26 research outputs found

    Joint Source-Channel Coding Optimized On End-to-End Distortion for Multimedia Source

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    In order to achieve high efficiency, multimedia source coding usually relies on the use of predictive coding. While more efficient, source coding based on predictive coding has been considered to be more sensitive to errors during communication. With the current volume and importance of multimedia communication, minimizing the overall distortion during communication over an error-prone channel is critical. In addition, for real-time scenarios, it is necessary to consider additional constraints such as fix and small delay for a given bit rate. To comply with these requirements, we seek an efficient joint source-channel coding scheme. In this work, end-to-end distortion is studied for a first order autoregressive synthetic source that represents a general multimedia traffic. This study reveals that predictive coders achieve the same channel-induced distortion performance as memoryless codecs when applying optimal error concealment. We propose a joint source-channel system based on incremental redundancy that satisfies the fixed delay and error-prone channel constraints and combines DPCM as a source encoder and a rate-compatible punctured convolutional (RCPC) error control codec. To calculate the joint source-channel coding rate allocation that minimizes end-to-end distortion, we develop a Markov Decision Process (MDP) approach for delay constrained feedback Hybrid ARQ, and we use a Dynamic Programming (DP) technique. Our simulation results support the improvement in end-to-end distortion compared to a conventional Forward Error Control (FEC) approach with no feedback

    Fixed-dose combination therapy for the prevention of atherosclerotic cardiovascular diseases.

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    BACKGROUND: Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death and disability worldwide, yet ASCVD risk factor control and secondary prevention rates remain low. A fixed-dose combination of blood pressure- and cholesterol-lowering and antiplatelet treatments into a single pill, or polypill, has been proposed as one strategy to reduce the global burden of ASCVD. OBJECTIVES: To determine the effect of fixed-dose combination therapy on all-cause mortality, fatal and non-fatal ASCVD events, and adverse events. We also sought to determine the effect of fixed-dose combination therapy on blood pressure, lipids, adherence, discontinuation rates, health-related quality of life, and costs. SEARCH METHODS: We updated our previous searches in September 2016 of CENTRAL, MEDLINE, Embase, ISI Web of Science, and DARE, HTA, and HEED. We also searched two clinical trials registers in September 2016. We used no language restrictions. SELECTION CRITERIA: We included randomised controlled trials of a fixed-dose combination therapy including at least one blood pressure-lowering and one lipid-lowering component versus usual care, placebo, or an active drug comparator for any treatment duration in adults 18 years old or older, with no restrictions on presence or absence of pre-existing ASCVD. DATA COLLECTION AND ANALYSIS: Three review authors independently selected studies for inclusion and extracted the data for this update. We evaluated risk of bias using the Cochrane 'Risk of bias' assessment tool. We calculated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous data with 95% confidence intervals (CI) using fixed-effect models when heterogeneity was low (I2 < 50%) and random-effects models when heterogeneity was high (I2 ≥ 50%). We used the GRADE approach to evaluate the quality of evidence. MAIN RESULTS: In the initial review, we identified nine randomised controlled trials with a total of 7047 participants and four additional trials (n = 2012 participants; mean age range 62 to 63 years; 30% to 37% women) were included in this update. Eight of the 13 trials evaluated the effects of fixed-dose combination (FDC) therapy in populations without prevalent ASCVD, and the median follow-up ranged from six weeks to 23 months. More recent trials were generally larger with longer follow-up and lower risk of bias. The main risk of bias was related to lack of blinding of participants and personnel, which was inherent to the intervention. Compared with the comparator groups (placebo, usual care, or active drug comparator), the effects of the fixed-dose combination treatment on mortality (FDC = 1.0% versus control = 1.0%, RR 1.10, 95% CI 0.64 to 1.89,  I2 = 0%, 5 studies, N = 5300) and fatal and non-fatal ASCVD events (FDC = 4.7% versus control = 3.7%, RR 1.26, 95% CI 0.95 to 1.66, I2 = 0%, 6 studies, N = 4517) were uncertain (low-quality evidence). The low event rates for these outcomes and indirectness of evidence for comparing fixed-dose combination to usual care versus individual drugs suggest that these results should be viewed with caution. Adverse events were common in both the intervention (32%) and comparator (27%) groups, with participants randomised to fixed-dose combination therapy being 16% (RR 1.16, 95% CI 1.09 to 1.25, 11 studies, 6906 participants, moderate-quality evidence) more likely to report an adverse event . The mean differences in systolic blood pressure between the intervention and control arms was -6.34 mmHg (95% CI -9.03 to -3.64, 13 trials, 7638 participants, moderate-quality evidence). The mean differences (95% CI) in total and LDL cholesterol between the intervention and control arms were -0.61 mmol/L (95% CI -0.88 to -0.35, 11 trials, 6565 participants, low-quality evidence) and -0.70 mmol/L (95% CI -0.98 to -0.41, 12 trials, 7153 participants, moderate-quality evidence), respectively. There was a high degree of statistical heterogeneity in comparisons of blood pressure and lipids (I2 ≥ 80% for all) that could not be explained, so these results should be viewed with caution. Fixed-dose combination therapy improved adherence to a multidrug strategy by 44% (26% to 65%) compared with usual care (4 trials, 3835 participants, moderate-quality evidence). AUTHORS' CONCLUSIONS: The effects of fixed-dose combination therapy on all-cause mortality or ASCVD events are uncertain. A limited number of trials reported these outcomes, and the included trials were primarily designed to observe changes in ASCVD risk factor levels rather than clinical events, which may partially explain the observed differences in risk factors that were not translated into differences in clinical outcomes among the included trials. Fixed-dose combination therapy is associated with modest increases in adverse events compared with placebo, active comparator, or usual care but may be associated with improved adherence to a multidrug regimen. Ongoing, longer-term trials of fixed-dose combination therapy will help demonstrate whether short-term changes in risk factors might be maintained and lead to expected differences in clinical events based on these changes

