RELATIONSHIP BETWEEN INSULIN RESISTANCE, BODY COMPOSITION, AND PHYSICAL ACTIVITY IN OLDER ADULTS: 3911 Board #228 May 30 9:00 AM - 10:30 AM

There are 27 million adults in the U.S. with type II diabetes mellitus, a condition associated with significant morbidity and mortality. Existing therapies can be costly, have side effects and may not achieve adequate disease control. Therefore, it is useful to identify lifestyle factors such as physical activity (PA) that may mitigate insulin resistance. Key clinical indicators of insulin resistance include fasting blood glucose (FBG), hemoglobin A1c (HbA1c) percentage, and the homeostatic model assessment of insulin resistance (HOMA-IR). PURPOSE: To evaluate the relationships among insulin resistance indicators, body composition, and objective and subjective measures of habitual physical activity in older adults. METHODS: In 82 generally healthy nondiabetic adults (≥58 years, 23 m/59 f), body composition (bioelectrical impedance), fasting blood glucose (glucometer), serum insulin (enzyme-linked immunosorbent assay), HbA1c (HbA1c Analyzer), objective PA (7-day accelerometry), and subjective PA (Community Healthy Activities Model for Seniors (CHAMPS)) were measured. Controlling for age and body fat percentage, partial correlations between insulin resistance indicators and biometrics were determined (Significance was set as α < 0.05.) RESULTS: Mean values were (mean±sd): age (68.5±6.3 y), BMI (26.2±6.0 kg/m2), visceral fat (119.2±68.4 cm2), FBG (96.9±8.3 mg/dL), HOMA-IR (2.6±0.8), HbA1c (5.3±0.2%), and accelerometry (cts/min: 114.1±56.5; sedentary-to-moderate PA ratio: 12.8±6.1). FBG was significantly correlated with serum insulin (r = 0.26), visceral fat area (r = 0.40), cts/min (r = -0.29), and sedentary-to-moderate ratio (r = 0.24). HOMA-IR was significantly correlated with visceral fat (r = 0.41). No significant correlation was found between HbA1c and any measured variable. CONCLUSIONS: These preliminary data support previous findings that serum markers of insulin resistance are associated with physical activity and body composition. These findings suggest a potential role for using body composition and physical activity as clinical end points when managing patients with insulin resistance. Randomized controlled studies are needed to more rigorously assess the impact of physical activity on clinical indicators of diabetes mellitus in older adults.