30th Apr 2024

Introduction: Adherence to the 24-hour movement behaviors (24-HMB) guidelines has been positively associated with health indicators in adolescents. However, evidence regarding changes in the proportion of adolescents meeting these guidelines over time is scarce. This study aimed to determine changes in the proportion of adherence with 24-HMB recommendations during adolescence. Methods: Prospective study (with mean follow-up period of 3.2 years) comprising 117 adolescents (53.8% girls) from public school in the southern region of Brazil. Physical activity (PA) was objectively measured, while sedentary behavior (SB) and sleep were estimated using a self-administered instrument. The 24-HMB were dichotomized in adherence or non-adherence, according to international recommendations: i) moderate to vigorous physical activity ≥60 min/day; ii) sedentary behavior ≤2 hours/day of recreational screen time (TV); and iii) sleep = 8 to 10 hours/day), and then classified into three categories according to the combination of recommendations’ adherence: I) minimal adherence (only one behavior); II) partial adherence (two behaviors); III) total adherence (all three behaviors). The McNemar test was used to analyze whether adherence to the recommendations varied between the two time points. Results: The proportion of adolescents who met the recommendations at baseline and follow-up was 23.1% vs 35.1% (minimal adherence), 49.0% vs 52.1% (partial adherence), and 27.9% vs 12.8% (total adherence), respectively. Total adherence to the recommendations was higher at baseline compared to follow-up (P=0.009). No significant changes were observed between minimal and partial adherence over time. When analyzing behaviors individually, a significant reduction in adherence to the PA recommendations from baseline to follow-up was observed (70.4% vs. 39.9%, P<0.001). Conclusion: The proportion of total adherence to the 24-HMB guidelines in Brazilian adolescents is low and appears to decrease throughout adolescence.