H. Riese

Diagnostic strategies for C-reactive protein

BackgroundSerum C-reactive protein (CRP) has been identified in prospective epidemiological research as an independent risk marker for cardiovascular disease. In this paper, short-term biological variation of CRP is documented and a strategy to test the reliability of a single CRP sample is proposed.MethodsData were obtained from three groups of healthy volunteers: men, no oral contraceptives (OC-)using women and OC-using women. Blood samples were obtained 3 times in men and twice in women during a workweek.Results and discussionCRP values were highest in the OC-using women, followed by the men, and lowest in the no OC-using women. Averaged over the three groups the within-subject coefficients of variation (CVi) was 49.24% for CRP, and 29.90% for lnCRP. Using the repeated measures, individual samples were identified that reflected a suspicious unreliable high value, i.e. a value that was more than 2 standard deviations higher than the lowest value obtained from the same subject. In an a posteriori analysis, three strategies to identify these suspicious high CRP values were then tested. In terms of maximizing detection of suspicious values and minimizing unnecessary resampling, best results were obtained for the most pragmatic criterion of using an absolute level, stratified for gender, and OC-use, to decide whether a second sample should be obtained.ConclusionA single high CRP value must be followed by re-sampling when it is above 1.75 mg/l for men, above 1.00 mg/l for no OC-using women, and above 2.00 mg/l for OC-using women.

Waist circumference and VO2max are associated with metabolic and hemostatic risk in premenopausal nurses

In 21 nurses (34.4±3.9 yr), VO2max, physical activity, body composition and lifestyle parameters were measured to determine which of these characteristics are related to metabolic and hemostatic risk for cardiovascular disease. Physical activity was assessed with the 7‐day recall interview. VO2max was measured in a progressive and continuous treadmill test to volitional fatigue. Fasting insulin, total cholesterol, HDL‐C, triglycerides, fibrinogen, tPA‐act, tPA‐ag, and PAI‐1‐ag were determined from fasting blood samples. Contrary to our expectation, there was no association of physical activity with any of these risk indicators. High VO2max was associated with lower levels of insulin and fibrinogen. Regression analyses indicated that metabolic and hemostatic risk indicators, as measured in healthy premenopausal nurses, were mainly predicted by waist circumference and oral contraceptive use.