Aerobic capacity of preterm children with very low birth weight at school age and its associated factors

Abstract

Introduction: Respiratory morbidities of preterm infants can cause significant ventilatory impairment thus compromising the aerobic capacity in childhood and adolescence. Therefore, the present study was conducted to evaluate the aerobic capacity in school age preterm children with VLBW and its associated factors. Methods: A cross-sectional study was conducted among preterm born with VLBW and term children, both aged 6–9 years. An individualized symptom-limited treadmill testing protocol performed aerobic capacity. Measured variables: oxygen pulse (PuO2), percentage of maximum heart rate for age (%HR max), tidal volume/inspiratory capacity ratio (TV/IC), oxygen consumption (VO2) peak, and the ratio of the anaerobic threshold of gas exchange to the predicted percentage of maximum VO2 (VO2@LA/%VO2 max.pred.) were compared between groups. Univariate and multiple linear regression analyses were used to determine the factors associated with aerobic capacity. Results: Thirty-four preterm and 32 term children were included. SimilarVO2 peak and the other variables were observed. The development of bronchopulmonary dysplasia (BPD) and being obese/overweight was positively associated with %HR max. The Z-score for height/age and birth weight <1000 g was positively associated with PuO2 and peak VO2, and negatively associated with overweight/obesity and female sex. Conclusions: Aerobic capacity was similar in both groups. Sex, development of BPD, birth weight <1000 g and factors related to body growth, such as Z-score for height/age and overweight/obesity, were associated with aerobic capacity in preterm children with VLBW.