Association between elevated liver enzymes and C-reactive protein: possible hepatic contribution to systemic inflammation in the metabolic syndrome.

OBJECTIVE: The objective of this study was to test whether the frequent association between liver enzyme elevations and various components of the metabolic syndrome is associated with higher C-reactive protein (CRP) levels. METHODS AND RESULTS: Alanine aminotransferase (ALT), alkaline phosphatase (Alk-P), and high-sensitivity CRP were measured in 1740 subjects. Adjusted geometric mean CRP was calculated for subjects with normal and elevated ALT and for subjects with normal and elevated Alk-P, adjusting for age, sex, smoking, physical activity, body mass index, fasting glucose, triglycerides, the presence of hypertension and low HDL cholesterol, and use of aspirin or hormone replacement therapy. Adjusted CRP levels were higher in subjects with elevated ALT (2.21 versus 1.94 mg/L, P=0.028) or elevated Alk-P (2.58 versus 1.66 mg/L, P<0.0001). Logistic regression showed that compared with subjects with normal liver function tests, the adjusted odds for high-risk CRP (>3 mg/L) were significantly higher in subjects with elevated ALT (OR, 1.5; 95% CI, 1.2 to 1.9, P=0.002) or elevated Alk-P (OR, 2.1; 95% CI, 1.7 to 2.6, P<0.0001). CONCLUSIONS: Elevations of liver enzymes are associated with higher CRP concentrations. Hepatic inflammation secondary to liver steatosis is a potential contributor to the low-grade inflammation associated with the metabolic syndrome.

The association between cardiorespiratory fitness and C-reactive protein in subjects with the metabolic syndrome.

OBJECTIVES: We sought to study relationship between cardiorespiratory fitness and C-reactive protein (CRP) in subjects with the metabolic syndrome. BACKGROUND: Recent studies have shown an association between the metabolic syndrome and chronic subclinical inflammation, as determined by elevated CRP. Cardiorespiratory fitness is associated with a lower risk of diabetes and improved insulin resistance. METHODS: Physical fitness was assessed in 1,640 subjects using the Bruce treadmill protocol and expressed as maximal metabolic equivalents. The level of CRP was measured using a high-sensitivity assay. RESULTS: Geometric mean CRP was calculated across quartiles of fitness after adjustment for age, gender, smoking, use of medications, and coronary disease. A strong inverse trend toward decreasing CRP levels with increasing fitness quartiles was present in subjects without metabolic abnormalities, subjects with one or two metabolic abnormalities, and subjects with the metabolic syndrome (all p

C-Reactive protein is inversely related to physical fitness in middle-aged subjects.

INTRODUCTION: Physical fitness has a protective effect with regard to the risk of developing coronary disease or diabetes. C-reactive protein (CRP) levels are directly related to increased risk of coronary disease and diabetes. However, data on the association between physical fitness and CRP are sparse. METHODS: Physical fitness was assessed in a population-based cross-sectional study (n = 892; age 50 +/- 9 years) using the Bruce treadmill protocol. CRP was measured using a high-sensitivity assay. RESULTS: Geometric mean CRP levels were calculated across quartiles of physical fitness after adjustment for age, gender, body mass index, smoking habit, presence of diabetes and hypertension, HDL cholesterol and triglyceride levels, and use of hormone replacement therapy, statins, and aspirin. CRP levels decreased with increasing quartiles of fitness (P for trend <0.0001). When used as a continuous variable in a stepwise linear regression model, the geometric mean of CRP decreased by 0.061 mg/L (95% confidence interval (CI) 0.034-0.089 mg/L) for each 1 unit increase in metabolic equivalents (METs). Multivariate logistic regression models showed that compared to subjects in the lowest fitness quintile, subjects in the highest fitness quintile had significantly lower adjusted odds of having a high-risk (>3 mg/L) CRP level (OR 0.53; 95% CI 0.39-0.71, P = 0.007). CONCLUSION: CRP concentration decreases continuously with increasing levels of physical fitness. The health-related salutary effects of physical fitness may be mediated, in part, through an antiinflammatory mechanism.

Inverse association between pulmonary function and C-reactive protein in apparently healthy subjects.

RATIONALE: Increased levels of systemic markers of inflammation have been reported in patients with impaired lung function due to obstructive or restrictive lung disease. OBJECTIVE: We tested the hypothesis that a decline in lung function within the normal range may be associated with a systemic subclinical inflammation. METHODS: Pulmonary function tests, cardiorespiratory fitness, components of the metabolic syndrome, and high-sensitivity C-reactive protein (CRP) were determined in 1,131 subjects without known pulmonary disease. MEASUREMENTS AND MAIN RESULTS: Ninety-six of the study participants (8.5%) had FEV(1) of less than 80% of predicted values. There was a strong inverse association between CRP levels and quartiles of FEV(1). The median CRP levels in nonsmoking participants were 2.5, 1.8, 1.7, and 1.3 mg/L in the first, second, third, and forth FEV(1) quartiles, respectively (p < 0.0001). A similar inverse association was present in smoking subjects (median CRP levels were 3.8, 2.3, 2.0, and 1.9 mg/L in the first, second, third, and fourth FEV(1) quartiles, respectively; p < 0.0001). These associations remained highly significant after adjustment for age, sex, components of the metabolic syndrome, and fitness level (p = 0.0005). CONCLUSIONS: An inverse linear relationship exists between CRP concentrations and measures of pulmonary function in subjects without pulmonary disease and in never-smokers. These results indicate that systemic inflammation may be linked to early perturbations of pulmonary function.