Body Mass Index and Physical Inactivity: 2013 BRFSS.

<bold>Objectives: </bold>Examine the odds of adults reporting physical inactivity (PI) across six body mass index (BMI) categories.<bold>Methods: </bold>We used data from the 2013 Behavioral Risk Factor Surveillance System. Six BMI categories were used.<bold>Results: </bold>The odds of reporting PI in underweight men and men in the class I, II, and III obesity categories were 1.65 (95% confidence interval [CI] 1.35-2.02), 1.30 (95% CI 1.21-1.39), 1.73 (95% CI 1.58-1.90), and 2.44 (95% CI 2.17-2.75), respectively, compared with men of desirable weight (odds ratio [OR] 1.00, 18.5-24.9 kg/m2; referent, OR 1.00). The odds of reporting PI in underweight men were similar to class II and class III obese men. The odds of reporting PI in underweight women, overweight women, and women in the class I, II, and III obesity categories were 1.57 (95% CI 1.36-1.81), 1.20 (95% CI 1.14-1.27), 1.65 (95% CI 1.56-1.75), 2.23 (95% CI 2.07-2.40), and 2.89 (95% CI 2.66-3.15), respectively, compared with women of desirable weight (≥18.5-24.9 kg/m2; referent, OR 1.00). The odds of reporting PI were similar in underweight and class I obese women. Women were found to have greater odds than men of reporting PI in four of the five nondesirable BMI categories (P < 0.05).<bold>Conclusions: </bold>The within- and between-sex differences in the odds of reporting PI vary significantly by BMI category. Future research needs to include the underweight BMI category when investigating PI and sedentary time because of the potential clinical relevance. [ABSTRACT FROM AUTHOR]