANES (ie, ferritin, TS, EP, CBC) beginning in 2003–2004. All 4 indicators were measured in children aged 3 to 5 years and women aged 12 to 49 years through the 2005–2006 cycle, after which TS and EP were phased out. Phase-in of the new model was not possible for children aged 1 to 2 years because of the small serum volume available and the concurrent need to add a measure of vitamin D status. Consequently, ferritin, sTfR, and CBC are the only iron-status indicators available for children aged 1–2 y beginning in 2003–2004.

Among children aged 1–2 years, the change to the new model in the 2003–2004 cycle limits direct comparison of the prevalence of iron deficiency as assessed by the 3-indicator model in NHANES 1988–1994. However, comparisons can still be made with ferritin and CBC data. The CDC continues to recognize the importance of monitoring iron status among US preschool-aged children and women of childbearing age with NHANES data and made the decision to switch to the new model to permit an updated approach for assessing iron status in these vulnerable groups.

REFERENCES

1. Brotanek JM, Gosz J, Weitzman M, Flores G. Iron deficiency in early childhood in the United States: risk factors and racial/ethnic disparities. Pediatrics.2007; 120 (3):568 –575[Abstract/Free Full Text]

2. Cook JD, Flowers CH, Skikne BS. The quantitative assessment of body iron. Blood.2003; 101 (9):3359 –3364[Abstract/Free Full Text]

3. Looker AC, Dallman PR, Carroll MD, Gunter EW, Johnson CL. Prevalence of iron deficiency in the United States. JAMA.1997; 277 (12):973 –976[Abstract/Free Full Text]

4. World Health Organization/Centers for Disease Control and Prevention. Assessing the iron status of populations: a report of a joint World Health Organization/Centers for Disease Control technical consultation on the assessment of iron status at the population level. Available at: http://whqlibdoc.who.int/publications/2004/9241593156_eng.pdf. Accessed January 4,2008

---

PEDIATRICS (ISSN 1098-4275). ©2008 by the American Academy of Pediatrics

CiteULike    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This Article Extract Full Text (PDF) Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Cusick, S. E. Articles by Grummer-Strawn, L. Search for Related Content PubMed PubMed Citation Articles by Cusick, S. E. Articles by Grummer-Strawn, L. Related Collections Blood Social Bookmarking                         What's this?