Association of Objectively Measured Sedentary Behavior with Obesity in Adults

Background: Obesity has been a significant public health concern among US adults. Recently, a great attention has been given to the sedentary behavior (SB) in relation to obesity; however, controversial results have been reported due to the use of less accurate measures of SB and obesity in adults.

Purpose: The aim of the present study was to investigate the association between accelerometer-derived SB time and obesity measured by Dual-energy X-ray absorptiometry (DXA) among US national representative sample of adults.

Methods: Data from the 2003-2004 National Health and Nutrition Examination Survey were analyzed for this study. A total of 2577 adults (≥20 years, male = 1331) were included in this analysis. SB time was defined as 10 or more consecutive minutes with <100 counts per minute (cpm), with allowance for interruptions of 1 or 2 minutes with ≥100 cpm. SB time was categorized into quartiles. Obesity was classified by body fat percentage (≥ 25% for men, ≥ 30% for female). SAS v9.3 SURVEYREG and SURVEYLOGISTIC procedures were applied to examine the association between SB and obesity after controlling for moderate-to-vigorous activity (MVPA), age, gender, race/ethnicity, income, education level, and energy intakes.

Results: The average sedentary time and body fat percentage were 461.87 minutes (95% CI: 452.80-470.93) and 34.02% (95% CI: 33.46-34.58), respectively. Increase in SB time was significantly related to an increase in body fat percentage when adjusted for covariates (p< .01). The adjusted odds ratios were statistically significant between SB time and obesity for Q2 vs. Q1 (OR=1.37, 95% CI: 1.03-1.84), Q3 vs.Q1 (OR=1.57, 95% CI: 1.18-2.10), and Q4 vs. Q1 SB (OR=1.39, 95% CI: 1.04-1.86).

Conclusion: The results of the current study provide further evidence that prolonged SB associates significantly with obesity, independent of MVPA. This finding suggests that avoiding prolonged SB may be beneficial for lowering the risk of obesity in US adults.