Differential ferritin interpretation methods that adjust for inflammation yield discrepant iron deficiency prevalence

Area of Science:

• Nutritional Science
• Pediatric Health
• Biochemistry

Background:

• Iron deficiency (ID) and iron deficiency anemia (IDA) are significant global health concerns, particularly in infants.
• Assessing iron status using serum ferritin (SF) is complicated by inflammation, which can elevate SF levels.
• High prevalence of acute and chronic inflammation was observed in a South African infant trial.

Purpose of the Study:

• To reassess iron deficiency prevalence in South African infants by comparing four inflammation-adjusted methods.
• To evaluate the impact of inflammation on serum ferritin measurements in infant iron status assessment.
• To determine the most reliable method for estimating ID and IDA prevalence in the presence of inflammation.

Main Methods:

• Compared four methods for adjusting serum ferritin (SF) for inflammation: exclusion, higher cut-off, differential cut-offs, and correction factors (CFs).
• Measured SF, alpha-1 glycoprotein, and C-reactive protein in 192 infants (4-13 months old).
• Compared adjusted SF results against a reference method (SF < 12 μg/L) that did not account for inflammation.

Main Results:

• The higher SF cut-off method yielded the highest ID prevalence (52.1%), while excluding inflammation gave the lowest (17.6%).
• The correction factor (CF) method showed the best agreement with the reference method, estimating ID prevalence at 21.9%.
• Disregarding inflammation led to a significantly underestimated ID prevalence (17.2%). IDA prevalence ranged from 13.2% to 24.5%.

Conclusions:

• Serum ferritin alone is insufficient for accurate iron status assessment in infants with inflammation.
• Measuring inflammation markers is essential to correct for their effect on serum ferritin levels.
• Correction factors offer a reliable approach to estimating iron deficiency prevalence in populations with high inflammation rates.