Is smokeless tobacco a risk factor for coronary heart disease? A systematic review of epidemiological studies

Prevalence and Correlates of Snuff Use, and its Association With Tuberculosis, Among Women Living With HIV in South Africa

INTRODUCTION

A higher proportion of people living with HIV (PLWH) smoke compared to the general population, but little information exists about the prevalence and correlates of smokeless tobacco use among PLWH. In South Africa, dry powdered tobacco is inhaled nasally as snuff.

METHODS

A cross-sectional survey among PLWH attending three HIV clinics was conducted. Snuff use was assessed via self-report and urine cotinine.

RESULTS

Given the low (3%) prevalence of snuff use among men, analysis was restricted to n = 606 nonsmoking women living with HIV. Half (n = 298, 49%) were snuff users, the majority of whom (n = 244, 84%) had a positive urine cotinine test. In adjusted analysis, snuff use was negatively associated with higher education (relative risk [RR] 0.55; 95% confidence interval [CI]: 0.39, 0.77) and mobile phone ownership (RR 0.83; 95% CI: 0.71, 0.98), and positively associated with ever having tuberculosis (TB) (RR 1.22; 95% CI: 1.03, 1.45). In adjusted analysis, with current TB as the outcome, snuff use was marginally statistically significantly associated with a twofold increase in odds of a current TB diagnosis (odds ratio [OR] 1.99; 95% CI: 0.98, 4.15).

DISCUSSION

A high proportion of nonsmoking South African women living with HIV use snuff, which was a risk factor for TB. Additional research is needed to understand the relationship between snuff, TB, and other potential health risks.

IMPLICATIONS

PLWH have a higher prevalence of smoking than their seronegative peers, but there is a paucity of research on smokeless tobacco use in this population, especially in low-resource settings. TB is the leading cause of death among PLWH, and with improvements to HIV treatment and care, PLWH are at greater risk of tobacco-related diseases. We report an extremely high prevalence of snuff use among women living with HIV in South Africa. Further, in this population snuff use is positively associated with ever having a TB diagnosis, as well as currently having TB.

Financial Conflicts of Interest and Stance on Tobacco Harm Reduction: A Systematic Review

Background. Tobacco companies have actively promoted the substitution of cigarettes with purportedly safer tobacco products (e.g., smokeless tobacco, e-cigarettes) as tobacco harm reduction (THR). Given the tobacco, e-cigarette, and pharmaceutical industries' substantial financial interests, we quantified industry influence on support for THR. Objectives. To analyze a comprehensive set of articles published in peer-reviewed journals assessing funding sources and support for or opposition to substitution of tobacco or nicotine products as harm reduction. Search Methods. We searched PubMed, Embase, Web of Science, and PsycINFO with a comprehensive search string including all articles, comments, and editorials published between January 1, 1992, and July 26, 2016. Selection Criteria. We included English-language publications published in peer-reviewed journals addressing THR in humans and excluded studies on modified cigarettes, on South Asian smokeless tobacco variants, on pregnant women, on animals, not mentioning a tobacco or nicotine product, on US Food and Drug Administration-approved nicotine replacement therapies, and on nicotine vaccines. Data Collection and Analysis. We double-coded all articles for article type; primary product type (e.g., snus, e-cigarettes); themes for and against THR; stance on THR; THR concepts; funding or affiliation with tobacco, e-cigarette, pharmaceutical industry, or multiple industries; and each author's country. We fit exact logistic regression models with stance on THR as the outcome (pro- vs anti-THR) and source of funding or industry affiliation as the predictor taking into account sparse data. Additional models included article type as the outcome (nonempirical or empirical) and industry funding or affiliation as predictor, and stratified analyses for empirical and nonempirical studies with stance on THR as outcome and funding source as predictor. Main Results. Searches retrieved 826 articles, including nonempirical articles (21%), letters or commentaries (34%), editorials (5%), cross-sectional studies (15%), systematic reviews and meta-analyses (3%), and randomized controlled trials (2%). Overall, 23.9% disclosed support by industry; 49% of articles endorsed THR, 42% opposed it, and 9% took neutral or mixed positions. Support from the e-cigarette industry (odds ratio [OR] = 20.9; 95% confidence interval [CI] = 5.3, 180.7), tobacco industry (OR = 59.4; 95% CI = 10.1, +infinity), or pharmaceutical industry (OR = 2.18; 95% CI = 1.3, 3.7) was significantly associated with supportive stance on THR in analyses accounting for sparse data. Authors' Conclusions. Non-industry-funded articles were evenly divided in stance, while industry-funded articles favored THR. Because of their quantity, letters and comments may influence perceptions of THR when empirical studies lack consensus. Public Health Implications. Public health practitioners and researchers need to account for industry funding when interpreting the evidence in THR debates.

Stable Angina Medical Therapy Management Guidelines: A Critical Review of Guidelines from the European Society of Cardiology and National Institute for Health and Care Excellence

Most patients with stable angina can be managed with lifestyle changes, especially smoking cessation and regular exercise, along with taking antianginal drugs. Randomised controlled trials show that antianginal drugs are equally effective and none of them reduced mortality or the risk of MI, yet guidelines prefer the use of beta-blockers and calcium channel blockers as a first-line treatment. The European Society of Cardiology guidelines for the management of stable coronary artery disease provide classes of recommendation with levels of evidence that are well defined. The National Institute for Health and Care Excellence (NICE) guidelines for the management of stable angina provide guidelines based on cost and effectiveness using the terms first-line and second-line therapy. Both guidelines recommend using low-dose aspirin and statins as disease-modifying agents. The aim of this article is to critically appraise the guidelines’ pharmacological recommendations for managing patients with stable angina.

Relationships Among Chewing Tobacco, Cigarette Smoking, and Chronic Health Conditions in Males 18-44 Years of Age

As more public places are designated "non-smoking," chewing tobacco could be an alternative choice for tobacco use; however, controversy exists over the long-term health effects associated with it. This study assessed the relationship between chewing tobacco, cigarette smoking, and chronic health conditions in a representative sample of males 18-44 years of age, while controlling for other variables known to be related to tobacco use. This cross sectional analysis used 2013 data from the Behavioral Risk Factor Surveillance System (BRFSS). The results indicated that about 41% of males reported one or more chronic health conditions, and that about 15% used chewing tobacco only, 21% smoked cigarettes only, and 6% did both. From adjusted analyses, those who chewed tobacco only were 49% more likely to report one or more health conditions; those who smoked cigarettes only were 34% more likely to report one or more health conditions; and those who did both were 95% more likely to report at least one health condition. Overall, any combination of tobacco use was significantly and similarly related to the increased prevalence of chronic health conditions in males aged 18-44 years. Although chewing tobacco use may not be as prevalent in the general population as cigarette smoking, clinicians should be aware of the similar health risks associated with all tobacco use at ages younger than may be expected, and encourage cessation of any tobacco use.

