ASSOCIATIONS BETWEEN PHYSICAL ACTIVITY AND RISK FACTORS FOR TYPE II DIABETES IN PREDIABETIC ADULTS
Isabel, Rukia   (Vanderbilt University)
Mentor: Buchowski, Maciej S. (Vanderbilt University)
Diabetes is a national healthcare crisis, and complications of diabetes are related to both macrovascular and microvascular complications. Prediabetes is when blood sugar and insulin resistance levels are higher than normal but not yet high enough to be considered type 2 diabetes. With the right interventions and lifestyle changes, individuals with prediabetes can avoid progression to diabetes. We hypothesized that higher levels of physical activity are associated with lower total and visceral fat mass, lower systolic blood pressure, and increased insulin sensitivity. To be included in the study, participants had to be 21- 50 years old, BMI = 30 kg/m2), have hemoglobin A1C from of 5.7 to 6.4, fasting glucose between 100 and 125 mg/dL, and Homeostatic Model Assessment of Insulin Resistance: (HOMA IR) = 2.5. Exclusion criteria included a diagnosis or history of diabetes, hypertension, HIV, renal disease, hearing loss, excess alcohol intake (4 drinks a day), use of organic nitrates or PDE5 inhibitors, known history of decreased cardiac function (arrhythmias, stroke, angina, myocardial infarction, seizures). Anthropometric measures were obtained using standard methods and body composition measured using Dual-Energy X-ray Absorptiometry (DXA). Total physical activity was measured using tri-axial accelerometers (ActiGraph- GT9X+) worn on a non-dominant wrist for 7 days 24 h/day. After assessing monitor wear/no-wear time, the outcomes of interest were total number of counts and time spent in sedentary, light, moderate and vigorous activity intensities. Clinical and biochemical cardiometabolic risk factors, blood pressure and heart rate, were obtained using a calibrated sphygmomanometer. Fasting glucose, insulin, lipid profile, high-sensitivity C-reactive protein, and BMP are analyzed using standard procedures. Insulin resistance was measured using a frequently sampled intravenous glucose tolerance test (fsIVGTT). The study found that participants with higher total amount of physical activity had an overall higher insulin sensitivity, lower blood pressure, lower fat mass as percentage of total body mass, and lower visceral adipose tissue. Total amount of physical activity showed small, but significant correlations with systolic blood pressure, visceral fat, total fat mass and insulin sensitivity. After normalizing for race, age, and gender, using multiple regression, these associations remained significant for insulin sensitivity, but not for total fat mass and visceral adipose tissue mass. Relatively homogenous (race, age, gender) but small sample size was the most likely factor affecting the association of amount of physical activity with risk factors for type 2 diabetes. We concluded that total amount of physical activity is associated with risk factors for type 2 diabetes in adults with prediabetes. Future plans include studies with higher sample size, conducting cross sectional and longitudinal studies in various populations with prediabetes, and exploring feasibility of physical activity measures as a risk marker(s) for type 2 diabetes and cardiovascular disease.