Background: Large artery stiffness, thought to be a marker of cardiovascular disease, is accelerated in persons with diabetes and hypertension. While reduced fatness and increased fitness are associated with lower BP, we tested the hypothesis that increased fatness and reduced fitness are each independently associated with greater aortic stiffness.
Methods: Sedentary subjects (M=60; F=29), mean (SD) age 57.1 (5.8) years, were examined at baseline as part of an exercise training study to reduce BP in persons with type 2 diabetes. Subjects were taking their usual medical therapy. For BP eligibility, subjects were required to have SBP between 120–159 and/or DBP between 80–99 mm Hg during 2 consecutive weekly visits. BP was the mean of the screening visits and a visit after qualification for the study. Aortic stiffness was assessed by carotid-to-femoral pulse wave velocity (PWV), using ultrasound probes simultaneously at each of these sites. General fatness was assessed by dual-energy x-ray absorptiometry (DEXA) and expressed as percent body fat. Abdominal fatness was assessed by magnetic resonance imaging at the level of the umbilicus and the areas for total, subcutaneous, and visceral fat were measured. Maximal oxygen uptake was obtained on a treadmill. The associations of PWV with BP, oxygen uptake, and abdominal fat were determined by stepwise regression analysis with adjustment for age and gender.
Results: PWV was 922.9 (300.0) msec, SBP was 126.9 (13.2) mm Hg, DBP was 71.8 (8.8) mm Hg, pulse pressure (PP) was 55.0 (10.4) mm Hg, percent body fat was 35.0 (6.5) %, and maximal oxygen uptake was 21.7 (5.0) ml/kg/min. In the final model, the variance in PWV was accounted for by increased PP, 8.9%; increased abdominal visceral fat accounted for an additional 6.2%; increased percent body fat, an additional 3%; and decreased maximal oxygen uptake, an additional 5.6%.
Conclusions: These data bring to light an independent relationship of aortic stiffness with increased fatness and reduced fitness. Though further work is needed to elucidate the mechanisms linking aortic stiffness, fatness, and fitness, these findings support the need for a therapeutic approach for reducing aortic stiffness that considers the potential benefits of weight reduction and exercise.
Relationship between maximal fat oxidation and oxygen uptake: comparison between type 2 diabetes patients and healthy sedentary subjects