Biomedical subjects

Ann Rumley

Publications and source records attributed to Ann Rumley.

At least 37 records · Page 2Linked to original sources

PubMed2005

High-density lipoprotein particles may regulate hemostasis in human pregnancy.

We explored the association of apolipoprotein A-I (the major protein constituent of high-density lipoprotein (HDL)) and fibrin fragment D-dimer (a marker of cross-linked fibrin turnover) in pregnant women. A significant inverse correlation between the levels of apolipoprotein A-I and fibrin fragment D-dimer was observed in both pre-eclamptic and normal pregnant women (rs = -0.459, n = 37 and rs = -0.290, n = 55, respectively), suggesting a major regulating role of HDL in hemostasis during pregnancy.

Female↗

PubMed2005

Cardiovascular risk parameters in men with ankylosing spondylitis in comparison with non-inflammatory control subjects: relevance of systemic inflammation.

Men with AS (ankylosing spondylitis) are at elevated risk for CHD (coronary heart disease) but information on risk factors is sparse. We compared a range of conventional and novel risk factors in men with AS in comparison with healthy controls and, in particular, determined the influence of systemic inflammation. Twenty-seven men with confirmed AS and 19 controls matched for age were recruited. None of the men was taking lipid-lowering therapy. Risk factors inclusive of plasma lipids, IL-6 (interleukin-6), CRP (C-reactive protein), vWF (von Willebrand factor), fibrin D-dimer, ICAM-1 (intercellular cell-adhesion molecule-1) and fibrinogen were measured, and blood pressure and BMI (body mass index) were determined by standard techniques. A high proportion (70%) of men with AS were smokers compared with 37% of controls (P = 0.024). The AS patients also had a higher BMI. In analyses adjusted for BMI and smoking, men with AS had significantly higher IL-6 and CRP (approx. 9- and 6-fold elevated respectively; P < 0.001), fibrinogen (P = 0.013) and vWF (P = 0.008). Total cholesterol and HDL-C (high-density lipoprotein cholesterol) were lower (P < 0.05 and P = 0.073 respectively) in AS and thus the ratio was not different. Pulse pressure was also significantly higher in AS (P = 0.007). Notably, adjustment for IL-6 and CRP levels rendered all case-control risk factor differences, except pulse pressure, non-significant. In accordance with this finding, IL-6 correlated positively (r = 0.74, P < 0.001) with fibrinogen, but negatively (r = -0.46, P = 0.016) with total cholesterol concentration. In conclusion, men with AS have perturbances in several CHD risk factors, which appear to be driven principally by systemic inflammatory mediators. Inflammation-driven atherogenesis potentially contributes to the excess CHD risk in AS.

Adult↗

PubMed2005

Randomized controlled trial of homocysteine-lowering vitamin treatment in elderly patients with vascular disease.

BACKGROUND: Homocysteine is an independent risk factor for vascular disease and is associated with dementia in older people. Potential mechanisms include altered endothelial and hemostatic function. OBJECTIVE: We aimed to determine the effects of folic acid plus vitamin B-12, riboflavin, and vitamin B-6 on homocysteine and cognitive function. DESIGN: This was a factorial 2 x 2 x 2, randomized, placebo-controlled, double-blind study with 3 active treatments: folic acid (2.5 mg) plus vitamin B-12 (500 microg), vitamin B-6 (25 mg), and riboflavin (25 mg). We studied 185 patients aged >or=65 y with ischemic vascular disease. Outcome measures included plasma homocysteine, fibrinogen, and von Willebrand factor at 3 mo and cognitive change (determined with the use of the Letter Digit Coding Test and on the basis of the Telephone Interview of Cognitive Status) after 1 y. RESULTS: The mean (+/-SD) baseline plasma homocysteine concentration was 16.5 +/- 6.4 micromol/L. This value was 5.0 (95% CI: 3.8, 6.2) micromol/L lower in patients given folic acid plus vitamin B-12 than in patients not given folic acid plus vitamin B-12 but did not change significantly with vitamin B-6 or riboflavin treatment. Homocysteine lowering with folic acid plus vitamin B-12 had no significant effect, relative to the 2 other treatments, on fibrinogen, von Willebrand factor, or cognitive performance as measured by the Letter Digit Coding Test (mean change: -1; 95% CI: -2.3, 1.4) and the Telephone Interview of Cognitive Status (-0.7; 95% CI: -1.7, 0.4). CONCLUSION: Oral folic acid plus vitamin B-12 decreased homocysteine concentrations in elderly patients with vascular disease but was not associated with statistically significant beneficial effects on cognitive function over the short or medium term.

