Associations of plasma fibrinogen levels with established cardiovascular disease risk factors, inflammatory markers, and other characteristics: individual participant meta-analysis of 154,211 adults in 31 prospective studies: the fibrinogen studies collaboration

Elevated plasma fibrinogen, psychological distress, antidepressant use, and hospitalization with depression: two large population-based studies

OBJECTIVES

Low-grade systemic inflammation may contribute to the development of depression. We tested the hypothesis that elevated plasma levels of the inflammatory marker fibrinogen are associated with psychological distress, use of antidepressant medication, and with hospitalization with depression in the general population.

METHODS

We examined 73,367 20-100 year old men and women from two large population-based studies, the Copenhagen General Population Study and the Copenhagen City Heart Study. We measured plasma fibrinogen and recorded symptoms of psychological distress, use of antidepressant medication, and hospitalization with depression in both cross-sectional and prospective studies.

RESULTS

In cross-sectional analyses, a stepwise increase in fibrinogen percentile categories was associated with a stepwise increase in risk of psychological distress, use of antidepressant medication, and hospitalization with depression (p-trend 2×10(-11) to 5×10(-95)). Furthermore, when different classes of antidepressant medication were examined, a stepwise increase in fibrinogen percentile categories was associated with a stepwise increase in risk of use of Selective Serotonin Reuptake Inhibitors and Tricyclic Antidepressants (p-trend 7×10(-18) and 6×10(-7), respectively). In prospective analyses, stepwise increasing fibrinogen percentile categories also associated with stepwise increasing risk of hospitalization with depression (p-trend=7×10(-6)): age and gender adjusted hazard ratios were 1.13 (95% confidence interval 0.70-1.83) for the 25.1-50th percentiles, 1.53 (0.97-2.42) for the 50.1-75th percentiles, 1.82 (1.11-2.97) for the 75.1-90th percentiles, 2.10 (1.12-3.95) for the 90.1-95th percentiles, and 3.23 (1.79-5.85) for the >95th percentiles, versus the 0-25th percentiles.

CONCLUSION

Elevated levels of fibrinogen were associated with psychological distress, use of antidepressant medication, and with hospitalization with depression in 73,367 individuals from the general population, in cross-sectional studies and in prospective studies for hospitalization with depression.

Negative association between trunk fat, insulin resistance and skeleton in obese women

AIM

To evaluate the potential interference of trunk fat (TF) mass on metabolic and skeletal metabolism.

METHODS

In this cross-sectional study, 340 obese women (mean age: 44.8 ± 14 years; body mass index: 36.0 ± 5.9 kg/m(2)) were included. Patients were evaluated for serum vitamin D, osteocalcin (OSCA), inflammatory markers, lipids, glucose and insulin (homeostasis model assessment of insulin resistance, HOMA-IR) levels, and hormones profile. Moreover, all patients underwent measurements of bone mineral density (BMD; at lumbar and hip site) and body composition (lean mass, total and trunk fat mass) by dual-energy X-ray absorptiometry.

RESULTS

Data showed that: (1) high TF mass was inversely correlated with low BMD both at lumbar (P < 0.001) and hip (P < 0.01) sites and with serum vitamin D (P < 0.0005), OSCA (P < 0.0001) and insulin-like growth factor-1 (IGF-1; P < 0.0001) levels; (2) a positive correlation was found between TF and HOMA-IR (P < 0.01), fibrinogen (P < 0.0001) and erythrocyte sedimentation rate (P < 0.0001); (3) vitamin D levels were directly correlated with IGF-1 (P < 0.0005), lumbar (P < 0.006) and hip (P < 0.01) BMD; and (4) inversely with HOMA-IR (P < 0.001) and fibrinogen (P < 0.0005).Multivariate analysis demonstrated that only vitamin D was independent of TF variable.

CONCLUSION

In obese women, TF negatively correlates with BMD independently from vitamin D levels. Reduced IGF-1 and increased inflammatory markers might be some important determinants that account for this relationship.

Paper-filtered coffee increases cholesterol and inflammation biomarkers independent of roasting degree: a clinical trial

OBJECTIVE

The aim of this study was to compare the effects of medium light roast (MLR) and medium roast (MR) paper-filtered coffee on cardiovascular risk factors in healthy volunteers.