Association between iq'mik smokeless tobacco use and cardiometabolic risk profile among Yup'ik Alaska Native people

OBJECTIVE

The traditional lifestyle of Yup'ik Alaska Native people, including a diet abundant in marine-based foods and physical activity, may be cardio-protective. However, iq'mik, a traditional form of smokeless tobacco used by >50% of Yup'ik adults, could increase cardiometabolic (CM) risk. Our objective was to characterize the associations between iq'mik use and biomarkers of CM status (low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], triglycerides [TG], systolic blood pressure [SBP] and diastolic blood pressure [DBP], glycated hemoglobin [HbA1c], fasting blood glucose [FBG], waist circumference [WC], and body mass index [BMI]).

DESIGN

We assessed these associations using data from a cross-sectional sample of Yup'ik adults (n = 874). Current iq'mik use, demographic, and lifestyle data were collected through interviews. Fasting blood samples were collected to measure LDL-C, HDL-C, TG, HbA1c, and FBG. SBP, DBP, WC, and BMI were obtained by physical examination. We characterized the association between current iq'mik use and continuous biomarkers of CM status using multiple approaches, including adjustment for measures of Yup'ik lifestyle and a propensity score.

RESULTS

Based on either adjustment method, current iq'mik use was significantly and positively associated with at least 5% higher HDL-C, and significantly associated but in an inverse direction with multiple biomarkers of CM status including 7% lower TG, 0.05% lower HbA1c, 2% lower FBG, 4% lower WC, and 4% lower BMI. Observed associations for LDL-C, SBP, and DBP varied by adjustment method.

CONCLUSIONS

This inverse association between iq'mik use and cardiometabolic risk status has not been previously reported. Additional research is needed to replicate these findings and explore physiological mechanisms and/or confounding factors.

Socio-demographic and behavioural determinants of body mass index among an adult population in rural Northern Ghana: the AWI-Gen study

BACKGROUND

Obesity and associated cardiometabolic diseases are increasing in urban sub-Saharan Africa due to a complex epidemiological and nutritional transition. Related data on rural communities is scarce.

OBJECTIVES

The study characterized the socio-demographic and behavioural factors influencing body mass index (BMI) among adults in rural Northern Ghana Methods: A population-based cross-sectional study involving adults aged 40-60 years residing in the Kassena-Nankana districts was undertaken. Demographic, socio-economic and behavioural data were collected along with measures of anthropometry. We determined factors associated with BMI among women and men.

RESULTS

A total of 2014 adults were studied. The median age was 51 (IQR 45-57) years and 54% were women. The prevalence of overweight/obesity was higher among women than men (18.4% vs. 7.2%; p < 0.001), whilst underweight was more prevalent in men (18.3% vs. 13.1%; p = 0.001). Participants with the highest level of education and a high household socio-economic status had higher BMIs than those in the lowest strata in both men (β = 0.074, p = 0.028 and β = 0.072, p < 0.001, respectively) and women (β = 0.174, p = 0.001 and β = 0.109, p < 0.001, respectively). Men (β = -0.050; p < 0.001) and women (β = -0.073; p < 0.001) of the Nankana ethnic group had a lower BMI than the Kassena ethnic group. Among men, alcohol consumption (β = -0.021; p = 0.001) and smoking (β = -0.216; p < 0.001) were associated with lower BMI. Smokeless tobacco was associated with lower BMI among women. Pesticide exposure was associated with higher BMI (β = 0.022; p = 0.022) among men.

CONCLUSION

Age, sex, ethno-linguistic group and prevailing socio-demographic and behavioural factors within this rural community in Northern Ghana influence BMI. The observed positive association between pesticide use and BMI warrants further investigation.

Global burden of all-cause and cause-specific mortality due to smokeless tobacco use: systematic review and meta-analysis

OBJECTIVES

To systematically review and meta-analyse the studies investigating the association between smokeless tobacco (SLT) use and all-cause mortality and cause-specific mortality outcomes among adult users of SLT and estimate the number of attributable deaths worldwide.

METHODS

Random-effects meta-analysis was used to estimate the pooled risk of death due to SLT use. Population attributable fractions were derived and used to calculate the number of attributable deaths. Observational studies published upto 2015 were identified through MEDLINE, IndMED, Google Scholar and other databases. Data on the prevalence of SLT use was obtained from latest reports or national surveys. Data on the disease burden were obtained from the Global Burden of Disease Study. Hospital-based or community-based case-control and cohort studies that adjusted for the smoking status were included.

RESULTS

16 studies that provided estimates for mortality due to all cause, all cancer, upper aerodigestive tract (UADT) cancer, stomach cancer, cervical cancer, ischaemic heart disease (IHD) and stroke were included. A significant association was found for mortality due to all cause (1.22; 1.11-1.34), all cancer (1.31; 1.16-1.47), UADT cancer (2.17; 1.47-3.22), stomach cancer (1.33; 1.12-1.59), cervical cancer (2.07; 1.64-2.61), IHD (1.10; 1.04-1.17) and stroke (1.37; 1.24-1.51). Subgroup analysis showed major regional differences. Globally, the number of attributable deaths from all-cause mortality was 652 494 (234 008-1 081 437), of which 88% was borne by the South-East Asian region.

CONCLUSIONS

SLT is responsible for a large number of deaths worldwide with the South-East Asian region bearing a substantial share of the burden.

Smokeless tobacco and coronary heart disease: a 12-year follow-up study

Background Cigarette smoking has declined whereas the use of smokeless tobacco is increasing. There is an ongoing debate as to whether smokeless tobacco is a recommendable strategy to help smokers to quit. However, very few studies have examined the association between smokeless tobacco, namely snuff, and coronary heart disease, which implies that it has not been possible to provide scientific results for public health policies and clinical guidelines concerning the use of smokeless tobacco.

Design A follow-up study.