Aged↗

PubMed2005

Associations of fibrinogen and C-reactive protein with prevalent and incident coronary heart disease are attenuated by adjustment for confounding factors. British Women's Heart and Health Study.

A cross sectional and prospective analysis of 3,745 British women aged 60-79 years at baseline was undertaken. Among these women there were 570 prevalent cases of coronary heart disease (CHD) and 151 new cases among 12,641 person-years of follow up of women who were free of CHD at baseline. Both fibrinogen and CRP were associated with indicators of socioeconomic position in childhood and adulthood and there was a cumulative effect of socioeconomic position from across the life course. The age-adjusted odds ratio (95% confidence interval) of prevalent CHD for a 1 unit (1 g/L) increase in fibrinogen was 1.29 (1.12, 1.49); with full adjustment for all potential confounding factors this attenuated to 1.09 (0.93, 1.28). The hazards ratio for incident CHD among those free of disease at baseline was 1.28 (1.00, 1.64); with full adjustment for all potential confounding factors this attenuated to 1.09 (0.84, 1.44). Similar effects of adjustment for confounding factors were seen for the associations between CRP and both prevalent and incident CHD. By contrast, the strong positive association between smoking (an established causal risk factor for CHD) and CHD was not attenuated by adjustment for life course socioeconomic position or other risk factors. We conclude that fibrinogen and CRP predict CHD but may not be causally related to it.

Age Factors↗

PubMed2004

Association of European population levels of thrombotic and inflammatory factors with risk of coronary heart disease: the MONICA Optional Haemostasis Study.

AIMS: Classical risk factors do not fully explain international differences in risk of coronary heart disease (CHD). We therefore measured thrombotic and inflammatory markers in a substudy of the WHO MONICA project and correlated these with CHD event rates. METHODS AND RESULTS: We measured levels of fibrinogen (clottable and nephelometric), von Willebrand factor (vWf), tissue plasminogen activator antigen, plasminogen activator inhibitor activity, fibrin D-dimer, plasma viscosity, C-reactive protein, and total cholesterol in 12 MONICA populations (listed at the end of this paper), all but one European. Men and women aged 45-64 years were studied from 10 countries. All samples were collected using a carefully standardized protocol, and analysed centrally. Results were available for 3996 subjects (nephelometric fibrinogen and viscosity), 2378 subjects (other thrombotic assays), and 1757 subjects (C-reactive protein and total cholesterol). Significant differences in levels of thrombotic and inflammatory factors exist in MONICA populations mainly from European countries. These differences persist after adjustment for age, smoking habit, and body mass index. Cross-sectional correlations between coronary event rates and these thrombotic/inflammatory markers were significant for vWF antigen in both sexes, nephelometric fibrinogen in men, and D-dimer in women. CONCLUSION: In particular, vWF, nephelometric fibrinogen, and D-dimer should be examined in further research as potential risk factors which may help explain differences in coronary risk between European populations.

Biomarkers↗

PubMed2004

Interleukin-6, fibrin D-dimer, and coagulation factors VII and XIIa in prediction of coronary heart disease.

OBJECTIVE: Activated inflammation and activated blood coagulation are believed to increase the risk of coronary thrombosis and are related. We therefore compared plasma IL-6 (a key cytokine in the inflammatory process), fibrin D-dimer (a marker of fibrin turnover), and coagulation factors VII and XIIa (initiators of extrinsic and intrinsic blood coagulation, respectively) as predictors of coronary risk in the West of Scotland Coronary Prevention Study of pravastatin in men with hypercholesterolemia. METHODS AND RESULTS: 485 men who had had a coronary event (nonfatal myocardial infarction, death from coronary heart disease, or revascularization) were matched for age and smoking status with 934 controls. Baseline IL-6 and D-dimer were strong univariate predictors of coronary risk (relative risk in the highest quintile approximately twice that in the lowest quintile) and were associated with each other and with C-reactive protein. On multivariate analyses, D-dimer retained a significant association with coronary risk (relative risk, 1.86; 95% CI, 1.24 to 2.80), whereas IL-6 (1.47; 0.95 to 2.28) and C-reactive protein (1.33; 0.85 to 2.08) did not. Neither factor VII nor factor XIIa antigens were predictors of coronary events. CONCLUSIONS: Fibrin D-dimer may be a stronger predictor of coronary risk than inflammatory markers, perhaps through its ability to stimulate monocyte release of IL-6.