METHODS

This randomized crossover trial compared the effects of consuming three or four cups (150 mL) of MLR or MR coffee per day for 4 wk in 20 healthy volunteers. Plasma lipids, lipoprotein(a) (Lp[a]), total homocysteine, and endothelial dysfunction-related inflammation biomarkers, serum glycemic biomarkers, and blood pressure were measured at baseline and after each intervention.

RESULTS

Both roasts increased plasma total cholesterol, low-density lipoprotein-cholesterol, and soluble vascular cell adhesion molecule-1 (sVCAM-1) concentrations (10%, 12%, and 18% for MLR; 12%, 14%, and 14% for MR, respectively) (P < 0.05). MR also increased high-density lipoportein-cholesterol concentration by 7% (P = 0.003). Plasma fibrinogen concentration increased 8% after MR intake (P = 0.01), and soluble E-selectin increased 12% after MLR intake (P = 0.02). No changes were observed for Lp(a), total homocysteine, glycemic biomarkers, and blood pressure.

CONCLUSION

Moderate paper-filtered coffee consumption may have an undesirable effect on plasma cholesterol and inflammation biomarkers in healthy individuals regardless of its antioxidant content.

Fibrinogen and future cardiovascular disease in people with diabetes: aetiological associations and risk prediction using individual participant data from nine community-based prospective cohort studies

AIMS

We assessed the associations of fibrinogen levels with cardiovascular disease (CVD) risks in people with and without diabetes, and quantified the value of adding fibrinogen to the established predictive algorithms for CVD.

METHODS

We used Cox models to analyse data from prospective cohorts totalling 33,091 adults (1006 with diabetes) who took part in British and Scottish general population-based health surveys. Discrimination was assessed through c-statistic.

RESULTS

During a median follow-up of 116 months, 351 deaths (119 CVD) were recorded in participants with diabetes and 4157 deaths (1167 CVD) in those without. After adjustment for age and sex, fibrinogen (per standard deviation log(e)) was positively associated with a 34% (26-42%) higher risk of cardiovascular disease and 30% (26-35%) greater risk all-cause mortality. These associations were log-linear, similar in people with and without diabetes (p-value for interaction ≥0.21), robust to the adjustment of additional major CVD risk factors. Adding fibrinogen to a model containing conventional CVD risk factors resulted in only modest improvement in risk prediction.

CONCLUSIONS

The associations of fibrinogen with CVD and all-cause mortality are broadly similar in people with and without diabetes status. Improvement in predictive accuracy after adding fibrinogen to established risk factors is not clinically important.

The biological effects of individual-level PM(2.5) exposure on systemic immunity and inflammatory response in traffic policemen

BACKGROUND

Ambient fine-particle particulate matter (PM2.5) exposure is associated with the decline in pulmonary function, prevalence of coronary heart disease and incidence of myocardial infarction. The study is to observe the effects of ambient PM2.5 on the cardiovascular system and to explore the potential inflammatory and immune mechanisms.

METHODS

The subjects included 110 traffic policemen in Shanghai, China, who were aged 25-55 years. Two-times continuous 24 h individual-level PM2.5 measurements were performed in winter and summer, respectively. The inflammatory marker (high-sensitivity C-reactive protein, hs-CRP), immune parameters (IgA, IgG, IgM and IgE) and lymphocyte profiles (CD4 T cells, CD8 T cells, CD4/CD8 T cells) were measured in blood. The associations between individual-level PM2.5 and inflammatory marker and immune parameters were analysed by multiple linear regression.

RESULTS

The average concentration of 24 h personal PM2.5 for participants was 116.98 μg/m(3) and 86.48 μg/m(3) in winter and summer, respectively. In the main analysis, PM2.5 exposure is associated with the increases in hs-CRP of 1.1%, IgG of 6.7%, IgM of 11.2% and IgE of 3.3% in participants, and decreases in IgA of 4.7% and CD8 of 0.7%, whereas we found no statistical association in CD4 T cells and CD4/CD8 T cells. In the adjusted model, the results showed that the increase of PM2.5 was associated with the changes of inflammatory markers and immune markers both in winter and summer.