Methods A random sample of 3120 healthy men aged 30–74 years was interviewed in 1988 and 1989 and followed up to the year 2000 with regard to coronary heart disease. Cox regression was used to estimate the relative risk of coronary heart disease in six categories of smoking and snuffing habits, after adjustment for established risk factors for coronary heart disease.

Results Smokers, former smokers, and those who combined smoking and snuffing had significantly higher hazard ratios than never-smokers. The very highest hazard ratio was found among individuals combining smoking and snuffing. Daily snuffers had a hazard ratio of 1.62 (95% confidence interval 0.70–3.03) after adjustment for age.

Conclusions Even though the association between daily snuffing and coronary heart disease was non-significant, the hazard ratio was markedly increased. Therefore, smokers should not use smokeless tobacco in order to quit smoking, especially as safer alternatives are available. Further studies in different settings are required to provide scientific results for public health policies and clinical guidelines.

Non-Smoking Tobacco Affects Endothelial Function in Healthy Men in One of the Largest Health Studies Ever Performed; The Nord-Trøndelag Health Study in Norway; HUNT3

BACKGROUND

Oral tobacco (snuff) is taking a large market share in Scandinavia, especially with young users. However, long-term health effects are unknown. Small studies show association between snuff and reduced endothelial function, representing an early stage of vascular injury that often precedes manifest cardiovascular disease by several years. We therefore determined the associations between snuff and endothelial function in a large sample of healthy Norwegian men.

METHODS AND DESIGN

In the Fitness substudy of the Nord-Trøndelag Health Study (HUNT3), endothelial function was measured by flow-mediated dilation (FMD). Aerobic fitness was measured by peak oxygen uptake (VO2peak). A cross-sectional design including 1 592 self-reported healthy men compared these observations with records of present tobacco use, standard cardiovascular risk factors, and socioeconomic status, using general linear models.

RESULTS

FMD was lower in snuff users (FMD: 4.12%, 3.63, 4.61) compared to non-users (FMD: 4.52%, 4.27, 4.78) after adjustment for age (difference: -0.57%, -1.12, -0.01). After further adjustment for potential confounders, FMD still tended to be lower in snuff users than in non-users (difference: -0.53%, -1.09, 0.02). This difference was even more pronounced in the inactive snuff users (-0.83%, -1.59, -0.06) and in the low fit snuff users (-0.74%, CI -0.55, 0.079).

CONCLUSIONS

Oral tobacco is associated with a tendency towards reduced endothelial function, indicating vascular changes that precede cardiovascular disease. The strongest associations were found in men with low physical activity or reduced aerobic fitness.

Nicotine lozenges and behavioural interventions may help smokeless tobacco users to quit

DATA SOURCES

Cochrane Central Register of Controlled trials (CENTRAL); Medline; Embase; PsycINFO. Additional sources were also searched for early versions of the review: Web of Science, Dissertation Abstracts Online, Scopus, Healthstar, ERIC, National Technical Information Service database and Current Contents.

STUDY SELECTION

Randomised controlled trials and pseudo-randomised controlled trials allocating smokeless tobacco (ST) users to an intervention or control, or to different interventions. Interventions could be pharmacological (ie nicotine replacement therapy (NRT), bupropion, varenicline) or behavioural, and could be directed at individual ST users or at groups of users.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data about participants, interventions, outcomes and methodological quality. Any discrepancies in extracted data were resolved by consensus. Synthesis followed standard Cochrane methodology.

RESULTS

Thirty-four trials were included, 32 from the USA, one from Sweden and one from Sweden and Norway. Sixteen of the trials assessed pharmacological interventions and 19 assessed behavioural interventions (two studies did both). Varenicline increased ST abstinence rates (risk ratio 1.34, 95% confidence interval (CI) 1.08-1.68). Bupropion did not show a benefit of treatment. Neither nicotine patch nor nicotine gum increased abstinence. Nicotine lozenges did increase tobacco abstinence (RR 1.36, 95% CI 1.17-1.59). Behvaioural interventions resulted in a RR of 1.39 (95% CI 1.25-1.55) for those already motivated to quit and 1.37 (95% CI 1.23-1.53) for anyone.

CONCLUSIONS

Varenicline, nicotine lozenges and behavioural interventions may help ST users to quit. Confidence in results for nicotine lozenges is limited. Confidence in the size of effect from behavioural interventions is limited because the components of behavioural interventions that contribute to their impact are not clear.

A systematic review of transitions between cigarette and smokeless tobacco product use in the United States

Background

Smokeless tobacco use is becoming an increasingly important public health issue in the US and may influence cigarette smoking behavior. Systematic information on transitions between smokeless tobacco and cigarette use in the US is limited.

Methods

We conducted a systematic review of published literature on transitions between smokeless tobacco and cigarette use in the US. We searched PubMed, Web of Science and EbscoHost databases for all published articles from January 2000 to March 2014 that presented estimates of transitions in US youth and adult study populations over time between at least one of the following tobacco use states: exclusive cigarette smoking, exclusive smokeless tobacco use, dual use of both products, and use of neither product. We excluded non-English language studies, studies published before 2000, clinical trials, controlled cessation programs, and clinical studies or evaluations of smokeless tobacco cessation programs.

Results

The review identified six studies on US populations published since 2000 with longitudinal data on some or all of the transitions that users can undergo between smokeless tobacco and cigarette use. There was considerable heterogeneity across studies in design and tobacco use definitions. Despite these differences, the existing data indicate that switching behaviors from exclusive smoking to exclusive smokeless tobacco use are limited (adults: 0%-1.4%, adolescents: 0.8%-3.8%) but may be more common from exclusive smokeless tobacco use to exclusive smoking (adults: 0.9%-26.6%, adolescents: 16.6%-25.5%). Among adults, exclusive cigarette smoking was generally stable and consistent (79.7% to 87.6%) over follow-up across studies but less stable in adolescents (46.8%-78.7%). Exclusive smokeless tobacco use was less stable than exclusive cigarette smoking over time (adults: 59.4%-76.6%, adolescents: 26.2%-44.8%).

Conclusion

This review provides published estimates of the proportions of adults and adolescents transitioning between tobacco use categories from the most recently available studies on longitudinal transitions between smokeless tobacco and cigarettes in the US. These data can be used to track tobacco use behaviors and evaluate their effect on public health; however, the data for these studies were generally collected more than a decade ago. Additional research including nationally representative longitudinal estimates using consistent definitions and designs, would improve understanding of current tobacco transition behaviors.