Angioplasty, Balloon, Coronary↗

PubMed2004

Hemostatic function and progressing ischemic stroke: D-dimer predicts early clinical progression.

BACKGROUND AND PURPOSE: Early clinical progression of ischemic stroke is common and is associated with increased risk of death and dependency. We hypothesized that activation of the coagulation system is an important contributor in some cases of deterioration. We aimed to characterize alterations in circulating hemostatic markers in patients with progressing stroke. METHODS: Consecutive acute ischemic stroke admissions were recruited. Progressing stroke was defined by deterioration in components of the Scandinavian Stroke Scale. Hemostatic markers (coagulation factors VIIc, VIIIc, and IXc, prothrombin fragments 1+2 [F1+2], thrombin-antithrombin complexes [TAT], D-dimer, fibrinogen, von Willebrand factor [vWF] and tissue plasminogen activator) were measured within 24 hours of symptom recognition. RESULTS: Fifty-four (25%) of the 219 patients met criteria for progressing stroke. F1+2 (median 1.28 versus 1.06 nmol/L, P=0.01), TAT (5.28 versus 4.07 microg/L, P<0.01), D-dimer (443 versus 194 ng/mL, P<0.001) and vWF (216 versus 198 IU/dL, P<0.05) levels were higher in these patients than in stable/improving patients. In logistic regression analysis, with all important clinical and laboratory variables included, only natural log D-dimer (odds ratio [OR]: 1.87; 95% confidence interval [CI]: 1.38 to 2.54; P=0.0001) and mean arterial blood pressure (OR: 1.26 per 10 mm Hg change; 95% CI: 1.05 to 1.51; P=0.01) remained independent predictors of progressing stroke. CONCLUSIONS: There is evidence of excess thrombin generation and fibrin turnover in patients with progressing ischemic stroke. Measurement of D-dimer levels can identify patients at high risk for stroke progression. Further research is required to determine whether such patients benefit from acute interventions aimed at modifying hemostatic function.

Aged↗

PubMed2004

C-reactive protein and other circulating markers of inflammation in the prediction of coronary heart disease.

BACKGROUND: C-reactive protein is an inflammatory marker believed to be of value in the prediction of coronary events. We report data from a large study of C-reactive protein and other circulating inflammatory markers, as well as updated meta-analyses, to evaluate their relevance to the prediction of coronary heart disease. METHODS: Measurements were made in samples obtained at base line from up to 2459 patients who had a nonfatal myocardial infarction or died of coronary heart disease during the study and from up to 3969 controls without a coronary heart disease event in the Reykjavik prospective study of 18,569 participants. Measurements were made in paired samples obtained an average of 12 years apart from 379 of these participants in order to quantify within-person fluctuations in inflammatory marker levels. RESULTS: The long-term stability of C-reactive protein values (within-person correlation coefficient, 0.59; 95 percent confidence interval, 0.52 to 0.66) was similar to that of both blood pressure and total serum cholesterol. After adjustment for base-line values for established risk factors, the odds ratio for coronary heart disease was 1.45 (95 percent confidence interval, 1.25 to 1.68) in a comparison of participants in the top third of the group with respect to base-line C-reactive protein values with those in the bottom third, and similar overall findings were observed in an updated meta-analysis involving a total of 7068 patients with coronary heart disease. By comparison, the odds ratios in the Reykjavik Study for coronary heart disease were somewhat weaker for the erythrocyte sedimentation rate (1.30; 95 percent confidence interval, 1.13 to 1.51) and the von Willebrand factor concentration (1.11; 95 percent confidence interval, 0.97 to 1.27) but generally stronger for established risk factors, such as an increased total cholesterol concentration (2.35; 95 percent confidence interval, 2.03 to 2.74) and cigarette smoking (1.87; 95 percent confidence interval, 1.62 to 2.16). CONCLUSIONS: C-reactive protein is a relatively moderate predictor of coronary heart disease. Recommendations regarding its use in predicting the likelihood of coronary heart disease may need to be reviewed.

Aged↗

PubMed2004

Extent of regression dilution for established and novel coronary risk factors: results from the British Regional Heart Study.