    The influence of standards and clinical guidelines on prosthetic and orthotic service quality : a scoping review

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    OBJECTIVES: Standards and guidelines are an integral part of prosthetic and orthotic service delivery in the developed world underpinned by an assumption that they lead to improved services. Implementing them has a cost, however, and that cost needs to be justified, particularly in resource-limited environments. This scoping review thus asks the question, "What is the evidence of the impact of standards and guidelines on service delivery outcomes in prosthetics and orthotics?" MATERIALS AND METHODS: A structured search of three electronic databases (Medline, Scopus and Web of Science) followed by manual searching of title, abstract and full text, yielded 29 articles. RESULTS: Four categories of papers were identified: Descriptions and Commentaries (17 papers), Guideline Development (7), Guideline Testing (2) and Standards implementation (3). No articles were explicitly designed to assess the impact of standards and guidelines on service delivery outcomes in prosthetics and orthotics. DISCUSSION AND CONCLUSION: Studies tended to be commentaries on or descriptions of guideline development, testing or implementation of standards. The literature is not sufficiently well developed to warrant the cost and effort of a systematic review. Future primary research should seek to demonstrate whether and how guidelines and standards improve the outcomes for people that require prostheses, orthoses and other assistive devices. Implications for Rehabilitation International Standards and Clinical Guidelines are now an integral part of clinical service provision in prosthetics and orthotics in the developed world. Complying with standards and guidelines has a cost and, particularly in resource-limited environments, it should be possible to justify this in terms of the resulting benefits. This scoping review concludes that there have been no previous studies designed to directly quantify the effects of implementing standards and guidelines on service delivery

    Guidelines for Family-Centered Care in the Neonatal, Pediatric, and Adult ICU.