The impact of product information and trials on demand for smokeless tobacco and cigarettes: evidence from experimental auctions

INTRODUCTION

Epidemiological and toxicological evidence suggests lower risk of smokeless tobacco (ST) products compared to cigarettes. Less is known, however, about consumer perceptions and use of novel forms of ST, including snus and dissolvable tobacco.

METHODS

In this study, we conducted in-person experimental auctions in Buffalo, NY, Columbia, SC, and Selinsgrove, PA with 571 smokers to test the impact of information and product trials on smokers' preferences. Auctions were conducted between November 2010-November 2011.

RESULTS

We found no evidence of an impact of product trials on demand in our auctions. Anti-ST information increased demand for cigarettes when presented alone, but when presented with pro-ST information it decreased demand for cigarettes. It did not decrease demand for ST products. Anti-smoking information increased demand for ST products, but did not affect cigarette demand.

CONCLUSIONS

These findings suggest that credible and effective communications about tobacco harm reduction should reinforce the negative effects of smoking.

Association between betel quid chewing and carotid intima-media thickness in rural Bangladesh

BACKGROUND

Areca nut, more commonly known as betel nut, is the fourth most commonly used addictive substance in the world. Though recent evidence suggests it may play a role in the development of cardiovascular disease, no studies have investigated whether betel nut use is related to subclinical atherosclerosis.

METHODS

We evaluated the association between betel nut use and subclinical atherosclerosis in 1206 participants randomly sampled from the Health Effects of Arsenic Longitudinal Study (HEALS). Frequency and duration of betel nut use were assessed at baseline, and carotid IMT was measured on average 6.65 years after baseline.

RESULTS

A positive association was observed between duration and cumulative exposure (function of duration and frequency) of betel nut use and IMT, with above-median use for duration (7 or more years) and cumulative exposure (30 or more quid-years) corresponding to a 19.1 μm [95% confidence interval (CI): 5.3-32.8; P ≤ 0.01] and 16.8 μm (95% CI: 2.9-30.8; P < 0.05) higher IMT in an adjusted model, respectively. This association was more pronounced in men [32.8 μm (95% CI: 10.0-55.7) and 30.9 μm (95% CI: 7.4-54.2)]. There was a synergy between cigarette smoking and above-median betel use such that the joint exposure was associated with a 42.4 μm (95% CI: 21.6-63.2; P ≤ 0.01) difference in IMT.

CONCLUSION

Betel nut use at long duration or high cumulative exposure levels is associated with subclinical atherosclerosis as manifested through carotid IMT. This effect is especially pronounced among men and cigarette smokers.

Effect of smoking status on healthcare costs and resource utilization in patients with type 2 diabetes in routine clinical practice: a retrospective nested case-control economic study

AIM

To compare healthcare resource utilization and costs according to smoking status in patients with type 2 diabetes in clinical practice.

METHODS

A retrospective cohort nested case-control study was designed. Cases were current smokers, while 2 types of controls (former smokers and never smokers) were matched (2 controls per case) for age, sex, duration of diabetes and burden of comorbidity using data from medical records. Noninstitutionalized diabetics of both genders, aged>18 years and seen consecutively over a 5-year period before the index date, were enrolled. Analysis compared healthcare resource utilization, loss of productivity due to sick leave and corresponding costs.

RESULTS

In total, 2,490 medical records were analyzed, i.e. 498 cases, 996 former smokers and 996 never smokers. Mean age was 63.4 years (64.9% male). Smokers had higher glycosylated hemoglobin levels (7.4 vs. 7.2 and 7.2%, respectively; p=0.013) and a lower degree of metabolic control (49.2 vs. 54.7 and 55.8%; p=0.036). Smokers had higher average annual costs (EUR 3,583) than former smokers (EUR 2,885; p<0.001) and never smokers (EUR 2,183; p<0.001).

CONCLUSIONS

Diabetic smoker patients had lower metabolic control, higher health resource utilization and more sick leave, resulting in higher healthcare costs and lost productivity compared with both former and never smoker diabetics.

Cost and clinical consequences of smoking cessation in outpatients after cardiovascular disease: a retrospective cohort study

This cohort retrospective study explored the cost and clinical consequences of smoking cessation in outpatients after cardiovascular events (CVEs), in Spain. A total of 2,540 patients (68.1 years; 60.7% male; 8.4% smokers, 52.9% ex-smokers, and 38.7% never smokers) fulfilling the selection criteria and followed up throughout a period of 36 months after the event were considered eligible for analysis. Total costs were higher among current smokers in comparison with ex-smokers and never smokers (€7,981 versus [vs] €7,322 and €5,619, respectively) (P < 0.001). Both health care costs (€6,273 vs €5,673 and €4,823, respectively) (P < 001) and loss of productivity at work costs (€1,708 vs €1,650 and €796, respectively) (P < 001) accounted for such differences. There was also a difference in CVE recurrence rates (18.6% vs 16.5% and 9.6%, respectively) (P < 01). Smoking cessation in CVE outpatients was associated with lower cost and risk of CVE recurrence compared with smokers, and their health status was similar to that of never smokers, in routine clinical practice in Spain.

Smokeless tobacco and cardiovascular disease in low and middle income countries

Smoking is an important cardiovascular risk factor, however, use of smokeless tobacco has not been well studied. Smokeless tobacco use is high in countries of South and Southeast Asia, Africa and Northern Europe. Meta-analyses of prospective studies of smokeless tobacco users in Europe reported a relative risk for fatal coronary heart disease of 1.13 (confidence intervals 1.06-1.21) and fatal stroke of 1.40 (1.28-1.54) while in Asian countries it was 1.26 (1.12-1.40). Case-control studies reported significantly greater risk for acute coronary events in smokeless tobacco users (odds ratio 2.23, 1.41-3.52), which was lower than smokers (2.89, 2.11-3.96), and subjects who both chewed and smoked, had the greatest risk (4.09, 2.98-5.61). There is a greater prevalence of hypertension and metabolic syndrome in users of smokeless tobacco. Smokeless tobacco use leads to accelerated atherothrombosis similar to smoking. There is an urgent need for public health and clinical interventions to reduce smokeless tobacco addiction.

