Age-related influences on markers of inflammation and fibrinolysis.

Abstract

Purpose. The primary purpose of this investigation was to determine if age is associated with blood markers of inflammation (C-reactive protein [CRP]) and fibrinolysis (fibrinogen, tissue plasminogen activator [t-PA], and plasminogen activator inhibitor - 1 [PAI-1]), independent of body fat and physical activity levels.

Conclusions. The primary finding of the current study is that age is not independently associated with blood concentrations of CRP, fibrinogen, tPA or PAI-1. However, it was observed that inflammation and fibrinolysis were associated with blood pressure, cholesterol levels, and measures of body fatness. These associations provide a possible explanation for the discrepancy between our findings and those of previous studies which did not control for such factors.

Results. Age was not associated with concentrations of CRP (r = -0.073, p = 0.519). CRP was significantly correlated (p < 0.05) to HDL levels (r = -0.255), BMI (r = 0.304), percent body fat (r = 0.221) and trunk fat mass (r = 0.234). Of these, BMI was the only significant predictor (r2 = 0.095, p = 0.002) of CRP levels. Age was not correlated with fibrinogen (r = 0.206, p = 0.065), or PAI-1 (r = 0.084, p = 0.454), but was initially correlated with t-PA (r = 0.228, p = 0.042). The markers of fibrinolysis were correlated (p < 0.05) with blood pressure, HDL, triglycerides, percent body fat, body fat mass, percent trunk fat, and trunk fat mass. However, none of these variables or age were independent predictors of blood concentrations of fibrinogen (r2 = 0.237, p = 0.226), t-PA (r2 = 0.079, p = 0.636), or PAI - 1 (r2 = 0.137, p = 0.333).

Methods. A total of 40 healthy males and 42 healthy females ranging in age from 21 to 89 years participated in this cross-sectional study. Blood levels of CRP, fibrinogen, t-PA, and PAI-1 were measured and compared with age, clinical characteristics, physical activity levels, and body composition. Body composition was assessed with dual-energy x-ray absorptiometry and physical activity was assessed with a StepWatch Activity Monitor.