Curvas de crescimento em escolares no período da infância até a adolescência.

Abstract

patterns of children, encompassing everything from height to weight, from birth to puberty. Growth charts are used to detect, monitor, and track the health of schoolchildren, being especially effective in identifying nutritional disorders. General objective: To develop growth charts for a sample of schoolchildren during childhood, puberty, and adolescence. Article 1 - Objective: To create growth charts for BMI and height of children and adolescents in urban and rural areas in southern Brazil. Keywords: Growth curve; LMS method; Puberty; Growth spurt; Urban-rural zone. Method: This is a cross-sectional study including 4,802 schoolchildren of both sexes, aged 7 to 18 years, in a city in southern Brazil during the years 2014 to 2017. Normative growth charts for height and BMI were constructed using the LMS method. The charts were created separately for sex and area of residence (urban and rural). The growth charts were compared with the standard charts proposed by WHO in 2007. Results: The height growth charts displayed a pattern similar to the 2007 WHO growth chart. The notable exception was rural boys, who showed a continuous growth rate until age 18, unlike urban boys and the WHO chart, which showed stabilization from age 15. BMI exhibited a linear growth trajectory for both sexes and areas, deviating from the pattern established by the 2007 WHO charts. The maximum growth peak was for urban boys at age 13, with 6.2 cm/year. On the other hand, rural boys showed a constant growth rate of 5.8 cm/year. Urban girls reached a growth peak of 6.2 cm/year at age 10, while rural girls had a peak of 5.9 cm/year at 10.2 years. Final considerations: No significant differences were found in pubertal timing between rural and urban areas. The findings of this study highlight the need to develop growth charts specific to each population, each with its own set of cut-off points that define the boundaries of normality. Article 2 - Objective: To generate growth charts for hematocrit levels in children and adolescents aged 6 to 18 years and to determine the prevalence of anemia by socioeconomic class. Keywords: Growth charts; LMS method; Hematocrit; Anemia. Method: This is a cross-sectional study using data collected between 2014 and 2017 in southern Brazil. The study sample consisted of 4,802 schoolchildren aged 6 to 18 years. Hematocrit growth charts specific to sex were developed using the LMS (Lambda-Mu-Sigma) method. The simplified classification into three socioeconomic status classes was generated according to the criteria proposed by the Brazilian Association of Research Companies (ABEP), classified as A + B, C, and D + E. Results: Among boys, 58 (2.86%) were anemic, 1,955 (94.81%) had normal hematocrit levels, and 48 (2.33%) had elevated hematocrit. The girls showed a similar pattern, with 73 (2.73%) anemic, 2,534 (94.90%) with normal hematocrit, and 63 (2.36%) with elevated 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 higher socioeconomic class A (42.63%) compared to anemic children (22.41%). Final considerations: Hematocrit growth charts are therefore clinically useful for screening anemia in children and adolescents, as hematocrit is a quick and low-cost test. These charts allowed the comparison of anemia prevalence across socioeconomic classes. A higher prevalence of anemia was found among boys from lower socioeconomic classes, while girls from higher socioeconomic classes showed a lower prevalence of anemia. Final considerations of the dissertation: The analysis of the height and BMI growth charts did not identify significant differences in pubertal timing between rural and urban areas, with the onset of puberty occurring similarly for both sexes between the ages of 10 and 14. Hematocrit growth charts are therefore clinically useful for screening anemia in children and adolescents, as hematocrit is a quick and low-cost test. New data collections need to be carried out to update the growth charts, and the importance of developing growth charts for different regions of the country is also highlighted.