Second-hand tobacco smoke and cardiovascular disease risk: an epidemiological review

In this review, we have sought to examine the epidemiological, basic science, and public health data regarding the association between second-hand smoke (SHS) exposure and the development of coronary heart disease (CHD). SHS increases the risk of CHD by 25-30% according to multiple cohort, case-control, and meta-analytical studies. Physiologic and basic science research suggest that the mechanisms by which SHS affects the cardiovascular system are multiple and include increased thrombogenesis and low-density lipoprotein oxidation, decreased exercise tolerance, dysfunctional flow-mediated vasodilatation, and activation of inflammatory pathways with concomitant oxidative damage and impaired vascular repair. As a result, chronic exposure promotes atherogenesis and the development of cardiovascular disease, increasing the risk of having an acute coronary syndrome (ACS). With the implementation of statewide and nationwide public smoke-free legislation across the United States and Europe, respectively, over the last 10-15 years, there has been a significant and reciprocal decline in the incidence of emergency admissions for ACS by an average 17% despite persistent attempts on the part of the tobacco industry to diminish the correlation between SHS exposure and CHD. These findings underscore the importance of the effects of smoking legislation on community health.

Non-cigarette tobacco products: what have we learnt and where are we headed?

A wide variety of non-cigarette forms of tobacco and nicotine exist, and their use varies regionally and globally. Smoked forms of tobacco such as cigars, bidis, kreteks and waterpipes have high popularity and are often perceived erroneously as less hazardous than cigarettes, when in fact their health burden is similar. Smokeless tobacco products vary widely around the world in form and the health hazards they present, with some clearly toxic forms (eg, in South Asia) and some forms with far fewer hazards (eg, in Sweden). Nicotine delivery systems not directly reliant on tobacco are also emerging (eg, electronic nicotine delivery systems). The presence of such products presents challenges and opportunities for public health. Future regulatory actions such as expansion of smoke-free environments, product health warnings and taxation may serve to increase or decrease the use of non-cigarette forms of tobacco. These regulations may also bring about changes in non-cigarette tobacco products themselves that could impact public health by affecting attractiveness and/or toxicity.

Prevalence, distribution and correlates of tobacco smoking and chewing in Nepal: a secondary data analysis of Nepal Demographic and Health Survey-2006

Background

Nearly four-fifths of estimated 1.1 million smokers live in low or middle-income countries. We aimed to provide national estimates for Nepal on tobacco use prevalence, its distribution across demographic, socio-economic and spatial variables and correlates of tobacco use.

Methods

A secondary data analysis of 2006 Nepal Demographic and Health Survey (DHS) was done. A representative sample of 9,036 households was selected by two-stage stratified, probability proportional to size (PPS) technique. We constructed three outcome variables 'tobacco smoke', 'tobacco chewer' and 'any tobacco use' based on four questions about tobacco use that were asked in DHS questionnaires. Socio-economic, demographic and spatial predictor variables were used. We computed overall prevalence for 'tobacco smoking', 'tobacco chewing' and 'any tobacco use' i.e. point estimates of prevalence rates, 95% confidence intervals (CIs) after adjustment for strata and clustering at primary sampling unit (PSU) level. For correlates of tobacco use, we used multivariate analysis to calculate adjusted odds ratios (AORs) and their 95% CIs. A p-value < 0.05 was considered as significant.

Results

Total number of households, eligible women and men interviewed was 8707, 10793 and 4397 respectively. The overall prevalence for 'any tobacco use', 'tobacco smoking' and 'tobacco chewing' were 30.3% (95% CI 28.9, 31.7), 20.7% (95% CI 19.5, 22.0) and 14.6% (95% CI 13.5, 15.7) respectively. Prevalence among men was significantly higher than women for 'any tobacco use' (56.5% versus 19.6%), 'tobacco smoking' (32.8% versus 15.8%) and 'tobacco chewing' (38.0% versus 5.0%). By multivariate analysis, older adults, men, lesser educated and those with lower wealth quintiles were more likely to be using all forms of tobacco. Divorced, separated, and widowed were more likely to smoke (OR 1.49, 95% CI 1.14, 1.94) and chew tobacco (OR 1.36, 95% CI 0.97, 1.93) as compared to those who were currently married. Prevalence of 'tobacco chewing' was higher in eastern region (19.7%) and terai/plains (16.2%). 'Tobacco smoking' and 'any tobacco use' were higher in rural areas, mid-western and far western and mountainous areas.

Conclusions

Prevalence of tobacco use is considerably high among Nepalese people. Demographic and socioeconomic determinants and spatial distribution should be considered while planning tobacco control interventions.

Assessment of smokeless tobacco use in the history and physical examination by primary healthcare providers

PURPOSE

Following a simple descriptive research design, we examined how and to what extent primary healthcare providers in rural southern regions of the United States ask patients about the use of smokeless tobacco as indicated in the document used for the patient history.

DATA SOURCES

Copies of blank history and physical forms used in offices of primary care providers in Alabama, Georgia, South Carolina, and Tennessee were examined to identify items related specifically to tobacco use.

CONCLUSIONS

Twenty-nine providers returned history and physical forms, which revealed 24% showed no item related to tobacco use. Others included questions related to smoking, but only 7% mentioned any sort of smokeless tobacco use.

IMPLICATIONS FOR PRACTICE

Although a few studies have suggested the use of smokeless tobacco to be less harmful than smoking, all forms of smokeless tobacco are recognized carcinogens and dangerous for health. It is not sufficient to simply ask patients about smoking behaviors. Primary care providers, especially nurse practitioners, have the unique opportunity to assess use of smokeless tobacco and to offer treatment and counsel to help patients to stop the behavior.

The association between active smoking, smokeless tobacco, second-hand smoke exposure and insufficient sleep

BACKGROUND

Studies have shown that cigarette smoking is associated with sleep disorders in the general population. But studies examining the association between smokeless tobacco use, second-hand smoke exposure and insufficient rest/sleep are limited.

METHODS

We examined the association between smoking, smokeless tobacco use (n=83,072), second-hand smoke exposure (n=28,557) and insufficient rest/sleep among adults aged ≥20 years in the state-based 2008 Behavioral Risk Factor Surveillance System. Exposure to second-hand smoke was defined as >1 day of exposure to cigarette smoking either at home or in the workplace in the preceding 7 days. Insufficient rest/sleep was defined as not getting enough rest/sleep everyday in the preceding 30 days.

