# 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.

## Key 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.