RESUMO
BACKGROUND: The World Health Organization and Centers for Disease Control and Prevention recommend the inclusion of indicators of iron status and inflammation in surveys assessing iron deficiency and/or anemia. OBJECTIVE: We examined the associations between serum alpha(1)-acid glycoprotein (AGP), serum C-reactive protein (CRP), and urinary hepcidin and their relations with serum ferritin (SF), serum transferrin receptor (sTfR), and hemoglobin. DESIGN: At enrollment, the measurements were made in randomly selected 7-12-y-old anemic children with documented Schistosoma haematobium infection (n = 224 for AGP, CRP, SF, sTfR, and hemoglobin; n = 61 for urinary hepcidin). RESULTS: The correlation between the conventional markers of inflammation, AGP and CRP, was positive (r = 0.40, P < 0.01), and the correlation between the unambiguous markers of iron nutrition, hemoglobin and s-TfR, was negative (r = -0.36, P < 0.01). None of the correlations (r < 0.08) between the above markers was statistically significant. Urinary hepcidin correlated positively with the 2 measured indicators of inflammation (r > or = 0.42, P < 0.01) but not with the 2 indicators of iron nutrition (r < 0.07). SF correlated positively with the 2 measured inflammation markers (r > or = 0.25, P < 0.01) and the 2 iron-nutrition indicators (r > 0.26, P < 0.01). Urinary hepcidin correlated positively with SF (r = 0.39, P < 0.01). Regression analyses suggested that CRP and AGP were significant predictors of SF (P < 0.001); however, CRP (R(2) = 0.38) explained more of SF's variance than did AGP (R(2) = 0.17). CONCLUSIONS: Correlations between AGP, CRP, urinary hepcidin, and SF were statistically significant. CRP values explained SF's variance better than did the other markers of inflammation studied. We therefore recommend the measurement of both AGP and CRP in population surveys that include an assessment of iron deficiency in developing countries.
