title: Estimation of the effect of the acute phase response on indicators of micronutrient status in Indonesian infants.
abstract: Many indicators of micronutrient status change during infection because of the acute phase response. In this study, relationships between the acute phase response, assessed by measuring concentrations of C-reactive protein (CRP), alpha(1)-antichymotrypsin (ACT) and alpha(1)-acid glycoprotein (AGP), and indicators of micronutrient status were analyzed in 418 infants who completed a 6-mo randomized, double-blind, placebo-controlled, supplementation trial with iron, zinc and/or beta-carotene. The acute phase response, defined by raised CRP (plasma concentration >10 mg/L), raised AGP (>1.2 g/L), or both raised CRP and AGP, significantly affected indicators of iron, vitamin A and zinc status, independently of the effects of supplementation. Plasma ferritin concentrations were higher by 15.7 (raised AGP) to 21.2 (raised CRP and AGP) micro g/L in infants with elevated acute phase proteins compared with infants without acute phase response (P < 0.001). In contrast, plasma concentrations of retinol were lower by 0.07 (P < 0.05, raised AGP) to 0.12 (P < 0.01, raised CRP) micro mol/L, and of zinc lower by 1.49 (P < 0.01, raised AGP) to 1.89 (P < 0.05, raised CRP and AGP) micro mol/L. Hemoglobin concentrations and the modified relative dose response were not affected. Consequently, the prevalence of iron deficiency anemia was underestimated in infants with raised acute phase proteins by >15%, whereas the prevalence of vitamin A deficiency was overestimated by >16% compared with infants without acute phase response. Hence, using indicators of micronutrient status without considering the effects of the acute phase response results in a distorted estimate of micronutrient deficiencies, whose extent depends on the prevalence of infection in the population.
mesh_terms: D000209:Acute-Phase Proteins / Q000032:analysis*; D000210:Acute-Phase Reaction / Q000097:blood*; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005293:Ferritins / Q000097:blood; D006801:Humans; D007223:Infant; D019266:Iron, Dietary / Q000008:administration & dosage; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage* / Q000097:blood*; D009752:Nutritional Status; D010919:Placebos; D015995:Prevalence; D014802:Vitamin A Deficiency / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D015032:Zinc / Q000008:administration & dosage / Q000097:blood; D000514:alpha 1-Antichymotrypsin / Q000097:blood; D019207:beta Carotene / Q000008:administration & dosage / Q000097:blood
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D019266:Iron, Dietary; D018977:Micronutrients; D010919:Placebos; D000514:alpha 1-Antichymotrypsin; D019207:beta Carotene; D002097:C-Reactive Protein; D005293:Ferritins; D015032:Zinc