Urinary Ferritin as a Noninvasive Means of Assessing Iron Status in Young Children

Najma A Moumin; Nina D'Vaz; Courtney Kidd; Andrea MacRae; Shao J Zhou; Toby Richards; Debra J Palmer; Luke E Grzeskowiak; Thomas R Sullivan; Tim J Green

doi:10.1016/j.tjnut.2024.04.040

Urinary Ferritin as a Noninvasive Means of Assessing Iron Status in Young Children

J Nutr. 2024 May 8:S0022-3166(24)00272-4. doi: 10.1016/j.tjnut.2024.04.040. Online ahead of print.

Authors

Affiliations

¹ Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia; Discipline of Pediatrics, Faculty of Health and Medical Sciences, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia. Electronic address: najma.moumin@sahmri.com.
² Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia; School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia.
³ Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia.
⁴ School of Agriculture, Food & Wine, The University of Adelaide, Urrbrae, South Australia, Australia; Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia.
⁵ School of Medicine, Division of Surgery, University of Western Australia, Perth, Western Australia, Australia.
⁶ Telethon Kids Institute, University of Western Australia, Nedlands, Western Australia, Australia; School of Medicine, University of Western Australia, Crawley, Western Australia, Australia.
⁷ Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia; College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia.
⁸ Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia; Discipline of Public Health, Faculty of Health and Medical Sciences, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.
⁹ Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia; College of Nursing and Health Sciences, Flinders University, Bedford Park, South Australia, Australia.

PMID: 38729575
DOI: 10.1016/j.tjnut.2024.04.040

Abstract

Background: Iron deficiency (ID) is the most common nutritional deficiency affecting young children. Serum ferritin concentration is the preferred biomarker for measuring iron status because it reflects iron stores; however, blood collection can be distressing for young children and can be logistically difficult. A noninvasive means to measure iron status would be attractive to either diagnose or screen for ID in young children.

Objectives: This study aimed to determine the correlation between urinary and serum ferritin concentrations in young children; to determine whether correcting urinary ferritin for creatinine and specific gravity improves the correlation; and to determine a urine ferritin cut point to predict ID.

Methods: Validation study was conducted using paired serum and urine collected from 3-y-old children (n = 142) participating in a longitudinal birth cohort study: the ORIGINS project in Perth, Western Australia. We calculated the sensitivity, specificity, positive, and negative predictive values of urinary ferritin amount in identifying those with ID at the clinical cut point used by the World Health Organization (serum ferritin concentration of <12 ng/mL).

Results: Urine ferritin, corrected for creatinine, correlated moderately with serum ferritin [r = 0.53 (0.40-0.64)] and performed well in predicting those with ID (area under the curve: 0.85; 95% confidence interval: 0.75, 0.94). Urine ferritin <2.28 ng/mg creatinine was sensitive (86%) and specific (77%) in predicting ID and had a high negative predictive value of 97%; however, the positive predictive value was low (40%) owing to the low prevalence of ID in the sample (16%).

Conclusions: Urine ferritin shows good diagnostic performance for ID. This noninvasive biomarker maybe a useful screening tool to exclude ID in healthy young children; however, further research is needed in other populations.

Keywords: Australia; iron status; noninvasive biomarker; serum ferritin; the ORIGINS project; urinary ferritin; young children.