Research, policy, and programmatic considerations from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project

The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project sought to inform the interpretation of iron and vitamin A biomarkers (ferritin, serum transferrin receptor, and retinol binding protein) in settings of prevalent inflammation as well as the prevention of and control strategies to address anemia. Our purpose is to comment on the contributions of the BRINDA to advance global knowledge with regard to iron and vitamin A status assessment in women and preschool children and to analyze the findings in terms of their rigor and usefulness for global nutrition research and programs. BRINDA investigators found that the acute-phase response is so prevalent that it must be assessed in surveys of iron and vitamin A status for valid interpretation of micronutrient biomarkers. Furthermore, they found that C-reactive protein and α-1-acid glycoprotein provide important and different information about these responses and that common survey variables cannot replace the information they provide. Developing a method for adjusting micronutrient biomarkers for the independent influence of inflammation is challenging and complex, and BRINDA has brought greater clarity to this challenge through the use of large and diverse data sets. When comparing approaches, the regression methods appear to perform best when sample sizes are sufficient and adequate statistical capacity is available. Further correction for malaria does not appear to materially alter regression-adjusted prevalence estimates. We suggest that researchers present both adjusted and unadjusted values for the micronutrient biomarkers. BRINDA findings confirm that iron deficiency is a common and consistent risk factor for anemia globally and that anemia control must combine iron interventions with control of infection and inflammation. Anemia control strategies must be informed by local data. By applying the knowledge in these studies, researchers, program planners, and evaluators working in populations with prevalent inflammation can use and interpret biomarkers with more confidence, tempered with necessary caution.