Association between physical activity and markers of inflammation in a healthy elderly population.

Higher levels of physical activity are associated with lower risk of cardiovascular disease. There is growing evidence that the development of the atherosclerotic plaque is associated with inflammation. In this study, the authors investigated the cross-sectional association between physical activity and markers of inflammation in a healthy elderly population. Data obtained in 1989-1990 and 1992-1993 from the Cardiovascular Health Study, a cohort of 5,888 men and women aged >/=65 years, were analyzed. Concentrations of the inflammation markers-C-reactive protein, fibrinogen, Factor VIII activity, white blood cells, and albumin-were compared cross-sectionally by quartile of self-reported physical activity. Compared with persons in the lowest quartile, those in the highest quartile of physical activity had 19%, 6%, 4%, and 3% lower concentrations of C-reactive protein, white blood cells, fibrinogen, and Factor VIII activity, respectively, after adjustment for gender, the presence of cardiovascular disease, age, race, smoking, body mass index, diabetes, and hypertension. Multivariate regression models suggested that the association of higher levels of physical activity with lower levels of inflammation markers may be mediated by body mass index and glucose. There was no association between physical activity and albumin. Higher levels of physical activity were associated with lower concentrations of four out of five inflammation markers in this elderly cohort. These data suggest that increased exercise is associated with reduced inflammation. Prospective studies will be required for verification of these findings.

The measurement of fibrinogen in population-based research. Studies on instrumentation and methodology.

Plasma fibrinogen concentration is a risk factor for cardiovascular disease and has become a common component of epidemiologic studies. Also, fibrinogen analysis has become an important component of clinical trials of thrombolytic therapy and anticoagulation. We studied fibrinogen values from plasma containing three different anticoagulants and compared two different instruments. Clot-rate assays were performed on plasma containing sodium citrate (the recommended specimen) as well as ethylenediamine-tetraacetic acid (EDTA) and EDTA plus D-Phe-Pro-Arg chloromethyl ketone (PPACK) and aprotinin (special anticoagulant), specimens often obtained in multicenter studies. We compared a fibrometer (the BBL) with an analyzer (the Diagnostica Stago ST4), which offers improved throughput, ease of use, and precision. The correlation of citrate and EDTA fibrinogen values (fibrometer) was r = .9718; for citrate and special anticoagulant plasma, r = .9717. Correlations of fibrinogen values from the fibrometer and the analyzer were r = .9558 and r = .9857 for citrate samples and special anticoagulant samples, respectively. We conclude that (1) fibrinogen may be measured by clot-rate assay in EDTA-containing samples and that values may be compared with values obtained from citrate plasma with a correction; (2) samples containing PPACK may be used with only slight modification of the method; and (3) values obtained on the analyzer are directly comparable with those obtained on the fibrometer, facilitating large studies.