Detection of Anemia in Schoolchildren Aged 6–18 Years With Hematocrit Percentile Charts and the Impact of Economic Status in Southern Brazil

TL;DR

This study creates hematocrit percentile charts for schoolchildren in Brazil and finds that anemia is more common in lower-income boys and less common in higher-income girls.

Contribution

The novel contribution is generating sex-specific hematocrit percentile charts and analyzing anemia prevalence linked to socioeconomic status in southern Brazil.

Findings

Anemia prevalence was higher in lower-income boys compared to non-anemic boys.

Higher-income girls showed a lower prevalence of anemia compared to non-anemic girls.

Percentile charts revealed socioeconomic disparities in hematocrit levels among schoolchildren.

Abstract

To generate hematocrit percentile charts for schoolchildren aged 6–18 years and determine the prevalence of anemia by socioeconomic status class in southern Brazil.

This is a cross‐sectional study utilizing data collected between 2014 and 2017 from southern Brazil. The study's sample consists of 4802 schoolchildren, aged 6 to 18 years. The percentile charts for sex‐specific hematocrit were developed using the LMS (Lambda‐Mu‐Sigma) method. The simplified economic classification, based on ABEP criteria, was used to group individuals into A + B (high), C (middle), and D + E (low) income classes. Anemia was defined as hematocrit z‐score ≤ −1.96 for age and sex.

Among boys, 58 (2.86%) were anemic, 1955 (94.81%) had normal hematocrit levels, and 48 (2.33%) had high hematocrit. Girls showed a similar pattern, with 73 (2.73%) anemic, 2534 (94.90%) with normal hematocrit, and 63 (2.36%) with high hematocrit. For girls, a higher prevalence of non‐anemic hematocrit was observed in class A (39.33%) compared to anemic children (23.28%), with significant standardized residuals. For boys, significant residuals were observed for a higher prevalence of anemic children in the lower socioeconomic class DE (13.79%) compared to non‐anemic children (5.18%), and a higher prevalence of non‐anemic children in the upper socioeconomic class A (42.63%) compared to anemic children (22.41%).

The percentile charts generated from hematocrit levels enabled the comparison of anemia prevalence across socioeconomic status classes. A higher prevalence of anemia was found among boys in lower socioeconomic classes, while girls in higher socioeconomic classes showed a lower prevalence of anemia.

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