Iron deficiency is diagnosed by low levels of ferritin in the blood, a protein which fluctuates in the presence of inflammation. A new study published in the American Journal of Clinical Nutrition determined how to detect iron deficiency in a population of individuals with malaria, while controlling for inflammation-related changes in ferritin.
Iron is essential in the human body to transport oxygen from the lungs to the different tissues. Iron deficiency can interfere with vital functions and lead to sickness and death. Despite its importance, iron deficiency is the most common nutritional deficiency in the world, affecting at least 1.62 billion people worldwide.
Iron levels in the body are currently measured through ferritin concentrations or iron stores, as it is an easy non-invasive measure that responds well to intervention. However, in individuals with high levels of inflammation, ferritin concentrations are impacted by the acute-phase response (APR). APR is an immunologic process that causes acute-phase proteins (APPs) to increase or decrease in response to microbial infection, injury and inflammatory processes. Therefore, ferritin, an APP, can become elevated during inflammation, and is not a reliable marker for iron levels.
In populations with high levels of inflammation, such as those at a high risk for malaria infection, the World Health Organization recommends measuring other APPs such as C-reactive protein (CRP) and a-1-acid-glycoprotein (AGP) in addition to ferritin to detect an APR.
It is imperative that iron status be accurately assessed so treatment can be provided to those who are deficient. A new study published in the American Journal of Clinical Nutrition explored how they could control for inflammation-related changes in ferritin when testing for iron deficiency in a population of individuals with high inflammation from malaria infections. Researchers asked whether other biomarkers of inflammation must be measured and what adjustments should be made to ferritin concentration cut-offs in these populations.
In this study, preschool children (PSC) and women of reproductive age (WRA) were assessed for ferritin concentrations, inflammation, and presence of malaria infection. Data were collected from the Biomarkers Reflecting the Inflammation and Nutritional Determinants of Anemia (BRINDA) project. Iron stores (ferritin concentrations) were estimated in inflammation and malaria settings by increasing the ferritin-concentration cut-off from <15ug/L to <30ug/L, excluding individuals with high CRP or AGP levels, or using manual correction approaches.
The study found that iron deficiency estimates increased as CRP and AGP levels decreased, indicating that as inflammation decreased, measuring ferritin concentration could more accurately predict iron status. When CRP and AGP levels were used to identify individuals with high inflammation, the number of detected cases of iron deficiency increased. However, the greatest increase in detection rate came from using an regression correction approach following ferritin measurements.
The results of this study support the use of manual correction approaches to identify iron deficiency in individuals from regions with high inflammation as it reflects the relationship between ferritin concentration and APPs. However, further research is needed to validate this approach and to provide more evidence to guide decisions on detecting iron deficiencies in high inflammation populations.
Written By: Neeti Vashi, BSc