eLetters

1326 e-Letters

  • Incorrect classification of vaping regulations

    The potential impact of e-cigarette use on smoking prevalence is an important public health question. The Wu et al. paper examines this question by comparing changes in smoking prevalence across three jurisdictions with different e-cigarette regulations: Canada, the UK, and Australia.

    The paper concludes that cigarette consumption and smoking prevalence decreased to a greater extent in jurisdictions with less restrictive e-cigarette regulations. This would be a noteworthy finding; however, the paper suffers from a fundamental flaw in terms of how jurisdictions have been categorized. Canada is coded as the ‘least restrictive’ regulatory environment, the UK as ‘more restrictive’, and Australia as ‘most restrictive’, on the basis that no nicotine-containing e-cigarettes were legal for sale in Australia. The authors appear to be unaware that, prior to a legislative change in 2018, nicotine-containing e-cigarettes were not legal for sale in Canada.1,2 Thus, during the period examined in the study (2012 to 2018), Canada had the most restrictive vaping regulations possible, which were materially no different than Australia. In contrast, the UK is widely regarded as having one of the least restrictive markets for e-cigarettes in the world: while nicotine-containing e-cigarettes were prohibited in Canada and Australia, in the UK e-cigarettes were legally sold and marketed in a wide variety of retail locations, and government agencies officially endorsed the harm reduction p...

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  • Self-harm and suicidality in patients with eating disorders with special reference to comorbid psychiatric disorder

    Cliffe et al. conducted a retrospective cohort study to determine the risk of self-harm and suicidality in patients with eating disorders (1). The odds ratios (ORs) (95% confidence intervals) of patients reporting either self-harm or suicidality for a diagnosis of anorexia nervosa (AN) were 3.44 (1.05 to 11.3) and 8.20 (2.17 to 30.1), respectively. The authors also reported that patients reporting either self-harm or suicidality have a risk of have a diagnosis of borderline personality disorder, bipolar disorder or substance misuse disorder, and I have a query about their study.

    The authors also conducted a multivariable logistic regression analysis, and I recommend adopting adjusted ORs as a preferable evidence. AN and bulimia nervosa may present different risk of self-harm and suicidality in patients with eating disorders, and causal association may be difficult to be confirmed by an epidemiological study. According to multivariable analysis, the adjusted ORs of depression, bipolar disorder, personality disorder excepting borderline diagnosis, alcohol use disorder and substance misuse were significantly associated with self-harm or suicidality in patients with eating disorder. Anyway, time trend analysis by using incidence data of eating disorder, comorbid diagnosis, self-harm and suicidality should be conducted for determining causal association.

    References
    1. Cliffe C, Seyedsalehi A, Vardavoulia K, et al. Using natural language processing to extract...

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  • A bewildering study with a head-scratching analysis

    This paper attempts to assess the impact of vaping regulations on tobacco use, using the natural experiment of differing regulatory approaches in Canadian provinces and in other countries. The regulatory distinctions explored are maximum nicotine concentration (characterized as maximum permissible nicotine), minimum age for purchase and sales, and restrictions on marketing, and advertisement.

    What makes the study design bewildering is the choice of a time period for analysis (2012-2018) that predates the legal sale of e-cigarettes in Canada. Nicotine vaping products were not legal for sale in Canada until the Tobacco and Vaping Products Act (TVPA) came into force in May 2018. Prior to this time, inhalable nicotine was regulated under the Food and Drugs Act, which required manufacturers to demonstrate safety, quality and efficacy before being authorized to sell their products. (1) Because no manufacturers had done so, e-cigarettes were illegal for sale in Canada for 6 of the 7 years of this study.

    The paper states that during the study period the maximum nicotine in Canada was 66 mg/ml. There was no maximum level on nicotine concentration until July 2020, when the level was set at 66 mg/ml (2), before being reduced to 20 mg/ml a year later (3). That is, for almost all of the period of the study (until May 2018), the maximum nicotine concentration was 0 mg/ml, and during the last 7 months of the study period (May to December 2018) there was no maximum limit...

