Search

The prevalence of vaping, also known as using e-cigarettes, vapes, vape pens, or electronic nicotine delivery systems (ENDS) has prompted a demand for reliable, evidence-based research.1However, published literature on the topic of vaping is often unreliable, characterized by serious flaws and a failure to adhere to accepted scientific methodologies. In this narrative review, we analyze 24 popular vaping studies, published in medical journals, that purport to evaluate the association of vaping and smoking initiation, smoking cessation or health outcomes. We analyzed these studies to identify the questions they claimed to address, stated methods, manner of implementation, discussions, and stated conclusions. After critical appraisal, we noted a multiplicity of flaws in these studies, and identified patterns as to the nature of such flaws. Many studies lacked a clear hypothesis statement: to the extent that a hypothesis could be inferred, the methods were not tailored to address the question of interest. Moreover, main outcome measures were poorly identified, and data analysis was further complicated by failure to control for confounding factors. The body of literature on “gateway” theory the for initiation of smoking was particularly unreliable. Overall, the results and discussion contained numerous unreliable assertions due to poor methods, including data collection that lacked relevance, and assertions that were unfounded. Many researchers claimed to find a causal association while not supporting such findings with meaningful data: the discussions and conclusions of such studies were therefore misleading. Herein, we identify the common flaws in the study design, methodology, and implementation found in published vaping studies. Our aim is to prompt future researchers to adhere to scientific methods to produce more reliable findings and conclusions in the field of vaping research

Introduction The objective was to systematically review studies on health outcomes from smokeless tobacco (SLT) products. Methods We analysed published literature on the health outcomes from SLT use between 01/01/2015 to 01/02/2020, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol using PubMed, Embase, Scopus, and Google Scholar. Results Of 53 studies included, six were global, 32 from Asia, Middle East and Africa (AMEA), nine from USA and six from Europe. ‘Poor’-rated studies predominated (23;43%), in particular, for global (4;66%) and AMEA (16;50%). Health outcomes differed between SLT-products and regions; those in AMEA were associated with higher mortality (overall, cancer, Coronary heart disease (CHD), respiratory but not cardiovascular disease (CVD)), and morbidity (CVD, oral and head and neck cancers), with odds ratios up to 38.7. European studies showed no excess mortality (overall, CVD, from cancers) or morbidity (ischemic heart disease (IHD), stroke, oral, head and neck, pancreatic or colon cancers) from several meta-analyses; single studies reported elevated risk of rectal cancer and respiratory disorders. Pooled study data showed protection against developing Parkinson’s disease. US studies showed mixed results for mortality (raised overall, CHD, cancer and smoking-related cancer mortality; no excess risk of respiratory or CVD mortality). Morbidity outcomes were also mixed, with some evidence of increased IHD, stroke and cancer risk (oral, head and neck). No studies reported on switching from cigarettes to SLT-products. Conclusion Our review demonstrates stark differences between different SLT-products in different regions, ranging from zero harm from European snus to greatly increased health risks in AMEA. The literature on the safety profile for SLT-products for harm reduction is incomplete and potentially misinforming policy and regulation.

The objective of this systematic review was to identify, report and critically appraise studies that have reported health outcomes from use of electronic nicotine delivery systems (ENDS). We conducted a systematic review of all published literature on the health impact of ENDS products from 1st January 2015 until February 1, 2020, following the PRISMA protocol, including across the databases, PubMed, Embase, Scopus and Google Scholar using medical subject headings. A category for the level of evidence was assigned blindly using the Centres for Evidence Based Medicine framework. A similar approach was adopted to evaluate methodological quality of each study utilizing the National Institutes for Health (NIH) Quality Assessment Tools. The database search identified 755 studies and a further 265 were identified from other sources and reference reviews of which 37 studies met the eligibility criteria. The majority of studies were of low strength for levels of evidence including 24 (65%) cross-sectional, 1(2.7%) case-control and six (16%) case studies. There were four (11%) cohort studies and only one (2.7%) RCT. There was only one (2.7%) meta-analysis or pooled study of observational study designs; there were no pooled results of randomized controlled trials. Of 37 studies, eight (22%) studies reported on benefits, two (2%) studies were neutral, reporting on both harm and benefits, the remaining 27 (73%) reported only on harms. The quality ratings were poor (20, 54%), fair (9, 24%) and good (8, 22%). In our review ENDS use has not been shown to be causative for any CVD outcomes and has been shown to be beneficial for hypertensive patients. Switching from cigarettes to e-cigarettes resulted in reduced exacerbations of COPD, with no evidence of long-term deterioration in lung function. There was a suggestion of short-term reductions in respiratory function in asthmatics, but no increased risk of asthma in ENDS users who were never smokers. Mental Health, cancer and mortality have not been adequately studied to form any consensus with regards to health outcomes from ENDS use. Our review suggests that the majority of studies on the use of ENDS products reported on negative health impacts with few reporting on health outcomes from switching from cigarettes to e-cigarettes. The strength of evidence and quality of the published studies overall is poor. Our review has demonstrated that ENDS use is not causative for any harmful CVD outcomes and may be beneficial for hypertensive patients. Switching from cigarettes to e-cigarettes resulted in reduced exacerbations of COPD, with no evidence of increased risk of asthma, long-term respiratory harm or deterioration in lung function. Other health outcomes such as mental health, cancer and mortality have not been adequately studied to form a consensus. However, the findings of our review did not negate the consensus held by many that ENDS use is safer than the risks posed from smoking cigarettes. Overall, our review found the research on ENDS use is not yet adequate to provide quantitative estimates about health risks. Consequently, the current body of evidence is inadequate for informing policy around tobacco harm reduction.