1. ¹Division of Pediatrics, National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, India
2. ²Division of Biophysics, National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, India
3. ³Division of Statistics, National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, India
4. ⁴Division of Pathology, National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, India

Correspondence: P Bhaskaram, National Institute of Nutrition, Indian Council of Medical Research, Jamai-Osmania PO, Hyderabad-500 007, Andhra Pradesh, India. E-mail: pbhask@yahoo.com

^*Guarantors: P Bhaskaram and K Madhavan Nair.

^†Contributors: PB the principal contributor is responsible for study design, recruitment, follow-up of patients, data interpretation and manuscript preparation; KMN contributed to the study design, data analysis and manuscript preparation; PR contributed to the analysis of iron status parameters. NB carried out statistical analysis of the data and BS contributed to the hematological investigations. All the investigators contributed to the writing of the paper.

Received 25 July 2001; Revised 21 March 2002; Accepted 22 March 2002.

Abstract

Objective: To study the effect of infection on iron status in children suffering from acute, mild or severe respiratory infections and to determine the nature of anemia in infection using serum transferrin receptor (sTfR) levels.

Design: Forty-three children aged between 3 and 5 y with no evidence of infection and receiving iron supplements in the preceding 100 days served as controls. Twenty-one children with mild upper respiratory infection and 94 children hospitalized for acute pneumonia constituted the experimental group. Hemoglobin (Hb), sTfR and serum ferritin were estimated in all the children at the time of diagnosis and again on the 15th and 30th days after the infection in those who were available for follow-up.

Results: Mean (95% CI) sTfR was 6.08 (5.1–7.1) mg/l in healthy non-anemic children. Upper respiratory infection had no impact on Hb or sTfR but it significantly elevated serum ferritin levels. Eighty-three percent of the children with pneumonia had Hb less than 110 g/l at the time of diagnosis and had elevated mean sTfR, 18.0 (15.7–20.3) mg/l. There was a decline in mean sTfR by the 15th day of infection to 14.3 (11.3–17.4) mg/l with further rise to 22.9 (13.0–31.9) mg/l by 30 days. Serum ferritin was significantly elevated at the time of diagnosis (85.9; 71.1–100.8 g/l) as well as at 15 days (89.1; 68–110.1 g/l) with a decline by 30 days.

Conclusion: Severe lower respiratory infection exaggerates iron-deficient erythropoiesis by blocking release of iron from the storage pools. sTfR may not be a sensitive and specific tool of assessing true iron status of children exposed to severe infections.

Sponsorship: Funding from the Department of Science and Technology (DST no. SP/SO/B-29/96), Government of India, New Delhi, India.