INTRAINDIVIDUAL AND INTERINDIVIDUAL VARIABILITY OF HEMOSTATIC FACTORSAND TRADITIONAL CARDIOVASCULAR RISK-FACTORS IN A 3-YEAR FOLLOW-UP

Elucidation of the key role of thrombosis in cardiovascular disease ev ents has arisen considerable interest in hemostatic factors and in the repeatability of their determinations. Data on long-term repeatabilit y has, however, remained scanty. We examined twice 208 men and 265 wom en in North Karelia, eastern Finland. The baseline examination was a p art of the FINRISK 1992 Hemostasis Study and the age-range of particip ants was between 45-64 years. The re-examination took place three year s later in 1995. Both surveys followed the same protocol and were carr ied out during the same season. Spearman rank correlation coefficients between 1992 and 1995 measurements of fibrinogen, factor VII coagulan t activity (FVII:C), factor VII antigen (FVII:Ag), and plasminogen wer e among men 0.72, 0.77, 0.46 and 0.56, respectively. For total cholest erol, HDL-cholesterol, triglycerides and diastolic blood pressure the corresponding coefficients were 0.74, 0.83, 0.66, and 0.54. In women, the coefficient of fibrinogen was lower than in men, 0.62, otherwise t he results were similar. Of men belonging to the highest quarter of fi brinogen, FVII:C, FVII:Ag and plasminogen in 1992, 65%, 60%, 53% and 6 0% belonged to the highest quarter of respective distributions also in 1995. In women, the corresponding proportions were 61%, 65%, 46% and 58%. The modest repeatability of FVII:Ag and plasminogen was mainly du e to the high intraindividual variability. However, in comparisons of plasma levels between two groups, relatively small sample sizes seemed to give adequate statistical power to detect possible differences in FVII:Ag and plasminogen. In conclusion, the long-term repeatability of fibrinogen and FVII:C is similar to that of triglycerides and even be tter than that of diastolic blood pressure, but somewhat lower than th e repeatability of total cholesterol. FVII:Ag and plasminogen did not have very good repeatability and more than one measurement of them sho uld be considered if they are used as predictors of cardiovascular dis ease in prospective studies.