BACKGROUND: Imprecision in measurement of risk factors leads to underestimation of associations with disease outcomes (through regression dilution bias). We examine the extent of this bias for established and novel risk factors for coronary heart disease (CHD) and consider the consequences for CHD prevention. DESIGN: Prospective cardiovascular study of middle-aged British men followed up over 20 years. METHODS: Repeated measurements of blood lipids, blood pressure and insulin were available at intervals of 1 week, 4, 16 and 20 years; repeated measurements of homocysteine and haemostatic factors were available over 1 week and 4 years. RESULTS: The use of single baseline measures of both established and novel risk factors in analysis results in marked underestimation of risk associations, increasing over time. The use of a single baseline measurement of total cholesterol results in a 47% (95% confidence interval 44 to 50%) underestimation of its association with CHD risk during the third decade of follow-up; for diastolic blood pressure the corresponding underestimation is 76% (95% confidence interval 73 to 78%). Ignoring the consequences of regression dilution can also lead to error in the assessment of other risk markers, even those measured precisely. CONCLUSIONS: The importance of risk factors for CHD can be greatly underestimated by using a single baseline measure in prospective study analyses. Studies that wish to estimate associations between disease risk and usual exposure levels need to take regression dilution effects into account. Failure to do so can lead to serious misinterpretation of the importance of CHD risk factors.

Adult↗

PubMed2004

Low-intensity warfarin reduces thrombin generation and fibrin turnover, but not low-grade inflammation, in men at risk of myocardial infarction.

In the Thrombosis Prevention Trial (TPT), low-intensity warfarin reduced the risk of first coronary events only when the achieved international normalized ratio (INR) was > or =1.4. To validate the likely mechanism of action of low-intensity warfarin we measured its effects on plasma markers of thrombin generation, fibrin turnover and low-grade inflammation in TPT participants. D-dimer and prothrombin fragment F1.2 levels were lower at INRs > or =1.4 (P = 0.02 and 0.03 respectively); levels fell as INR increased (P for trend 0.04 and 0.002 respectively). C-reactive protein did not vary with INR. The efficacy of warfarin is related to reductions in thrombin generation and fibrin turnover.

Anticoagulants↗

PubMed2004

Plasma fibrinogen.

Fibrinogen is the major plasma protein coagulation factor. Low plasma fibrinogen concentrations are therefore associated with an increased risk of bleeding due to impaired primary and secondary haemostasis. Fibrinogen is a classical positive acute-phase reactant protein and is an independent predictor of coronary heart disease events. This review considers available methods for measurement of fibrinogen and makes recommendations as to their appropriate use. Total clottable fibrinogen assays are the definitive and reference method for plasma fibrinogen measurement. However, they are time-consuming and are rarely required in clinical practice. Clotting rate assays remain the routine method of choice for investigation, monitoring and treatment of bleeding disorders associated with low plasma fibrinogen concentrations. They are appropriately sited in haematology or haemostasis laboratories, with facilities for further relevant investigations, and expert advice from consultant haematologists on appropriate management. They have also been used in the majority of studies investigating increasing fibrinogen concentrations as a cardiovascular risk factor. Prothrombin-time derived assays are widely used, because they are less expensive and come at no extra cost with prothrombin time assays. However, their results vary widely with analysers and reagents, show discrepancies with clotting rate assays for both low and normal plasma fibrinogen samples, and at present they are not recommended by routine clinical use. Immunoassays (radial immunodiffusion, enzyme-linked immunosorbent assay or nephelometric) are useful in (a) differentiating hypofibrinogenaemia from dysfibrinogenaemia, and (b) assessing cardiovascular risk and acute-phase reactions. Unlike clottable fibrinogen assays, immunoassays can be performed in dipotassium edetate anticoagulated samples.

Biomarkers↗

PubMed2003

Relationship of the platelet glycoprotein PlA and fibrinogen T/G+1689 polymorphisms with peripheral arterial disease and ischaemic heart disease.

INTRODUCTION: Genetic variation in plasma fibrinogen and the platelet receptor GP IIIa locus has been independently associated with increased risks of ischaemic heart disease, but there have been few reports on the relationship with peripheral arterial disease. This study determined the risk of peripheral arterial disease and ischaemic heart disease associated with polymorphisms of fibrinogen T/G(+1689) and platelet glycoprotein Pl(A) genes and the effects of cigarette smoking and fibrinogen. MATERIALS AND METHODS: In the 5-year follow-up phase of the Edinburgh Artery Study, 939 subjects (60-79 years) had DNA extracted from a venous blood sample. One hundred sixteen subjects were identified as having angina, 87 a myocardial infarction, 104 had intermittent claudication and 663 subjects comprised a healthy group. RESULTS: Distribution of the fibrinogen genotype was similar across the disease and healthy groups. Logistic regression analyses found no significant association between fibrinogen genotype and ischaemic heart disease and peripheral arterial disease. A lower percentage of claudicants had the Pl(A2) allele (8.3% vs. 15.2%, p=0.025). After adjustment for age and sex, the risk of IC associated with the Pl(A2) was half that of the homozygous Pl(A1) genotype (OR 0.49, 95% CI 0.25, 0.88; p<==0.05). Adjustment for lifetime smoking and fibrinogen levels increased the odds slightly to nonsignificance. CONCLUSIONS: The Pl(A2) genotype was associated with a decreased risk of developing IC. There was no significant relationship between fibrinogen T/G(+1689) genotype and ischaemic and peripheral heart disease in this older population.