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    OBJECTIVE: To provide clinicians with evidence-based strategies to optimize the support of the family of critically ill patients in the ICU. METHODS: We used the Council of Medical Specialty Societies principles for the development of clinical guidelines as the framework for guideline development. We assembled an international multidisciplinary team of 29 members with expertise in guideline development, evidence analysis, and family-centered care to revise the 2007 Clinical Practice Guidelines for support of the family in the patient-centered ICU. We conducted a scoping review of qualitative research that explored family-centered care in the ICU. Thematic analyses were conducted to support Population, Intervention, Comparison, Outcome question development. Patients and families validated the importance of interventions and outcomes. We then conducted a systematic review using the Grading of Recommendations, Assessment, Development and Evaluations methodology to make recommendations for practice. Recommendations were subjected to electronic voting with pre-established voting thresholds. No industry funding was associated with the guideline development. RESULTS: The scoping review yielded 683 qualitative studies; 228 were used for thematic analysis and Population, Intervention, Comparison, Outcome question development. The systematic review search yielded 4,158 reports after deduplication and 76 additional studies were added from alerts and hand searches; 238 studies met inclusion criteria. We made 23 recommendations from moderate, low, and very low level of evidence on the topics of: communication with family members, family presence, family support, consultations and ICU team members, and operational and environmental issues. We provide recommendations for future research and work-tools to support translation of the recommendations into practice. CONCLUSIONS: These guidelines identify the evidence base for best practices for family-centered care in the ICU. All recommendations were weak, highlighting the relative nascency of this field of research and the importance of future research to identify the most effective interventions to improve this important aspect of ICU care

    Fixed-dose combination therapy for the prevention of atherosclerotic cardiovascular diseases

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    Background Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death and disability worldwide, yet ASCVD risk factor control and secondary prevention rates remain low. A fixed‐dose combination of blood pressure‐ and cholesterol‐lowering and antiplatelet treatments into a single pill, or polypill, has been proposed as one strategy to reduce the global burden of ASCVD. Objectives To determine the effect of fixed‐dose combination therapy on all‐cause mortality, fatal and non‐fatal ASCVD events, and adverse events. We also sought to determine the effect of fixed‐dose combination therapy on blood pressure, lipids, adherence, discontinuation rates, health‐related quality of life, and costs. Search methods We updated our previous searches in September 2016 of CENTRAL, MEDLINE, Embase, ISI Web of Science, and DARE, HTA, and HEED. We also searched two clinical trials registers in September 2016. We used no language restrictions. Selection criteria We included randomised controlled trials of a fixed‐dose combination therapy including at least one blood pressure‐lowering and one lipid‐lowering component versus usual care, placebo, or an active drug comparator for any treatment duration in adults 18 years old or older, with no restrictions on presence or absence of pre‐existing ASCVD. Data collection and analysis Three review authors independently selected studies for inclusion and extracted the data for this update. We evaluated risk of bias using the Cochrane 'Risk of bias' assessment tool. We calculated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous data with 95% confidence intervals (CI) using fixed‐effect models when heterogeneity was low (I2 and#60; 50%) and random‐effects models when heterogeneity was high (I2 ≥ 50%). We used the GRADE approach to evaluate the quality of evidence. Main results In the initial review, we identified nine randomised controlled trials with a total of 7047 participants and four additional trials (n = 2012 participants; mean age range 62 to 63 years; 30% to 37% women) were included in this update. Eight of the 13 trials evaluated the effects of fixed‐dose combination (FDC) therapy in populations without prevalent ASCVD, and the median follow‐up ranged from six weeks to 23 months. More recent trials were generally larger with longer follow‐up and lower risk of bias. The main risk of bias was related to lack of blinding of participants and personnel, which was inherent to the intervention. Compared with the comparator groups (placebo, usual care, or active drug comparator), the effects of the fixed‐dose combination treatment on mortality (FDC = 1.0% versus control = 1.0%, RR 1.10, 95% CI 0.64 to 1.89, I2 = 0%, 5 studies, N = 5300) and fatal and non‐fatal ASCVD events (FDC = 4.7% versus control = 3.7%, RR 1.26, 95% CI 0.95 to 1.66, I2 = 0%, 6 studies, N = 4517) were uncertain (low‐quality evidence). The low event rates for these outcomes and indirectness of evidence for comparing fixed‐dose combination to usual care versus individual drugs suggest that these results should be viewed with caution. Adverse events were common in both the intervention (32%) and comparator (27%) groups, with participants randomised to fixed‐dose combination therapy being 16% (RR 1.16, 95% CI 1.09 to 1.25, 11 studies, 6906 participants, moderate‐quality evidence) more likely to report an adverse event . The mean differences in systolic blood pressure between the intervention and control arms was ‐6.34 mmHg (95% CI ‐9.03 to ‐3.64, 13 trials, 7638 participants, moderate‐quality evidence). The mean differences (95% CI) in total and LDL cholesterol between the intervention and control arms were ‐0.61 mmol/L (95% CI ‐0.88 to ‐0.35, 11 trials, 6565 participants, low‐quality evidence) and ‐0.70 mmol/L (95% CI ‐0.98 to ‐0.41, 12 trials, 7153 participants, moderate‐quality evidence), respectively. There was a high degree of statistical heterogeneity in comparisons of blood pressure and lipids (I2 ≥ 80% for all) that could not be explained, so these results should be viewed with caution. Fixed‐dose combination therapy improved adherence to a multidrug strategy by 44% (26% to 65%) compared with usual care (4 trials, 3835 participants, moderate‐quality evidence). Authors' conclusions The effects of fixed‐dose combination therapy on all‐cause mortality or ASCVD events are uncertain. A limited number of trials reported these outcomes, and the included trials were primarily designed to observe changes in ASCVD risk factor levels rather than clinical events, which may partially explain the observed differences in risk factors that were not translated into differences in clinical outcomes among the included trials. Fixed‐dose combination therapy is associated with modest increases in adverse events compared with placebo, active comparator, or usual care but may be associated with improved adherence to a multidrug regimen. Ongoing, longer‐term trials of fixed‐dose combination therapy will help demonstrate whether short‐term changes in risk factors might be maintained and lead to expected differences in clinical events based on these changes