CONCLUSIONS

Traffic policeman have been a high-risk group suffering inflammatory response or immune injury because of the high exposure to PM2.5. These findings provided new insight into the mechanisms linking ambient PM2.5 and inflammatory and immune response.

13-year long-term associations between changes in traditional cardiovascular risk factors and changes in fibrinogen levels: the Coronary Artery Risk Development in Young Adults (CARDIA) study

OBJECTIVE

Cross-sectional and prospective studies have linked cardiovascular events and traditional risk factors (TRFs) with higher plasma fibrinogen levels. In a young cohort, we sought to determine longitudinal associations between changes in/development of TRFs and fibrinogen levels over 13 years.

METHODS

We included 2525 adults from the CARDIA study, aged 25-37 with fibrinogen and TRFs measured at year 7 (study baseline; 1992-1993); and year 20 (follow-up). Multiple linear regressions were used to compare mean changes in fibrinogen to TRFs.

RESULTS

Mean fibrinogen increased by 71 mg/dL vs. 70 mg/dL (p = NS) in black vs. white men, and 78 mg/dL vs. 68 mg/dL (p < 0.05) in black vs. white women, respectively over 13 years. After multivariable adjustments, fibrinogen generally rose with increasing BMI (p < 0.001; all sex/race groups), LDL cholesterol, log triglycerides and diastolic blood pressure; and fell with increasing HDL cholesterol and physical activity. 13-year increase in fibrinogen for persons who quit smoking or became non-obese were comparable (p = NS) to that of never-smokers and never-obese persons.

CONCLUSIONS

Among young black and white men and women with few baseline cardiovascular risk factors, fibrinogen tracked longitudinally with changes in TRFs over 13 years through middle age. There was a strong inverse longitudinal relationship between modifiable risk factors (weight loss/smoking cessation) and 13-year change in fibrinogen. Our study helps provide some insight into the role of fibrinogen as a disease marker in the associations between fibrinogen and CVD.

Long-term change in alcohol-consumption status and variations in fibrinogen levels: the coronary artery risk development in young adults (CARDIA) study

OBJECTIVE

To examine long-term associations between change in alcohol-consumption status and cessation of alcohol use, and fibrinogen levels in a large, young, biracial cohort.

DESIGN

Analysis of covariance models were used to analyse participants within the Coronary Artery Risk Development in Young Adults Study (CARDIA) cohort who had fibrinogen and alcohol use data at year 7 (1992-1993; ages 25-37) and year 20 examinations.

SETTING

4 urban US cities.

PATIENTS

2520 men and women within the CARDIA cohort.

MAIN OUTCOME MEASURES

13-year changes in alcohol use related to changes in fibrinogen.

RESULTS

Over 13 years, mean fibrinogen increased by 71 vs 70 mg/dL (p=NS) in black men (BM) versus white men (WM), and 78 vs 68 mg/dL (p<0.05) in black women (BW) versus white women (WW), respectively. Compared with never-drinkers, there were smaller longitudinal increases in fibrinogen for BM, BW and WW (but a larger increase in WM) who became or stayed drinkers, after multivariable adjustment. For BM, WM and WW, fibrinogen increased the most among persons who quit drinking over 13 years (p<0.001 for WM (fibrinogen increase=86.5 (7.1) (mean (SE))), compared with never-drinkers (fibrinogen increase=53.1 (5.4)).

CONCLUSIONS

In this young cohort, compared with the participants who never drank, those who became/stayed drinkers had smaller increases, while those who quit drinking had the highest increase in fibrinogen over 13 years of follow-up. The results provide a novel insight into the mechanism for the established protective effect of moderate alcohol intake on cardiovascular disease outcomes.

Conditioned media from (pre)adipocytes stimulate fibrinogen and PAI-1 production by HepG2 hepatoma cells

Background:

Obesity is associated with a prothrombotic state, which may contribute to the increased risk of thrombotic events.

Objective:

To assess the effects of (pre)adipocyte-derived adipokines on fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF) production by hepatocytes.

Methods:

HepG2 hepatocytes were incubated with conditioned media (CM) derived from preadipocytes and adipocytes, which had been untreated or prestimulated with tumor necrosis factor (TNF)-α, interleukin (IL)-1β or IL-6. After 24 h, supernatants and cell lysates were harvested for measurement of fibrinogen, PAI-1 and TF.