RESULTS

Compared to never smokeless tobacco users, the odds ratio (OR; 95% confidence interval [CI]) of insufficient rest/sleep was 1.16 (1.00-1.36) and 1.74 (1.37-2.22) among former and current users. Compared to non-smokers/non-smokeless tobacco users, the OR (95% CI) of insufficient rest/sleep for those who were both current smokers and current smokeless tobacco users was 2.21 (1.66-2.94). Regarding second-hand smoke exposure among non-smokers, those with second-hand smoke exposure had higher odds for insufficient rest/sleep than those without. In contrast, the odds of insufficient rest/sleep were similar among current smokers with or without second-hand smoke exposure.

CONCLUSIONS

In a multiethnic sample of US adults, compared to non-smokers/non-smokeless tobacco users, those who were both current smokers and current smokeless tobacco users had twice the odds of insufficient sleep. Second-hand smoke exposure was associated with insufficient rest/sleep among non-smokers.

Use of smokeless tobacco and risk of myocardial infarction and stroke: systematic review with meta-analysis

OBJECTIVE

To assess whether people who use smokeless tobacco products are at increased risk of myocardial infarction and stroke.

DESIGN

Meta-analysis of observational studies from Sweden and the United States.

DATA SOURCES

Electronic databases and reference lists.

DATA EXTRACTION

Quantitative estimates of the association between use of smokeless tobacco products and risk of myocardial infarction and stroke among never smokers.

REVIEW METHODS

Both authors independently abstracted risk estimates and study characteristics. Summary relative risks were estimated on the basis of random effects models.

RESULTS

11 studies, mainly in men, were included. Eight risk estimates were available for fatal myocardial infarction: the relative risk for ever use of smokeless tobacco products was 1.13 (95% confidence 1.06 to 1.21) and the excess risk was restricted to current users. The relative risk of fatal stroke, on the basis of five risk estimates, was 1.40 (1.28 to 1.54). The studies from both the United States and Sweden showed an increased risk of death from myocardial infarction and stroke. The inclusion of non-fatal myocardial infarction and non-fatal stroke lowered the summary risk estimates. Data on dose-response were limited but did not suggest a strong relation between risk of dying from either disease and frequency or duration of use of smokeless tobacco products.

CONCLUSION

An association was detected between use of smokeless tobacco products and risk of fatal myocardial infarction and stroke, which does not seem to be explained by chance.

Under-reporting of tobacco use among Bangladeshi women in England

BACKGROUND

This study investigates the prevalence of under-reported use of tobacco among Bangladeshi women and the characteristics of this group.

METHODS

The 1999 and 2004 Health Survey for England included 996 Bangladeshi women aged 16 years and above, 302 with a valid saliva sample and 694 without. The main outcome measure was the prevalence of under-reported tobacco use.

RESULTS

Fifteen per cent of Bangladeshi women with a saliva sample under-reported their personal tobacco use. Under-reporters were very similar to self-reported users except for being much more likely to report chewing paan without tobacco (47% versus 9%, P < 0.001). Under-reporters differed significantly from cotinine-validated non-users in most respects. Regression analyses confirmed that under-reporters and self-reported users were similar in age, education level and exposure to passive smoking. Under-reporters were older and less educated than cotinine-validated non-users. Both self-reported users [odds ratio (OR): 0.11, 95% confidence interval (CI): 0.04-0.30] and cotinine-validated non-users (OR: 0.42, 95% CI: 0.20-0.89) were far less likely to report chewing paan without tobacco compared with under-reporters.

CONCLUSIONS

Contrary to our a priori hypothesis, under-reporters were not young, British-born, English-speaking women likely to be concealing smoking but resembled self-reported tobacco users except for being much more likely to report chewing paan without tobacco.

Smoking cessation pharmacotherapy

Cigarette smoking remains an important risk factor for premature cardiovascular disease and its many complications. There are clear benefits from treating tobacco dependence on the rate of clinical outcomes. In addition to behavioral therapies, various pharmacologic strategies have been developed to help achieve this goal. First-line therapies include nicotine replacement, bupropion and varenicline, a partial nicotine antagonist. Second-line treatments include clonidine and nortriptyline. Additional treatment strategies with less proven efficacy include monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, opioid receptor antagonists, bromocriptine, anti-anxiety drugs, nicotinic receptor antagonists (e.g. mecamylamine) and glucose tablets. Various approaches under investigation include inhibitors of the hepatic P450 enzyme (e.g. methoxsalen), cannabinoid-1 receptor antagonists (e.g. rimonabant), and nicotine vaccines.

A review of the efficacy and effectiveness of harm reduction strategies for alcohol, tobacco and illicit drugs

Harm reduction is both a policy approach and used to describe a specific set of interventions. These interventions aim to reduce the harms associated with drug use. Employing a strict definition of harm reduction, evidence for the efficacy and effectiveness of alcohol, tobacco and illicit drug harm reduction interventions were reviewed. Systematic searches of the published literature were undertaken. Studies were included if they provided evaluation data (pre-post, or control group comparisons). More than 650 articles were included in the review. The majority of the literature concerned illicit drugs. For alcohol, harm reduction interventions to reduce road trauma are well-founded in evidence. Otherwise, there is limited research to support the efficacy and effectiveness of other alcohol harm reduction interventions. For tobacco, the area is controversial but promising new products that reduce the harms associated with smoking are being developed. In the area of illicit drugs there is solid efficacy, effectiveness and economic data to support needle syringe programmes and outreach programmes. There is limited published evidence to date for other harm reduction interventions such as non-injecting routes of administration, brief interventions and emerging positive evidence for supervised injecting facilities. There is sufficient evidence to support the wide-spread adoption of harm reduction interventions and to use harm reduction as an overarching policy approach in relation to illicit drugs. The same cannot be concluded for alcohol or tobacco. Research at a broad policy level is required, especially in light of the failure by many policy makers to adopt cost-effective harm reduction interventions.

Swedish snuff and incidence of cardiovascular disease. A population-based cohort study

Background

The relationship between smoking and an increased incidence of cardiovascular diseases is well known. Whether smokeless tobacco (snuff) is related to myocardial infarction (MI) or stroke is still controversial. Aim of this study was to explore whether snuff users have an increased incidence of MI or stroke.

Methods

A total of 16 754 women and 10 473 men (aged 45–73 years), without history of cardiovascular disease (CVD), belonging to the population-based "Malmö Diet and Cancer" study were examined. Incidence of MI and stroke were monitored over 10.3 years.