    Fixed-dose combination therapy for the prevention of atherosclerotic cardiovascular diseases

    No full text
    Background Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death and disability worldwide, yet ASCVD risk factor control and secondary prevention rates remain low. A fixed‐dose combination of blood pressure‐ and cholesterol‐lowering and antiplatelet treatments into a single pill, or polypill, has been proposed as one strategy to reduce the global burden of ASCVD. Objectives To determine the effect of fixed‐dose combination therapy on all‐cause mortality, fatal and non‐fatal ASCVD events, and adverse events. We also sought to determine the effect of fixed‐dose combination therapy on blood pressure, lipids, adherence, discontinuation rates, health‐related quality of life, and costs. Search methods We updated our previous searches in September 2016 of CENTRAL, MEDLINE, Embase, ISI Web of Science, and DARE, HTA, and HEED. We also searched two clinical trials registers in September 2016. We used no language restrictions. Selection criteria We included randomised controlled trials of a fixed‐dose combination therapy including at least one blood pressure‐lowering and one lipid‐lowering component versus usual care, placebo, or an active drug comparator for any treatment duration in adults 18 years old or older, with no restrictions on presence or absence of pre‐existing ASCVD. Data collection and analysis Three review authors independently selected studies for inclusion and extracted the data for this update. We evaluated risk of bias using the Cochrane 'Risk of bias' assessment tool. We calculated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous data with 95% confidence intervals (CI) using fixed‐effect models when heterogeneity was low (I2 &lt; 50%) and random‐effects models when heterogeneity was high (I2 ≥ 50%). We used the GRADE approach to evaluate the quality of evidence. Main results In the initial review, we identified nine randomised controlled trials with a total of 7047 participants and four additional trials (n = 2012 participants; mean age range 62 to 63 years; 30% to 37% women) were included in this update. Eight of the 13 trials evaluated the effects of fixed‐dose combination (FDC) therapy in populations without prevalent ASCVD, and the median follow‐up ranged from six weeks to 23 months. More recent trials were generally larger with longer follow‐up and lower risk of bias. The main risk of bias was related to lack of blinding of participants and personnel, which was inherent to the intervention. Compared with the comparator groups (placebo, usual care, or active drug comparator), the effects of the fixed‐dose combination treatment on mortality (FDC = 1.0% versus control = 1.0%, RR 1.10, 95% CI 0.64 to 1.89, I2 = 0%, 5 studies, N = 5300) and fatal and non‐fatal ASCVD events (FDC = 4.7% versus control = 3.7%, RR 1.26, 95% CI 0.95 to 1.66, I2 = 0%, 6 studies, N = 4517) were uncertain (low‐quality evidence). The low event rates for these outcomes and indirectness of evidence for comparing fixed‐dose combination to usual care versus individual drugs suggest that these results should be viewed with caution. Adverse events were common in both the intervention (32%) and comparator (27%) groups, with participants randomised to fixed‐dose combination therapy being 16% (RR 1.16, 95% CI 1.09 to 1.25, 11 studies, 6906 participants, moderate‐quality evidence) more likely to report an adverse event . The mean differences in systolic blood pressure between the intervention and control arms was ‐6.34 mmHg (95% CI ‐9.03 to ‐3.64, 13 trials, 7638 participants, moderate‐quality evidence). The mean differences (95% CI) in total and LDL cholesterol between the intervention and control arms were ‐0.61 mmol/L (95% CI ‐0.88 to ‐0.35, 11 trials, 6565 participants, low‐quality evidence) and ‐0.70 mmol/L (95% CI ‐0.98 to ‐0.41, 12 trials, 7153 participants, moderate‐quality evidence), respectively. There was a high degree of statistical heterogeneity in comparisons of blood pressure and lipids (I2 ≥ 80% for all) that could not be explained, so these results should be viewed with caution. Fixed‐dose combination therapy improved adherence to a multidrug strategy by 44% (26% to 65%) compared with usual care (4 trials, 3835 participants, moderate‐quality evidence). Authors' conclusions The effects of fixed‐dose combination therapy on all‐cause mortality or ASCVD events are uncertain. A limited number of trials reported these outcomes, and the included trials were primarily designed to observe changes in ASCVD risk factor levels rather than clinical events, which may partially explain the observed differences in risk factors that were not translated into differences in clinical outcomes among the included trials. Fixed‐dose combination therapy is associated with modest increases in adverse events compared with placebo, active comparator, or usual care but may be associated with improved adherence to a multidrug regimen. Ongoing, longer‐term trials of fixed‐dose combination therapy will help demonstrate whether short‐term changes in risk factors might be maintained and lead to expected differences in clinical events based on these changes