Results:

(Pre)adipocyte CM significantly enhanced the production of PAI-1 by HepG2 cells 2.5- to 4.4-fold. CM from cytokine-stimulated (pre)adipocytes significantly induced fibrinogen secretion 1.5- to 4.2-fold. TF production was not affected by the CM. After specific depletion of TNF-α, IL-1β or IL-6 from the CM, IL-6 was shown to be the most prominent stimulus of fibrinogen secretion and IL-1β of PAI-1 secretion. In addition, fibrinogen, PAI-1 and tissue factor production was evaluated by direct stimulation of HepG2 cells with TNF-α, IL-1β or IL-6. IL-6 enhanced fibrinogen synthesis 4.3-fold (P<0.01), whereas IL-1β induced PAI-1 production 5.0-fold (P<0.01). Gene expression analyses showed that TNF-α and IL-1β stimulate the adipocyte expression of TNF-α, IL-1β and IL-6. Cytokine stimulation of adipocytes may thus have induced an inflammatory response, which may have stimulated fibrinogen and PAI-1 production by HepG2 cells more potently.

Conclusions:

SGBS (pre)adipocytes release cytokines that increase the production of fibrinogen and PAI-1 by HepG2 cells. IL-6 and IL-1β produced by (pre)adipocytes were the strongest inducers of fibrinogen and PAI-1 secretion, respectively.

Plasma fibrinogen levels and restenosis after primary percutaneous coronary intervention

Plasma fibrinogen levels influence restenosis following elective percutaneous coronary intervention (PCI) for stable angina. It is unknown whether the same is true in the setting of primary PCI. The aim of the study was therefore to assess whether fibrinogen levels were associated to 6-month in-stent restenosis (ISR) in STEMI patients undergoing successful primary PCI. From January 2003 to October 2004, 267 patients were admitted to our Institution for STEMI and treated by primary PCI. Of these, 171 patients met the inclusion criteria and were enrolled in our study. Fibrinogen levels were assessed at admission, 12 h, 24 h, 48 h, 72 h following PCI and at discharge. Six-month angiographic follow-up was 100% complete. Subjects with 6-month ISR showed higher fibrinogen levels than patients without ISR. Patients in the upper fibrinogen tertile showed a higher 6-month incidence of symptoms and/or inducible myocardial ischemia (27.1% vs. 7.1%, P = 0.006) and a larger late lumen loss (1.3 ± 0.8 vs. 1.0 ± 0.9 mm, P = 0.049). Logistic regression analysis demonstrated a significant and independent association between fibrinogen levels and ISR. Our study suggests that increased plasma fibrinogen levels are related to ISR in STEMI patients undergoing primary PCI. Larger studies are warranted to assess the prognostic value of fibrinogen over harder end-points.

Patients with prostate cancer treated by ADT have significantly higher fibrinogenemia than healthy control

PURPOSE

Androgen deprivation therapy (ADT) for prostate cancer (PCa) may increase peripheral insulin resistance, induce type 2 diabetes, change body composition, and alter lipoprotein profile. Some studies have reported an association between ADT and increased risk of cardiovascular events. It is known that serum level of fibrinogen (SF) is associated with coronary artery disease and increased cardiovascular risk (CVR). The aim of this study is to determine the increase in SF and C-reactive protein (CRP) of PCa patients on ADT.

METHODS

Ninety-seven patients with locally advanced PCa (study group) were analyzed [mean age 73.4 years ± 6.3 SD, mean prostate specific antigen (PSA) 15.4 ng/ml ± 7.5 SD]. They were examined with blood chemistry including serum cholesterol (CHL), high density lipoproteins (HDL), low density lipoproteins (LDL), very low density lipoproteins, triacylglycerol (TAG), serum fibrinogen (FB), CRP and serum fasting glucose (SFG), serum testosterone, free testosterone at baseline, and after 12 months of ADT.

RESULTS

Patients after 12 months of ADT (study group) had significantly higher overall serum CHL (p < 0.001), higher LDL (p = 0.01), higher FB (p < 0.001), higher serum SFG (p = 0.03) in comparison with the control group. Increase in HDL (p = 0.245) and CRP (p = 0.1) was not significant. Two patients from the study group were diagnosed with new-onset diabetes.

