Dataset Information

Current and former smoking and risk for venous thromboembolism: a systematic review and meta-analysis.

ABSTRACT:

Background

Smoking is a well-established risk factor for atherosclerotic disease, but its role as an independent risk factor for venous thromboembolism (VTE) remains controversial. We conducted a meta-analysis to summarize all published prospective studies and case-control studies to update the risk for VTE in smokers and determine whether a dose-response relationship exists.

Methods and findings

We performed a literature search using MEDLINE (source PubMed, January 1, 1966 to June 15, 2013) and EMBASE (January 1, 1980 to June 15, 2013) with no restrictions. Pooled effect estimates were obtained by using random-effects meta-analysis. Thirty-two observational studies involving 3,966,184 participants and 35,151 VTE events were identified. Compared with never smokers, the overall combined relative risks (RRs) for developing VTE were 1.17 (95% CI 1.09-1.25) for ever smokers, 1.23 (95% CI 1.14-1.33) for current smokers, and 1.10 (95% CI 1.03-1.17) for former smokers, respectively. The risk increased by 10.2% (95% CI 8.6%-11.8%) for every additional ten cigarettes per day smoked or by 6.1% (95% CI 3.8%-8.5%) for every additional ten pack-years. Analysis of 13 studies adjusted for body mass index (BMI) yielded a relatively higher RR (1.30; 95% CI 1.24-1.37) for current smokers. The population attributable fractions of VTE were 8.7% (95% CI 4.8%-12.3%) for ever smoking, 5.8% (95% CI 3.6%-8.2%) for current smoking, and 2.7% (95% CI 0.8%-4.5%) for former smoking. Smoking was associated with an absolute risk increase of 24.3 (95% CI 15.4-26.7) cases per 100,000 person-years.

Conclusions

Cigarette smoking is associated with a slightly increased risk for VTE. BMI appears to be a confounding factor in the risk estimates. The relationship between VTE and smoking has clinical relevance with respect to individual screening, risk factor modification, and the primary and secondary prevention of VTE. Please see later in the article for the Editors' Summary.

SUBMITTER: Cheng YJ

PROVIDER: S-EPMC3775725 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Publications

Current and former smoking and risk for venous thromboembolism: a systematic review and meta-analysis.

Cheng Yun-Jiu YJ Liu Zhi-Hao ZH Yao Feng-Juan FJ Zeng Wu-Tao WT Zheng Dong-Dan DD Dong Yu-Gang YG Wu Su-Hua SH

PLoS medicine 20130917 9

<h4>Background</h4>Smoking is a well-established risk factor for atherosclerotic disease, but its role as an independent risk factor for venous thromboembolism (VTE) remains controversial. We conducted a meta-analysis to summarize all published prospective studies and case-control studies to update the risk for VTE in smokers and determine whether a dose-response relationship exists.<h4>Methods and findings</h4>We performed a literature search using MEDLINE (source PubMed, January 1, 1966 to Jun ...[more]

PMID: 24068896

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Project description:Background:The purpose of this study was to examine the prevalence and effects of current smoking on adverse outcomes among hospitalized COVID-19 patients.Methods:A systematic review of the literature (PubMed) identified 18 (from a total of 1398) relevant studies. Pooled current smoking prevalence was compared with the gender-adjusted and gender and age-adjusted, population-based expected prevalence by calculating prevalence odds ratio (POR). The association between current, compared with non-current and former, smoking and adverse outcome was examined. A secondary analysis was performed by including 12 pre-publications (30 studies in total). All analyses were performed using random-effects meta-analysis.Results:Among 6515 patients, the pooled prevalence of current smoking was 6.8% [95% confidence interval (CI): 4.8–9.1%]. The gender-adjusted POR was 0.20 (95% CI: 0.16–0.25, p?<?0.001), and the gender and age-adjusted POR was 0.24 (95% CI: 0.19–0.30, p?<?0.001). Current smokers were more likely to have an adverse outcome compared with non-current smokers [odds ratio (OR): 1.53, 95%CI: 1.06–2.20, p?=?0.022] but less likely compared with former smokers (OR: 0.42, 95% CI: 0.27–0.74, p?=?0.003). When pre-publications were added (n?=?10,631), the gender-adjusted POR was 0.27 (95% CI: 0.19–0.38, p?<?0.001) and the gender and age-adjusted POR was 0.34 (95% CI: 0.24–0.48, p?<?0.001).Conclusion:This meta-analysis of retrospective observational case series found an unexpectedly low prevalence of current smoking among hospitalized patients with COVID-19. Hospitalized current smokers had higher odds compared with non-current smokers but lower odds compared with former smokers for an adverse outcome. Smoking cannot be considered a protective measure for COVID-19. However, the hypothesis that nicotine may have a protective effect in COVID-19 that is partially masked by smoking-related toxicity and by the abrupt cessation of nicotine intake when smokers are hospitalized should be explored in laboratory studies and clinical trials using pharmaceutical nicotine products.

Project description:Background: Patients suffering from chronic inflammatory disorders, such as inflammatory bowel disorder, are at higher risk of developing thromboembolism. The chronic inflammatory nature of inflammatory bowel disease has been identified as a predominant reason for a state of Virchow's triad (i.e., endothelial dysfunction, stasis, and general hypercoagulability), eventually leading to the onset of venous thromboembolism. Recent studies show that certain factors, such as demographics, medication history, and history of surgical intervention may increase thromboembolism risk in patients with inflammatory bowel disease. However, to date, no study has attempted to evaluate the effect of different risk factors associated with the development of venous thromboembolism in inflammatory bowel disease patients. Objective: To evaluate the risk factors that can influence the incidence of venous thromboembolism in patients with inflammatory bowel disease. Methods: Academic literature was systematically searched based on the PRISMA guidelines across five databases: Web of Science, EMBASE, CENTRAL, Scopus, and MEDLINE. A random-effect meta-analysis was conducted to evaluate the hazard ratio for the risk factors (i.e., aging, gender, steroid therapy, surgery, and ulcerative colitis) that can influence the incidence of venous thromboembolism in patients with inflammatory bowel disease. Results: From a total of 963 studies, 18 eligible studies with 1,062,985 (44.59 ± 10.18 years) patients suffering from inflammatory bowel disease were included in the review. A meta-analysis revealed a higher risk of aging (Hazard's ratio: 2.19), steroids (1.87), surgery (1.48), and ulcerative colitis (2.06) on venous thromboembolism in patients with inflammatory bowel disease. We also found that the female gender (0.92) did not increase the incidence of venous thromboembolism in inflammatory bowel disease patients. Conclusion: The study provides preliminary evidence regarding high risks associated with ulcerative colitis, steroid consumption, and aging for the development of venous thromboembolism in patients with inflammatory bowel disease. The findings from this study may contribute to developing awareness among clinicians, better risk stratification and prevention of venous thromboembolic complications in patients with inflammatory bowel disease.

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Dataset Information

Current and former smoking and risk for venous thromboembolism: a systematic review and meta-analysis.

Background

Methods and findings

Conclusions

Publications

Current and former smoking and risk for venous thromboembolism: a systematic review and meta-analysis.

Similar Datasets

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