    Fixed-dose combination therapy for the prevention of cardiovascular disease

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    BACKGROUND: Cardiovascular disease (CVD) is the leading cause of death and disability worldwide, yet CVD risk factor control and secondary prevention rates remain low. A fixed-dose combination of blood pressure and cholesterol lowering and antiplatelet treatments into a single pill, or polypill, has been proposed as one strategy to reduce the global burden of CVD by up to 80% given its potential for better adherence and lower costs. OBJECTIVES: To determine the effectiveness of fixed-dose combination therapy on reducing fatal and non-fatal CVD events and on improving blood pressure and lipid CVD risk factors for both primary and secondary prevention of CVD. We also aimed to determine discontinuation rates, adverse events, health-related quality of life, and costs of fixed-dose combination therapy. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2013, Issue 6), MEDLINE Ovid (1946 to week 2 July 2013), EMBASE Ovid (1980 to Week 28 2013), ISI Web of Science (1970 to 19 July 2013), and the Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment Database (HTA), and Health Economics Evaluations Database (HEED) (2011, Issue 4) in The Cochrane Library. We used no language restrictions. SELECTION CRITERIA: We included randomised controlled trials of a fixed-dose combination therapy including at least one blood pressure lowering and one lipid lowering component versus usual care, placebo, or a single drug active component for any treatment duration in adults ≥ 18 years old with no restrictions on presence or absence of pre-existing cardiovascular disease. DATA COLLECTION AND ANALYSIS: Three review authors independently selected studies for inclusion and extracted the data. We evaluated risk of bias using the Cochrane risk of bias assessment tool. We sought to include outcome data on all-cause mortality, fatal and non-fatal CVD events, adverse events, changes in systolic and diastolic blood pressure, total and low density lipoprotein (LDL) cholesterol concentrations, discontinuation rates, quality of life, and costs. We calculated risk ratios (RR) for dichotomous data and weighted mean differences (MD) for continuous data with 95% confidence intervals (CI) using fixed-effect models when heterogeneity was low (I(2) 50%). MAIN RESULTS: We found nine randomised controlled trials with a total of 7047 participants. Seven of the nine trials evaluated the effects of fixed-dose combination therapy on primary CVD prevention, and the trial length ranged from six weeks to 15 months. We found a moderate to high risk of bias in the domains of selection, performance, detection, attrition, and other types of bias in five of the nine trials. Compared with the comparator groups, the effects of the fixed-dose combination treatment on mortality (1.2% versus 1.0%, RR 1.26, 95% CI 0.67 to 2.38,  N = 3465) and cardiovascular events (4.0% versus 2.9%, RR 1.38, 95% CI 0.91 to 2.10, N = 2479) were uncertain (low quality evidence). The low event rates for these outcomes, limited availability of data as only two out of nine trials reported on these outcomes, and a high risk of bias in at least one domain suggest that these results should not be viewed with confidence. Adverse events were common in both the intervention (30%) and comparator (24%) groups, with participants randomised to fixed-dose combination therapy being 20% (95% CI 9% to 30%) more likely to report an adverse event. Notably, no serious adverse events were reported. Compared with placebo, the rate of discontinuation among participants randomised to fixed-dose combination was higher (14% versus 