Abstract 235: Association Between Abnormal Ankle-Brachial Index and Accelerometer-Derived Sedentary and Exercise Time in the Asymptomatic General Population

Abstract

Objectives: Sedentary behavior is a distinct adverse health risk factor that is independent of physical activity. The association between sedentary behavior, exercise activity and ankle-brachial index (ABI) is not well understood. Methods: We analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004. Participants were included if they had ABI testing and at least one day of accelerometer data with exclusion of participants with self-reported anatomical or functional impairments to ambulation. Accelerometer counts reflect the intensity of activity in 1-minute intervals up to seven days for all participants. We used previously established exercise intensity-threshold criteria to quantify moderate-vigorous physical activity time. Sedentary time was defined as <100 counts/minute. We defined abnormal ABI as a value <1.0 (to include borderline values) in either foot. We performed multi-variable adjusted logistic regression analyses with sedentary time and exercise time as the independent variables and abnormal ABI as the dependent variable, adjusting for important risk factors and confounders. In a sensitivity analysis, we restricted the definition of abnormal ABI to <0.95. Results: We included 1,443 asymptomatic participants (mean age 61 years, 49% female, 55% current/prior smokers). The mean daily sedentary and exercise times in the study population were 454 ± 144 and 17.7 ± 20.3 minutes, respectively. 23.0% had an abnormal ABI (8.7% with ABI <0.9). In the final multivariable model, sedentary time was associated with increased odds of abnormal ABI (p=0.018) while exercise time was associated with reduced odds of abnormal ABI (p=0.003), independent of traditional risk factors and confounders (Figure, continuous variables per 1 standard deviation). Restricting the analysis to abnormal ABI<0.95, sedentary time and exercise time remained significant (p=0.024 and p=0.018, respectively). Conclusions: Sedentary time is associated with abnormal ABI values independent of exercise activity and other potential confounders in asymptomatic patients in the general population. Prospective studies are warranted to further evaluate the potential etiologic role of activity profiles on the development of peripheral arterial disease.