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  • Letter To The Editor; Dosage and Inclusion Criteria

    I found this study to be informative and well put together. The quality is highly marked thanks to the tools this study has used such as GRADE. I also believe it useful to include both observational studies and interventional studies. However, I am concerned with the inclusion criteria of this systematic review. Although many studies that are included fit strict criteria, I find it difficult to understand why other studies are included at all. For example, studies administering a dosage of 1g/daily or less of EPA and/or DHA are included to measure effectiveness. However, it is evident that such a small dose (less than 1g/day) is often ineffective.1,2 A dosage less than 2g/daily has been shown to be either too small to measure, has limited benefit, or has no effect.3,4,5 This can skew the data in a direction that makes EPA and/or DHA appear to not be as effective as their true therapeutic value. Even in cases where a benefit is seen at a low dose, how much and what other effects are missed because of this dosage? This is a common error seen among review articles in regards to EPA and/or DHA. In this particular case, the dose may indeed determine the effect.
    References
    1. Kris-Etherton PM, Harris WS, Appel LJ; American Heart Association. Nutrition Committee. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease [published correction appears in Circulation. 2003 Jan 28;107(3):512.]. Circulation. 2002;106(21):2747-2757. doi:10.1161/01.cir.0000...

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  • Infection biomarkers in asthma: Important not to miss using the best ones

    The Intracell Research Group (IRG, www.intracellresearchgroup.com) is a global research consortium consisting of microbiologists, neuroscientists, asthma clinical researchers, physicians, life sciences professionals and others advocating for the study of chronic intracellular infections as potential causes for chronic inflammatory diseases of unknown etiology with emphasis on Alzheimer’s, Asthma, Coronary Heart Disease, and Crohn’s. We wish to comment on the exciting protocol of Kyvsgaard et al.1 published recently in BMJ Open, of a 3-day treatment with azithromycin or long-term vitamin D (to affect short- and long-term symptomatology, respectively) in preschool patients hospitalized with acute asthma-like episodes. Previous work by Stokholm et al.2 in children with asthma-like symptoms found that a 3-day treatment with azithromycin was effective in the short-term but did not significantly affect the time to next episode of troublesome lung symptoms in individual children. We applaud inclusion of microbiologic measurements in the protocol and wish to point out how the investigation of associations of infection and treatment response may be augmented.

    The Kyvsgaard protocol microbiologic methods may fail to detect important atypical respiratory pathogens that are prone to produce chronic infections and that have been associated with asthma. In chronic infections, Chlamydia pneumoniae and Mycoplasma pneumoniae may re...

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  • Possible ways to improve the MSARIMA forecasts

    It is highly likely that the use of the Office for National Statistics output area classification (OAC) may improve the MSARIMA forecasts. This is based on the observation that different social groups exhibit different health care behaviours [1-4]. Hopefully this approach will be of benefit.

    1. Beeknoo N, Jones R. Factors influencing A&E attendance, admissions and waiting times at two London hospitals. Journal of Advances in Medicine and Medical Research 2016;17(10): 1-29.

    2. Beeknoo N, Jones R. Using Social Groups to Locate Areas with High Emergency Department Attendance, Subsequent Inpatient Admission and Need for Critical Care. Journal of Advances in Medicine and Medical Research 2016; 18(6): 1-23. http://www.sciencedomain.org/abstract/16693

    3. Beeknoo N, Jones R Using Social Groups to Locate Areas with High Emergency Department Attendance, Subsequent Inpatient Admission and Need for Critical Care. Journal of Advances in Medicine and Medical Research2016; 18(6): 1-23.

    4. Beeknoo N, Jones R (2016) Using social groups to locate areas of high utilization of critical care. Brit J Healthc Manage 2016; 22(11): 551-560.

  • Editors' Note

    BMJ Open thanks the author of the posted response for their comments.

