Independent and joint associations of cardiorespiratory fitness and weight status with health-related quality of life among Brazilian adolescents

Purpose To investigate the independent and joint associations of cardiorespiratory fitness and body mass index (BMI) with five dimensions of Health-Related Quality of Life (HRQoL) in a cross-sectional sample of Brazilian adolescents. Methods 619 Brazilian schoolchildren answered a survey, BMI categories (healthy weight and overweight/obesity) were assessed by their weight and height, and they participated in a 20-m shuttle run test. HRQoL was measured using the KIDSCREEN-27 across five dimensions: Physical Well-Being, Psychological Well-Being, Autonomy and Parent Relation, Peers and Social Support, and School Environment. Sex, age, maternal education, physical activity level, and habitual sedentary behaviour were assessed and used as adjusting variables. Cardiorespiratory fitness was categorized in tertiles and independent and joint associations were tested using mixed-effects linear regressions. Results Higher levels of cardiorespiratory fitness were favourably associated with the physical well-being, psychological well-being, and peer and social support dimensions of HRQoL. Adolescents with overweight/obesity presented higher scores on peer and social support dimensions when compared to healthy-weight adolescents. Independent of the adolescents’ BMI categories, better cardiorespiratory fitness was positively associated with physical and psychological well-being when compared with the category of overweight/obesity and low cardiorespiratory fitness. In addition, adolescents with overweight/obesity combined with intermediate cardiorespiratory fitness or high cardiorespiratory fitness had higher scores on the peer and social support dimension. Conclusion Cardiorespiratory fitness is a strong correlate of HRQoL across most of the dimensions measured, while BMI was a correlate of one dimension of HRQoL. Future studies should evaluate these relationships prospectively and experimentally.