Aged↗

PubMed2003

Total tooth loss and prevalent cardiovascular disease in men and women: possible roles of citrus fruit consumption, vitamin C, and inflammatory and thrombotic variables.

BACKGROUND AND OBJECTIVE: Tooth loss has been associated with cardiovascular disease (CVD), but the mechanisms are unclear. We evaluated the association of total tooth loss with prevalent CVD in men and women; as well as with citrus fruit consumption, plasma vitamin C, and inflammatory and thrombotic variables. METHODS: We used an age-and sex-stratified population survey, of men and women aged 25-74 years, in North Glasgow. RESULTS: Thirty-eight percent of women and 29% of men were edentulous. Total tooth loss was associated with prevalent CVD in both sexes. After adjustment for major potential confounders (age, sex, smoking, and social class), the odds ratio (95% CI) for prevalent CVD was 1.55 (1.13, 2.13) in the edentulous. Total tooth loss was also associated with low citrus fruit consumption and low plasma vitamin C levels, increased plasma C-reactive protein in men, and with increased plasma interleukin-6, fibrinogen, and factor VIII levels in women. CONCLUSION: Prevalent CVD is associated with total tooth loss. Possible mechanisms include low intake of citrus fruit, and hence, low plasma vitamin C levels, and a predisposition to low-grade inflammation and thrombosis. It may be prudent to ensure adequate vitamin C intake in people with no teeth.

Adult↗

PubMed2003

C-reactive protein: associations with haematological variables, cardiovascular risk factors and prevalent cardiovascular disease.

C-reactive protein (CRP) has been proposed as a risk factor for cardiovascular disease; however, this association is confounded by mutual relationships with both classical and haematological cardiovascular risk factors. We, therefore, measured CRP with a high-sensitivity assay in stored plasma samples from 414 men and 515 women in the north Glasgow MONICA (MONItoring trends in CArdiovascular diseases) survey, to study its correlation with haematological variables, classical risk factors and prevalent cardiovascular disease. CRP correlated with age, oral contraceptive use, menopause and most classical cardiovascular risk factors (except blood pressure). CRP also correlated with plasma levels of the pro-inflammatory cytokine interleukin 6, and haematocrit, viscosity, red cell aggregation, white cell count, and coagulation factors [fibrinogen, factor (F) VII in women, FVIII, FIX] and inhibitors (antithrombin and protein C in women; protein S) but not coagulation activation markers. CRP was significantly associated with prevalent cardiovascular disease in both men (P = 0.03) and women (P = 0.009), however, the association became non-significant after adjustment for firstly classical risk factors, then fibrinogen. We conclude that correlations with classical and haematological risk factors account for a substantial component of the association of CRP with prevalent cardiovascular disease, but there is evidence of a residual, independent effect among women.

Adult↗

PubMed2003

Does sticky blood predict a sticky end? Associations of blood viscosity, haematocrit and fibrinogen with mortality in the West of Scotland.

There is increasing evidence that blood viscosity and its major determinants (haematocrit, plasma viscosity and fibrinogen) are associated with an increased risk of incident cardiovascular events; however, their associations with mortality are not established. We therefore studied the associations of these variables with cardiovascular events and total mortality in 1238 men and women aged 25-64 years, followed for 13 years in the first North Glasgow MONICA (MONItoring CArdiovascular disease) survey and West of Scotland centres in the Scottish Heart Health Study. After adjustment for age and sex, increasing whole blood viscosity, plasma viscosity, haematocrit and fibrinogen (analysed by both von Clauss and heat precipitation assays) were significantly associated with mortality. Only the association for fibrinogen (von Clauss assay) remained significant after adjustment for major cardiovascular risk factors. We conclude that clottable fibrinogen may be independently associated with mortality. However, the significance of this association, and the extent to which viscosity is associated with mortality, remain to be established in larger studies and meta-analyses.

