Physical Activity and Sedentary Behavior in Populations with Impaired Glucose Metabolism and Type 2 Diabetes Mellitus

INTRODUCTION: The high physical and economic burden of type 2 diabetes mellitus is an important public health concern. The impact of various intensities of physical activity (PA) and sedentary behavior on the development of type 2 diabetes is not well understood. Additionally, more insight into how measurement methodologies for PA and sedentary behavior affect the values of activity-related outcome variables is needed. METHODS: PA and sedentary behavior levels were assessed as part of a multi-center clinic trial of youth with type 2 diabetes from 15 U.S. centers; the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study. Agreement between the results of a subjective and objective measure of PA and sedentary behavior were examined. Also, accelerometer processing algorithms were examined, using data on adults in the National Health Examination and Nutrition Survey (NHANES) 2005-06, to determine how changing the definition of accelerometer non-wear impacts on important PA outcome variables. PA and sedentary behavior levels from accelerometers were also described in 1609 adults with impaired glucose tolerance or type 2 diabetes, in the multi-center Diabetes Prevention Program Outcomes Study (DPPOS). These results were compared to similarly assessed activity data for a nationally representative sample of adults. RESULTS: In TODAY youth, agreement was low between the Three Day Physical Activity Recall (3DPAR) questionnaire and accelerometer results; suggesting that the 3DPAR may not provide an accurate measure of time spent in PA or sedentary behavior in overweight/obese youth with type 2 diabetes. For NHANES adults, changing the definition of accelerometer non-wear time resulted in clinically significant differences in estimates of time spent sedentary, especially in older individuals. Compared to a nationally representative sample of adults, the DPPOS participants performed more moderate-vigorous intensity (MV) PA, but not more light intensity PA. These results likely reflect the effects of a successful lifestyle intervention on MVPA. PUBLIC HEALTH SIGNIFICANCE: The current effort advances the understanding of PA and sedentary behavior assessment methods in populations with impaired glucose tolerance and type 2 diabetes and provides estimates for the average amount of time individuals in these populations spend physically active and sedentary