Results

Snuff was used by 737 (7.0%) men and 75 (0.4%) women, respectively. Among men, snuff was significantly associated with low occupation level, single civil status, high BMI and with current and former smoking. In women, snuff was associated with lower systolic blood pressure. A total of 964 individuals (3.5%), i.e.544 men (5.3%) and 420 (2.5%) women suffered a MI during the follow-up period. The corresponding numbers of incident stroke cases were 1048, i.e. 553 men (5.3%) and 495 (3.0%) women, respectively. Snuff was not associated with any statistically significant increased risk of MI or stroke in men or women. The relative risks (RR) in male snuff users compared to non-users were 1.05 (95% confidence interval (CI): 0.8–1.4, p = 0.740) for incident MI and 0.97 (0.7–1.4, p = 0.878) for stroke, after taking age and potential confounders into account. In women none of the 420 (2.5%) women who were snuff users had a MI and only one suffered a stroke during the follow-up.

Conclusion

Several life-style risk factors were more prevalent in snuff-users than in non-users. However, the present study does not support any relationship between snuff and incidence of cardiovascular disease in men.

Should doctors advocate snus and other nicotine replacements? Yes

Use of snus is less harmful than smoking and John Britton thinks that doctors should suggest it to people who are unable to give up cigarettes. But Alexander Macara argues that it could result in increased use of tobacco

Changing smokeless tobacco products new tobacco-delivery systems

Smokeless or noncombusted oral tobacco use as a substitute for cigarette smoking has been gaining greater interest and attention by the public health community and the tobacco industry. In order for the product to appeal to smokers, tobacco companies have been manufacturing new noncombusted oral tobacco (i.e., moist snuff) that is lower in moisture content and nitrosamine levels, packaged in small sachets and "spitless." While the primary motives of the major tobacco companies are to maintain or increase tobacco use, some members of the public health community perceive the use of noncombusted oral tobacco products as a harm reduction tool. Because cigarette smoking is associated with greater toxicant exposure compared to noncombusted oral tobacco, reduced mortality and morbidity are hypothesized to ensue, if cigarette smokers switched completely to these products. However, variability exists in levels of nicotine and toxicants and potential health consequences from use within and across countries. Therefore, promulgating noncombusted oral tobacco products as a safer alternative to smoking or as a substitute for smoking may engender more rather than less harm. To date, limited research is available on the effects of marketing noncombusted oral tobacco products to smokers, to support the use of these products as a harm reduction tool, and to determine the effects of varying levels of tobacco toxicants including nicotine on health. The need exists for manufacturing standards to lower toxicant levels of all noncombusted oral tobacco products, for the formulation of appropriate tobacco-product regulations and for the development of a strategic plan by the public health community to address this controversial topic.

Epidemiologic perspectives on smokeless tobacco marketing and population harm

Moist snuff is the most popular form of orally-used smokeless tobacco in North America and parts of Europe. Because moist snuff use conveys lower risks for morbidity or mortality than does cigarette smoking, its use has been proposed as a tobacco harm-reduction strategy. This article critically reviews new and published epidemiologic evidence on health effects of moist snuff and its patterns of use relative to smoking in the United States, Sweden, and Norway. The available evidence suggests that: (1) moist snuff is a human carcinogen and toxin, (2) increased promotion of moist snuff has led to increased sales in those countries, (3) the uptake of moist snuff in these three countries during the past several decades has occurred primarily among adolescent and young adult men, (4) increased prevalence of snuff use has not been associated consistently with a reduction in smoking initiation or prevalence, (5) moist snuff use apparently plays a very minor role in smoking cessation in the U.S. and an inconsistent role in Sweden, (6) U.S. states with the lowest smoking prevalence also tend to have the lowest prevalence of snuff use, (7) there are no data on the efficacy of snuff as a smoking-cessation method, (8) the prevalence of cigarette smoking is relatively high among people who use snuff, and (9) snuff use is more consistently associated with partial substitution for smoking than with complete substitution. The evidence base for promotion of snuff use as a public health strategy is weak and inconsistent.

Circulatory disease and smokeless tobacco in Western populations: a review of the evidence

BACKGROUND

Use of oral snuff or 'snus' has risen in Sweden. Sales of snuff in the US have also risen, overtaking sales of chewing tobacco. There is some evidence that nicotine contributes to circulatory disease (CID) from smoking. We therefore reviewed the evidence relating smokeless tobacco (ST) to CID and related risk factors.

METHODS

Publications that described relevant cohort, case-control and cross-sectional studies were identified from in-house files, a Medline search in December 2005 and reference lists. Relative risks (RRs) and odds ratios (ORs) for ischaemic heart disease, stroke and all CID for ST use, stratified by smoking habit, were estimated and combined by meta-analysis to provide an overall RR estimate. For diabetes, increased blood pressure, and other risk factors, evidence was qualitatively reviewed, with results from clinical studies also considered.

RESULTS

ST use in non-smokers was associated with an increased risk of heart disease (RR 1.12, 95% CI 0.99-1.27, n = 8), stroke (1.42, 1.29-1.57, n = 5) and CID (1.25, 1.14-1.37, n = 3). The increases mainly derived from two large US studies. The Swedish studies provided little evidence of an increase for heart disease (1.06, 0.83-1.37, n = 5) or stroke (1.17, 0.80-1.70, n = 2), although the estimates by country are not notably heterogeneous, even for stroke (P = 0.29). No dose-response was evident. No increase was seen in former users of ST, or in ST users who also smoked. No clear relationship to diabetes was seen. In the US, an acute blood pressure rise following ST use was consistently reported, and isolated reports linked specific risk factors to ST. In Sweden, though one study reported that snuff acutely increased blood pressure, and two linked snuff to Raynaud-type symptoms, the overall evidence for an effect was inconclusive. Swedish studies generally showed no chronic effect of snuff on blood pressure or various risk factors.

CONCLUSIONS

Any CID risk from ST appears to be substantially less than from smoking, and no clear risk from Swedish snuff is seen. However, the overall evidence is limited.

