Changes in Glucose Homeostasis and Systemic Inflammation Following an 8-week Exercise Only and 8-week Exercise Plus Dietary Weight Management Intervention among Overweight and Obese African American Older Adults with Osteoarthritis
Background. Obesity is associated with impaired fasting blood glucose, insulin resistance (IR) and low-grade in- flammation, all of which are risk factors for chronic diseases including type 2 diabetes (T2D). Glucose metabolism and inflammation can be modified with lifestyle changes, although few studies have examined the impact of behav- ioral lifestyle interventions conducted in a “real world” community-based setting on these parameters in overweight and obese older African American (AA) adults with osteoarthritis (OA). The aim of this study was to examine the impact of an 8-week exercise only and 8- week exercise plus dietary weight management intervention on glucose me- tabolism and systemic inflammation in older overweight and obese AA adults with pre-existing lower extremity OA.
Methods. Participants were randomized to an 8-week exercise-only (n=59) or exercise plus dietary weight manage- ment (n=48) intervention. Baseline and post-intervention body measures (weight, BMI, and percent body fat) and fasting serum glucose, serum insulin, high sensitivity C-reactive protein and interleukin-6 were assessed. The homeo- static model assessment of insulin resistance (HOMA-IR) was also calculated. Demographic and health-related data were obtained via questionnaire at baseline. Generalized estimating equations to compare changes from baseline ad- justed for BMI and Spearman’s correlation examining the relationship between change in body measures and change in inflammation and glucose metabolism were also examined.
Results. The participants were predominately female (86%) with mean age of 67.1 (± 5.6) years and mean BMI of 34 kg/m2 (95% Confidence Interval: 31.9 – 36.1 kg/m2). Participants in the exercise plus dietary weight management group lost significantly more weight on average than those in the exercise-only group (-2.0 vs. -0.1 kg; p < 0.001). There was no significant between-groups change in markers of inflammation or glucose metabolism, although a clin- ically meaningful 5% (-5.1 mg/dl) decline in glucose from baseline was observed in the exercise plus dietary weight management group.
Conclusions. An 8-week exercise plus dietary weight management intervention has potential clinical relevance in regard to improving both body weight and glucose metabolism in a population at elevated risk for T2D and its related complications.
Acknowledgements. This work was supported by the National Institute on Aging at NIH (grant number: R01AG039374) and the American Cancer Society Illinois Division (grant number: 261775).