    We have published a Correction notice with an updated Competing Interests statement provided by the authors. This Correction can be viewed here: https://bmjopen.bmj.com/content/12/3/e051410corr1

  • Dubious Noise Mining Used to Denigrate Genuine Medical Research

    I write because this study was cited by a rather offensive opinion piece published on the morning of April 21, 2022 in the Washington Post. While that opinion made no particular argument beyond a rather vague claim that research into hormonal contraceptives for men is without merit on the grounds that men have no interest in contraception, it did cite this study in support of the claim that "men are 'less likely' to wear a condom when they judge a partner to be attractive or in good health." While the relationship between this claim and the rest of the column is tenuous, it seems to me like a fair characterization of the study authors' conclusion.

    However, on reading the study, I have difficulty trusting even that claim. My concern is that this study looks like little more than noise-mining: questionable data with superficial resemblance to the purported research question, hammered with a grab-bag of statistical techniques for significant-seeming results with an arguable relationship to the researchers' conclusion. I should admit here at the outset that I do not have the statistical background to give an in-depth critique of the mathematical analysis of the results. Still, there are certain numerical hallmarks that lead me to question the confidence that any conclusion about men in general can be drawn from these data.

    - First, the sample size in this study is absurdly small. As a rough metric, we can observe some quirks in the d...

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  • Methodological concerns regarding "Identifying features of quality in rural placements for health students: scoping review"

    A potential methodological limitation with regard to the use of Campbell et al.'s work-integrated learning (WIL) framework is a remaining concern for this otherwise competent and revealing review.

    Authors describe this framework as follows: "Campbell et al’s framework to support assurance of institution-wide quality in WIL is an evidence-based and comprehensive instrument that groups elements required for high quality WIL into four domains: student experience, curriculum design, institutional requirements and stakeholder engagement." (p.3). The two sources cited for this description are the framework itself and Campbell et al. IJWIL 2021;22:505–19. Examining the first source reveals this framework evolved from a partnership between three universities in Australia, and it is not clear to what extent the WIL framework been adopted outside of this network domestically nor internationally. Clarifying this is necessary given the international scope of this evidence overview, and authors state this in the Discussion.

    However, the claim the framework is an "evidence-based and comprehensive instrument" is problematic if it is based on the cited literature. The second citation quotes interviews with Australian higher-education faculty and administrators in a workshop setting, but this kind of self-assessment is not empirical evidence of the "quality" of learner experience. Campbell et al. appear cognizant of this when writing,...

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  • Acceptance of COVID-19 vaccines in sub-Saharan Africa over time

    The question of COVID-19 vaccine acceptance in Sub-Saharan Africa remains of considerable interest as vaccination campaigns are finally underway but vaccination rates are still lagging in most countries in the region.
    Since publishing this paper, we have reported the results from new survey rounds in our High Frequency Phone Surveys (HFPS) series in a blog post. The focus of this new set of results is on vaccine acceptance rates over time. Our surveys in Burkina Faso, Ethiopia, Malawi, Nigeria, and Uganda allowed us to observe the vaccine acceptance of the same respondents once in 2020 and then a second time in 2021. We asked: How stable have the high levels of COVID-19 vaccine acceptance in Sub-Saharan Africa remained between 2020 and 2021?
    We found that overall vaccine acceptance remained high – but with some caveats. In Burkina Faso, Ethiopia, and Nigeria acceptance rates started high at above 75 percent, and then fell by between 1.5 and 6 percentage points over time (Burkina Faso, 2020: 75.7%, 2021: 69.4%; Ethiopia, 2020: 98%, 2021: 96.6%; Nigeria: 2020, 87.5%, 2021: 83.2%). However, these differences are not statistically significant. In contrast, in Malawi, we observed a larger relative drop in acceptance of nine percentage points which was statistically significant (Malawi, 2020: 82.6%, 2021: 73.4%). Finally, in Uganda we observed a statistically significant increase in vaccine acceptance from 84.2% in 2020 to 88.8% in 2021.
    Beyond the aggregate fi...

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