Moderating Effect of Physical Activity and Body Mass Index on the Relationship Between Sedentary Behavior and...

We examined the moderating effect of moderate to vigorous physical activity (MVPA) and body mass index (BMI) on the association between sedentary behavior (SB) and cardiometabolic markers (CMM) in adolescents.

In this 3-year longitudinal study (2014, 2015, and 2017), we collected and analyzed data from 136 adolescents (10-13 y) from João Pessoa, Paraíba, Brazil. We collected SB data using an ActiGraph GT3X+ accelerometer and calculated total sedentary time (in hours per day), also classifying participants into 2 exposure patterns: "Low SB" (≤8 h/d) and "High SB" (>8 h/d). We evaluated CMM including: glucose, total cholesterol (TC), triglycerides (TG), high-density (HDL-C) and low-density lipoprotein cholesterol non-HDL-C, TC/HDL-C, TG/HDL-C, BMI, waist circumference, and systolic and diastolic blood pressure. We applied Generalized Estimating Equations to test whether time spent in MVPA and BMI moderated associations between SB and CMM.

The Generalized Estimating Equation identified significant interactions between SB and MVPA, as well as between SB and BMI, for several CMM (P < .05). Among adolescents with low SB exposure (≤8 h/d), those who accumulated more MVPA (>50 min/d) showed more favorable lipid profiles, including TC, LDL-C, non-HDL-C, and TC/HDL-C ratio. The combination of high SB exposure (>8 h/d) and excess weight was associated with less favorable TG, TC/HDL-C, TG/HDL-C, HDL-C, waist circumference, and systolic blood pressure values. Even under low SB exposure, excess weight corresponded to less favorable TC/HDL-C, TG/HDL-C, HDL-C, and waist circumference levels.

MVPA moderated associations with CMM only at low sedentary exposure, whereas excess body weight amplified adverse associations across multiple cardiometabolic outcomes during adolescence.