11%, RR 1.26 95% CI 1.02 to 1.55). The weighted mean differences in systolic and diastolic blood pressure between the intervention and control arms were -7.05 mmHg (95% CI -10.18 to -3.87) and -3.65 mmHg (95% CI -5.44 to -1.85), respectively. The weighted mean differences (95% CI) in total and LDL cholesterol between the intervention and control arms were -0.75 mmol/L (95% CI -1.05 to -0.46) and -0.81 mmol/L (95% CI -1.09 to -0.53), respectively. There was a high degree of statistical heterogeneity in comparisons of blood pressure and lipids (I(2) ≥ 70% for all) that could not be explained, so these results should be viewed with caution. Fixed-dose combination therapy improved adherence to a multi-drug strategy by 33% (26% to 41%) compared with usual care, but this comparison was reported in only one study. The effects of fixed-dose combination therapy on quality of life are uncertain, though these results were reported in only one trial. No trials reported costs. AUTHORS' CONCLUSIONS: Compared with placebo, single drug active component, or usual care, the effects of fixed-dose combination therapy on all-cause mortality or CVD events are uncertain; only few trials report these outcomes and the included trials were primarily designed to observe changes in CVD risk factor levels rather than clinical events. Reductions in blood pressure and lipid parameters are generally lower than those previously projected, though substantial heterogeneity of results exists. Fixed-dose combination therapy is associated with modest increases in adverse events compared with placebo, single drug active component, or usual care but may be associated with improved adherence to a multidrug regimen. Ongoing trials of fixed-dose combination therapy will likely inform key outcomes

    Secondhand smoke (SHS) exposure is associated with circulating markers of inflammation and endothelial function in adult men and women

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    AIMS: Secondhand smoke (SHS) exposure is associated with elevated CHD risks. Yet the pathways through which this may operate have not been investigated in epidemiologic studies with objective SHS exposure measures and a wide range of CHD risk factors associated with active smoking. Therefore we investigate associations between SHS exposure and CHD risk factors, to clarify how SHS exposure may raise risk of CHD. METHODS: Cross-sectional population-based study of 5029 men and women aged 59-80 years from primary care practices in Great Britain. Smoking, behavioural and demographic information was reported in questionnaires; nurses made physical measurements and took blood samples for analysis of serum cotinine and markers of inflammation, hemostasis and endothelial dysfunction. RESULTS: Active cigarette smokers had lower albumin and higher triglycerides, CRP, IL-6, white cell count, fibrinogen, blood viscosity, factor VIII, VWF and t-PA than non-smokers. Among non-smokers, serum cotinine levels were independently positively associated with CRP, fibrinogen, factor VIII, VWF and t-PA and inversely associated with albumin, after adjustment for age, gender, social and behavioural factors. The differences in CRP, fibrinogen and albumin between cotinine 0.7ng/ml were one-third to one half the size of differences between cotinine </=0.05ng/ml and current smokers, but were of similar magnitude for VWF and t-PA. CONCLUSIONS: Endothelial, inflammatory and haemostatic markers related to CHD risk showed independent associations with SHS exposure in the same direction as those for active smoking. Results aid understanding of the associations between SHS exposure and elevated CHD risks
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