Abstracts: American College of Sports Medicine Conference on Integrative Physiology of Exercise: SATURDAY, SEPTEMBER 30, 2006: POSTER SESSION 3: Metabolic
Cardiorespiratory fitness and obesity have been associated with serum C-reactive protein (CRP); however, the relative contribution of fitness and fatness to CRP is not clearly defined. Moreover, central adiposity and reductions in appendicular lean mass (aLM) have been linked to elevated levels of CRP in the elderly.
The primary purpose of this study was to determine the independent relationships between aerobic fitness, fatness, central adiposity and CRP. A secondary aim was to evaluate the relation between aLM and CRP.
Healthy sedentary adults (N= 85, M, n=32, F, n=53; 70.4 ± 5.2 y) who were free from corticosteroid use, inflammatory disease, recent illness and smoking were assessed for aerobic fitness (expressed as relative to body mass or fat-free mass) via a maximal oxygen consumption treadmill test, body composition via dual energy X-ray absorptiometry (DXA) and serum hs-CRP via ELISA. Relative aLM was calculated using a sarcopenia index (SI= aLM/ht2).
On average (M ± SD), subjects were overweight (BMI= 28.2 ± 4.9 kg/m2), low fit (19.3 ± 4.1 mL·kgBM·min−1 and 30.1 ± 5.0 mL·kgFFM·min−1), high risk for inflammation (CRP = 3.5 ± 2.9 mg/L) and low risk for sarcopenia (SI= 7.7 ± 1.5 kg/m2). Whole body fatness, expressed as total fat mass or %Fat, trunk fat and fitness were all related to CRP (all p < 0.01). Using stepwise linear regression, controlling for age and sex, only trunk fat and fitness, expressed relative to FFM, were independent predictors of CRP in the model (R2= 20.3%) explaining 13.6% (p = 0.002) and 6.6% (p = 0.011) respectively, whereas total fat mass (p = 0.48) or %Fat (p = 0.58) were not predictors. SI was not correlated with CRP (r = 0.17, p = 0.13), which held consistent when controlling for age, gender and %Fat (r = 0.10, p = 0.36).
Central adiposity and fitness are independent predictors of CRP. Importantly, central adiposity was associated with CRP independently of total adiposity. The lack of an independent relationship between SI and CRP is likely impacted by the robust sample of healthy elderly individuals who were not high risk for sarcopenia or sarcopenic obesity. These findings support the measure of central adiposity to assess risk of inflammation.
Supported by NIH grant # AG-18861 (PI: J.A. Woods)