Smoking Cessation Pharmacotherapy?Nicotine and Non-Nicotine Preparations

Cigarette smokers tend to die prematurely from a number of diseases. Cigarette smoking is an important modifiable risk factor for cardiovascular morbidity and mortality. Despite the clear health benefits of smoking cessation, smokers usually find it difficult to stop and behavioral therapies often prove insufficient. Pharmacologic intervention may aid the process because of the addictive nature of nicotine. Nicotine replacement therapy, which is regarded as first-line therapy, was developed to overcome the symptoms of nicotine withdrawal that many patients find distressing. Different modes of administration include inhalation and buccal or transdermal absorption. The orally administered non-nicotine drugs varenicline and bupropion are also regarded as first-line treatments, either used alone or as an adjunct to nicotine replacement therapy. Second-line treatments include clonidine and nortriptyline. Other treatment strategies that have been examined include monoamine oxidase inhibitors and selective serotonin reuptake inhibitors; efficacy has yet to be proven definitively. A novel approach to treatment using the cannabinoid-1 receptor antagonist rimonabant is also under investigation.

Tobacco-related disease mortality among men who switched from cigarettes to spit tobacco

BACKGROUND

Although several epidemiological studies have examined the mortality among users of spit tobacco, none have compared mortality of former cigarette smokers who substitute spit tobacco for cigarette smoking ("switchers") and smokers who quit using tobacco entirely.

METHODS

A cohort of 116,395 men were identified as switchers (n = 4443) or cigarette smokers who quit using tobacco entirely (n = 111,952) when enrolled in the ongoing US American Cancer Society Cancer Prevention Study II. From 1982 to 31 December 2002, 44 374 of these men died. The mortality hazard ratios (HR) of tobacco-related diseases, including lung cancer, coronary heart disease, stroke and chronic obstructive pulmonary disease, were estimated using Cox proportional hazards regression modelling adjusted for age and other demographic variables, as well as variables associated with smoking history, including number of years smoked, number of cigarettes smoked and age at quitting.

RESULTS

After 20 years of follow-up, switchers had a higher rate of death from any cause (HR 1.08, 95% confidence interval (CI) 1.01 to 1.15), lung cancer (HR 1.46, 95% CI 1.24 to 1.73), coronary heart disease (HR 1.13, 95% CI 1.00 to 1.29) and stroke (HR 1.24, 95% CI 1.01 to 1.53) than those who quit using tobacco entirely.

CONCLUSION

The risks of dying from major tobacco-related diseases were higher among former cigarette smokers who switched to spit tobacco after they stopped smoking than among those who quit using tobacco entirely.

Nicotine and non-nicotine smoking cessation pharmacotherapies

Cigarette smoking remains an important risk factor for premature cardiovascular disease and its complications. There are clear benefits of cigarette smoking cessation on the rate of clinical outcomes, and in addition to behavioral therapies, various pharmacologic strategies have been developed to help achieve this goal. First-line therapies include nicotine replacement and/or bupropion. Second-line treatments include clonidine and nortriptyline. Additional treatment strategies, with less proven efficacy, include monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, opioid receptor antagonists, bromocriptine, antianxiety drugs, nicotinic receptor antagonists (eg, mecamylamine), and glucose tablets. Various approaches under investigation include the use of partial nicotine agonists (eg, varenicline), inhibitors of the hepatic P-450 enzyme (eg, methoxsalen), cannaboid-1 receptor antagonists (eg, rimonabant), and nicotine vaccines.

The smoking gun: many conditions associated with tobacco exposure may be attributable to paradoxical compensatory autonomic responses to nicotine

Tobacco exposure is implicated in many illnesses such as cardiovascular disease and cancer, but the mechanisms underlying these associations are poorly understood. The mechanisms by which tobacco induces pro-sympathetic and pro-inflammatory changes also remain elusive. Some studies have attributed these changes to the direct effects of nicotine, but such findings run counter to the pro-vagal, anti-inflammatory nature of the nicotinic pathway. We hypothesize that the illnesses associated with smoking may be partly attributable to autonomic dysfunction, sympathetic bias, and T helper (Th)2 inflammation induced by a paradoxical compensatory response to intermittent nicotinic exposure. The confusion of interpreting the adrenergia and inflammation associated with nicotine as a primary response instead of a secondary compensation may be explained by the unusually rapid absorption, action, and serum elimination of nicotine. Given the fast action and clearance of nicotine, even heavy smokers spend large portions of the day and the entire night in nicotine withdrawal, at which time rebound sympathetic bias may manifest as a result of desensitization of nicotinic receptors. This may help reconcile why the features observed in smokers such as tachycardia, hypertension, inflammation, insomnia, and anxiety, which are perhaps mistakenly attributed to the direct action of nicotine, are identical to those seen during acute nicotine withdrawal after smoking cessation. On the other hand, delayed responses to cessation of smoking such as weight gain and increased heart rate variability are compatible with reduced sympathovagal ratio and resensitization of nicotinic receptors. Sympathetic bias and the associated Th2 inflammation underlie many systemic diseases. Tobacco-related cancers may be partly attributable to immunomodulatory properties of chronic nicotine exposure by dampening Th1 immunity and enabling tumoral evasion of immune surveillance. Other conditions associated with tobacco exposure may also operate through similar autonomic and immune dysfunctions. Therapeutic implications are discussed.

Plasma Fibrinogen Level: an Independent Risk Factor for Long-term Survival in Chinese Patients with Peripheral Artery Disease?

Fibrinogen, an inflammatory marker as well as a fundamental part of the coagulation cascade, is suggested to play a significant role in the pathogenesis of atherosclerosis and complications of atherothrombotic diseases. The aim of this study was to determine if plasma fibrinogen is an independent risk factor for long-term survival in patients with peripheral artery disease (PAD). Altogether, 139 Chinese patients (88 men, 51 women) with PAD were consecutively recruited for the study. Atherothrombotic risk factors and fibrinogen levels were determined at presentation, and all patients were followed up for mortality prospectively. The mean follow-up was 6 years. All variables were first correlated with survival rates using Kaplan-Meier analysis and compared by means of the log-rank test. Significant risk factors were identified, and multivariate Cox regression analysis was used to evaluate the independent contribution of the fibrinogen level to the risk of mortality. During follow-up, 95 patients (68.3%) died. The overall survival rate was 77.7% at 3 years, 56.8% at 5 years, and 31.2% at 10 years (standard errors 0.05, 0.06, and 0.07, respectively). All-cause mortality rate increased with an elevated fibrinogen level. Eighty percent of patients with a fibrinogen level > 3.4 g/L had a survival time of less than 3 years (p = 0.002). This relation was also demonstrated within patients with critical ischemia. The plasma fibrinogen level was thus identified as an independent risk factor for mortality in PAD patients after adjusting for confounding factors.