Fitness Modifies the Association Between C-Reactive Protein and the Metabolic Syndrome in Racially Diverse Women

Abstract

0576 C-reactive protein (CRP) is related to metabolic syndrome (MS) prevalence and incidence. Both factors are associated with an increased risk of coronary events. Cardiorespiratory fitness (fitness) is inversely related to both CRP and MS, however, the extent that fitness modifies the association between CRP and MS is unknown. PURPOSE: To examine cross-sectional associations between CRP, MS and fitness among women in the Cross-Cultural Activity Participation Study. METHODS: Study participants included 44 African Americans (AA, mean age = 56 yr, mean BMI = 30 kg/m2), 45 Native Americans (NA, 50 yr, 29 kg/m2), and 46 Caucasians (CA, 54 yr, 25 kg/m2). Plasma CRP was measured with the Dade-Behring high-sensitivity immunoassay. High CRP was defined as >0.20 mg/dL. MS was defined according to NCEP-ATP III criteria. Insulin resistance was computed with the HOMA-IR method. Fitness was defined as age-adjusted peak METs estimated from a maximal treadmill exercise test. High fitness was defined as > 8.5 METs. RESULTS: The prevalence of MS, high CRP, and high fitness varied (P<0.05) by race. Race-adjusted geometric mean CRP values were directly associated (P<0.05) with the presence of each MS component, elevate plasma insulin, elevated HOMA-IR, and low fitness. CRP values increased with increasing number of co-existing MS components (P<0.0001). Fit women (> 8.5 METs, n = 69) had lower (P<0.0005) prevalence of high CRP (31% vs. 62%) and MS (10% vs. 35%) compared with unfit women (<8.5 METs, n = 68). After adjusting for age and race, the presence of MS was 3.6 fold higher (95% CI = 1.5 – 8.4, P = 0.003) among women with high versus low CRP. The association between CRP and MS remained significant after adjusting for hormone replacement, BMI, and HOMAIR. However, the association between CRP and MS was no longer significant (OR = 1.3, 95% CI = 0.9 – 5.9, P = 0.59) after adjustment for fitness. CONCLUSION: CRP is a significant predictor of MS among racially diverse women even after adjustment for confounding factors including hormone use and insulin resistance. Higher fitness favorably modifies the association between CRP and MS. An active and fit lifestyle should be seen as an important preventive measure against vascular inflammation and MS development. Supported by NIH WHI-SIP 22W-U48/CCU409664