Adjusting iron and vitamin A status in settings of inflammation: a sensitivity analysis of the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) approach

• Published in: The American journal of clinical nutrition 2020-08, Vol.112 (Suppl 1), p.458S-467S
• Main Authors: Namaste, Sorrel ML, Ou, Jiangda, Williams, Anne M, Young, Melissa F, Yu, Emma X, Suchdev, Parminder S
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anemia; Anemia, Iron-Deficiency - blood; Anemia, Iron-Deficiency - diagnosis; Biomarkers; Biomarkers - blood; C-reactive protein; C-Reactive Protein - metabolism; Child, Preschool; Children; Erythropoiesis; Etiology; Female; Ferritin; Ferritins - blood; Glycoproteins; Heterogeneity; Humans; Infant; Inflammation; Inflammation - blood; Inflammation - complications; Iron; Iron - blood; Iron deficiency; Male; meta-analysis; micronutrient; Nutrient deficiency; Nutrition Assessment; nutritional assessment; Nutritional Status; Orosomucoid - metabolism; Polls & surveys; Proteins; Public health; Receptors, Transferrin - blood; Regression analysis; Regression coefficients; Reproducibility of Results; Retinene; Retinol-binding protein; Retinol-Binding Proteins - metabolism; Sensitivity analysis; Statistical analysis; Supplements and Symposia; Transferrin; Transferrins; Vitamin A; Vitamin A - blood; Vitamin A Deficiency - blood; Vitamin A Deficiency - diagnosis; Young Adult
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/nqaa141

Accurate assessment of iron and vitamin A status is needed to inform public health decisions, but most population-level iron and vitamin A biomarkers are independently influenced by inflammation. We aimed to assess the reproducibility of the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) regression approach to adjust iron [ferritin, soluble transferrin receptor (sTfR)] and vitamin A [retinol-binding protein (RBP), retinol] biomarkers for inflammation (α-1-acid glycoprotein and C-reactive protein). We conducted a sensitivity analysis comparing unadjusted and adjusted estimates of iron and vitamin A deficiency using the internal-survey regression approach from BRINDA phase 1 (16 surveys in children, 10 surveys in women) and 13 additional surveys for children and women (BRINDA phase 2). The relations between inflammation and iron or vitamin A biomarkers were statistically significant except for vitamin A biomarkers in women. Heterogeneity of the regression coefficients across surveys was high. Among children, internal-survey adjustments increased the estimated prevalence of depleted iron stores (ferritin 8.3 mg/L) decreased by a median of 15 pp (15 pp and 20 pp in BRINDA phase 1 and phase 2, respectively). Vitamin A deficiency (RBP