LETTERS TO THE EDITOR

Data with unexpected values should be checked

Dear Editor,

I would like to stress the quality of the article "Nutritional assessment of iron status and anemia in children under 5 years old at public daycare centers," by Vieira et al.¹ (Jornal de Pediatria, Vol. 83, No. 4, 2007), and also ask the authors if there might be a typing error in the values of free erythrocyte protoporphyrin (FEP) in Table 3: should not it be, for instance, 67 (61-74), 55 (53-57) and 50 (48-52)?  Even if they are geometric means (antilogarithm of arithmetic mean of original value logarithms), I cannot understand how transformed values were 6.7 (6.1-7.4), etc., as shown in Table 3 (compare with the value of 69.6% of children who had FEP levels higher than 40 µmol/mol heme, Table 1). Another possibility that I considered was that those values are actually arithmetic mean of original value natural logarithms (base e), but that is not included in the methodology, which makes this hypothesis less likely.

I would also like to confirm the values of serum ferritin, shown in Table 3, since the magnitude of such values is possible, although equally "weird," since they seem to be a little low in relation to the information in Table 1, which shows that 30.8% of the children had values lower than 12 ng/mL.

Thank you for being so kind to forward this request to the authors.

No conflicts of interest declared concerning the publication of this letter.

Marcos Borato Viana
Professor, Department of Pediatrics, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil

Authors' reply

Dear Editor,

With regard to the article,¹ we would like to inform that the comments made by Dr. Marcos Borato Viana are entirely pertinent, since the data presented concern the values of serum ferritin (SF) and free erythrocyte protoporphyrin (FEP) in base 10 antilogarithm, and not in natural logarithm, as recommended. In this sense, if possible, we request inclusion of the corrected values in Table 2 below. We also request publication of the correct information for the values of SF and FEP in Table 3. Coherently, in Methods, page 371, fifth paragraph, fourth line, (log10) should read (logn).

No conflicts of interest declared concerning the publication of this letter.

Ana Cláudia F. Vieira, Alcides S. Diniz, Poliana C. Cabral, Rejane S. Oliveira, Margarida M. F. Lola, Solange M. M. Silva, Patrick Kolsteren

Reference

1. Vieira AC, Diniz AS, Cabral PC, Oliveira RS, Lóla MM, Silva SM, et al. Nutritional assessment of iron status and anemia in children under 5 years old at public daycare centers. J Pediatr (Rio J). 2007;83(4):370-376.        [ Links ]