Adult↗

PubMed2003

Metabolic, inflammatory and haemostatic effects of a low-dose continuous combined HRT in women with type 2 diabetes: potentially safer with respect to vascular risk?

BACKGROUND: Conventional hormone replacement therapy (HRT) containing conjugated equine oestrogen (CEE) and medroxyprogesterone acetate (MPA) increases triglyceride, C-reactive protein (CRP) and coagulation Factor VII concentrations, potentially explaining their increased coronary heart disease (CHD) and stroke risk. OBJECTIVE: To assess the metabolic effects of a continuous combined HRT containing 1 mg oestradiol and 0.5 mg norethisterone or matching placebo. DESIGN: Double-blind, randomized placebo-controlled trial. PATIENTS: Fifty women with type 2 diabetes. MEASUREMENTS: Classical and novel risk factors for vascular disease. RESULTS: Triglyceride concentration was not altered (P = 0.31, change in active arm relative to placebo) and low-density lipoprotein (LDL) cholesterol concentration declined 13% (P = 0.018). IL-6 concentration (mean difference -1.42 pg/ml, 95% CI: -2-55 to -0-29 IU/dl, P = 0.015), Factor VII (-32 IU/dl, -43 to -21 IU/l, P < 0.001) and tissue plasminogen activator antigen (by 13%, P = 0.005) concentrations fell, but CRP was not significantly altered (P = 0.62). Fasting glucose (P = 0.026) also declined significantly, but there are no significant effects on HBA1c, Factor IX or APC resistance. CONCLUSIONS: HRT containing 1 mg oestradiol and 0.5 mg norethisterone may avoid the adverse metabolic effects potentially implicated in the elevated CHD and stroke risk induced by conventional higher dose HRT. This type of preparation may therefore be more suitable than conventional HRT for women at elevated CHD risk such as those with type 2 diabetes. Large randomized controlled trials of such low dose preparations, powered for cardiovascular end points, are now needed.

Autoantigens↗

PubMed2003

Comparison of plasma fibrinogen by Clauss, prothrombin time-derived, and immunonephelometric assays in a general population: implications for risk stratification by thirds of fibrinogen.

There is strong evidence from meta-analyses of prospective epidemiological studies that increasing plasma fibrinogen levels are associated with increasing risk of ischaemic heart disease. It has been suggested that categorization of plasma fibrinogen by thirds of the population distribution be added to cardiovascular risk prediction equations. However, the heterogeneity of plasma fibrinogen and the resulting discrepancies between commonly performed assays may lead to differences in both mean levels and distributions, and in categorizations of populations by thirds. We therefore compared three commonly performed routine fibrinogen assays in a random population sample of 1373 men and women aged 25-64 years in the fourth World Health Organization MONICA survey in north Glasgow. The two assays of clottable fibrinogen (von Clauss and prothrombin time derived) showed similar mean values and distributions, whereas the immunonephelometric assay showed lower mean values. There was significant disagreement between all three assays in categorization of thirds of population fibrinogen distribution (kappa statistic, 0.64 von Clauss versus prothrombin time derived, 0.46 von Clauss versus immunonephelometric, and 0.51 prothrombin time derived versus immunonephelometric). We conclude that further standardization of plasma fibrinogen assays is desirable for ischaemic heart disease risk stratification, and that further studies of the causes and clinical significance of discrepancies between fibrinogen assays in the general population are indicated.

Adult↗

PubMed2003

Measurement of plasma viscosity in stored frozen samples: a general population study.

To establish whether plasma viscosity could be accurately measured from frozen-stored (instead of fresh) plasma samples in epidemiological studies, we prospectively compared fresh and frozen-stored samples from 1361 men and women aged 25-74 years participating in the Glasgow MONICA survey. Mean plasma viscosity (37 degrees C) was significantly higher (P < 0.0001) in fresh samples (mean = 1.310 mPa/s, standard deviation = 0.079 mPa/s) compared with frozen samples (mean = 1.278 mPa/s, standard deviation = 0.075 mPa/s). However, this difference (mean = 0.030 mPa/s, 95% confidence interval = 0.029-0.031) did not vary significantly with increasing viscosity (kappa statistic for consistency of categorization by thirds = 0.824, standard error = 0.021). We conclude that frozen samples are acceptable for epidemiological studies of plasma viscosity, which should increase their utilization.

Adult↗