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Haemoglobin and ferritin concentrations in infants at 8 months of age
A M Emond1, N Hawkins, C Pennock
1Institute of Child Health, Royal Hospital for Sick Children, St Michael's Hill, Bristol.
Insights
This study establishes normal ranges for infant haemoglobin and ferritin at 8 months, suggesting current anaemia screening may miss many cases. New cut-offs are proposed for better detection of iron deficiency in infants.
Area of Science:
- Paediatric nutrition and public health
- Iron metabolism and deficiency disorders
- Biomarker analysis in infant populations
Background:
- Iron deficiency anaemia is a significant concern in infancy.
- Accurate screening requires understanding normal biomarker ranges in specific age groups.
- Previous screening recommendations may not reflect current population data.
Purpose of the Study:
- To determine the optimal age for screening iron deficiency.
- To investigate the normal distribution of haemoglobin and ferritin in infants.
- To establish representative cut-off values for anaemia and iron deficiency.
Main Methods:
- Analysis of haemoglobin and ferritin levels from capillary blood samples.
- Study cohort of 1175 infants aged 8 months from the Avon Longitudinal Study of Pregnancy and Childhood.
- Utilized heel prick samples for biomarker measurement.
Main Results:
- Established normal haemoglobin (mean 117 SD 11 mg/dL) and ferritin (geometric mean 38.5 µg/L) ranges.
- Identified the 5th centile for haemoglobin at 97 mg/dL and ferritin at 16.9 µg/L.
- Found ferritin related to birth weight and infant sex, haemoglobin to infant weight, but no social class correlation.
Conclusions:
- Defined normal haemoglobin and ferritin ranges for UK infants at 8 months.
- Current screening criteria identify only 23% of anaemic infants.
- Recommended new cut-offs: haemoglobin < 97 mg/dL and ferritin < 16 µg/L for anaemia and iron deficiency.
Aim:
To identify the optimum age to screen for iron deficiency, the normal distribution of haemoglobin and ferritin in a representative population sample was investigated.
Methods:
Normal values for haemoglobin and ferritin were measured from heel prick capillary samples obtained from a representative cohort of 1175 infants at 8 months old who were randomly selected from children taking part in the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC).
Results:
Haemoglobin was normally distributed: mean (SD) 117 (11) milligrams, 95% confidence interval (CI) 116 to 118, and range 72-153 milligrams. Ferritin was log normally distributed: geometric mean 38.5 micrograms/l, 95% CI 37.0 to 39.9, range 7.1-224 micrograms/l. The 5th centile for haemoglobin was 97 milligrams and for ferritin 16.9 micrograms/l. No correlation was found between haemoglobin and ferritin. Multiple regression analysis showed ferritin concentrations to be positively related to birth weight (p < 0.0001) and the sex of the child (girls with higher concentrations) (p < 0.0001) but negatively with the child's weight at 8 months (p < 0.0001). Haemoglobin concentrations were positively related to the child's weight at 8 months (p = 0.04). Neither haemoglobin nor ferritin concentrations were related to social class as measured by maternal education level.
Conclusion:
These data define the normal range for haemoglobin and ferritin in capillary samples in the UK population, and suggest that anaemia is common in infancy. Using current recommendations, 23% of infants would be identified as anaemic. For British infants at 8 months of age, a more representative 'cut off' for anaemia would be haemoglobin concentration < 97 milligrams and for iron deficiency ferritin < 16 micrograms/l.