Combined associations of sitting time and physical activity with obesity in young adults

<b>Background</b>: <br />We investigated associations of total sedentary behavior (SB) and objectively-measured and self-reported physical activity (PA) with obesity.<br /> <br /><b>Methods</b>: <br />Data from 1662 adults (26–36 years) included daily steps, self-reported PA, sitting, and waist circumference. SB and PA were dichotomized at the median, then 2 variables created (SB/self-reported PA; SB/objectively-measured PA) each with 4 categories: low SB/high PA (reference group), high SB/high PA, low SB/low PA, high SB/low PA. <br /><br /><b>Results</b>: <br />Overall, high SB/low PA was associated with 95 –168% increased obesity odds. Associations were stronger and more consistent for steps than self-reported PA for men (OR 2.68, 95% CI 1.36–5.32 and OR 1.95, 95% CI 1.01–3.79, respectively) and women (OR 2.66, 95% CI 1.58–4.49 and OR 2.00, 95% CI 1.21–3.31, respectively). Among men, obesity was higher when daily steps were low, irrespective of sitting (low SB/low steps OR 2.07, 95% CI 1.03– 4.17; high SB/low steps OR 2.68, 95% CI 1.36–5.32). <br /><br /><b>Conclusions</b>: <br />High sitting and low activity increased obesity odds among adults. Irrespective of sitting, men with low step counts had increased odds of obesity. The findings highlight the importance of engaging in physical activity and limiting sitting.