CONCLUSIONS

This is the first study that demonstrates the significant increase in FB in PCa patients on ADT, while CRP as inflammatory marker did not increase. Elevation of SF may contribute to increased CVR in PCa patients. Further prospective studies are warranted to confirm this association.

Fibrinogen gene regulation

The Aα, Bβ and γ polypeptide chains of fibrinogen are encoded by a three gene cluster on human chromosome four. The fibrinogen genes (FGB-FGA-FGG) are expressed almost exclusively in hepatocytes where their output is coordinated to ensure a sufficient mRNA pool for each chain and maintain an abundant plasma fibrinogen protein level. Fibrinogen gene expression is controlled by the activity of proximal promoters which contain binding sites for hepatocyte transcription factors, including proteins which influence fibrinogen transcription in response to acute-phase inflammatory stimuli. The fibrinogen gene cluster also contains cis regulatory elements; enhancer sequences with liver activities identified by sequence conservation and functional genomics. While the transcriptional control of this gene cluster is fascinating biology, the medical impetus to understand fibrinogen gene regulation stems from the association of cardiovascular disease risk with high level circulating fibrinogen. In the general population this level varies from about 1.5 to 3.5 g/l. This variation between individuals is influenced by genotype, suggesting there are genetic variants contributing to fibrinogen levels which reside in fibrinogen regulatory loci. A complete picture of how fibrinogen genes are regulated will therefore point towards novel sources of regulatory variants. In this review we discuss regulation of the fibrinogen genes from proximal promoters and enhancers, the influence of acute-phase stimulation, post-transcriptional regulation by miRNAs and functional regulatory variants identified in genetic studies. Finally, we discuss the fibrinogen locus in light of recent advances in understanding chromosomal architecture and suggest future directions for researching the mechanisms that control fibrinogen expression.

Sex-based differences in the inflammatory profile of peripheral artery disease and the association with primary patency of lower extremity vein bypass grafts

OBJECTIVE

This study was conducted to determine if there are sex-based differences in the inflammatory phenotype of patients undergoing lower extremity bypass (LEB) and if they correlate with clinical outcomes.

METHODS

This was a retrospective analysis of a prospective cohort of 225 patients (161 men and 64 women) who underwent autogenous vein LEB between February 2004 and May 2008. Fasting baseline blood samples were obtained before LEB, and the inflammatory biomarkers high-sensitivity C-reactive protein (CRP) and fibrinogen were assessed. All patients underwent ultrasound graft surveillance. CRP levels were dichotomized at 5 mg/L and fibrinogen levels at 600 mg/dL.

RESULTS

There were no significant differences in age, race, history of hypertension or diabetes mellitus, body mass index, or coronary artery disease between men and women. Men were more likely to be current smokers (P = .02), have a history of hypercholesterolemia (P = .02), and be taking statins (P = .02). Women were more likely to present with critical limb ischemia (P = .03) and had higher median baseline CRP levels (5.15 mg/L; interquartile range [IQR], 1.51-18.62 mg/L) than men (2.70; IQR, 1.24-6.98 mg/L; P = .02). Median follow-up was 893 days (IQR, 539-1315 days). A multivariable Cox proportional hazards model for primary vein graft patency showed a significant interaction between sex and CRP (P = .03) and fibrinogen (P = .02). After adjustment for key covariates, primary vein graft patency was significantly less in women with CRP >5 mg/L compared with women with CRP <5 mg/L (P = .02). No such difference was seen in men (P = .95). Primary graft patency was also decreased in women with fibrinogen >600 mg/dL vs women with fibrinogen <600 mg/dL (P = .002); again, this pattern was not evident in men (P = .19).

CONCLUSIONS

Women undergoing LEB for advanced peripheral artery disease have a different inflammatory phenotype than men. Elevated baseline levels of CRP and fibrinogen are associated with inferior vein graft patency in women but not in men. These findings indicate an important interaction between sex and inflammation in the healing response of vein grafts for LEB. Women with elevated preoperative CRP and fibrinogen levels may benefit from more intensive postoperative graft surveillance protocols.