Identifying e-cigarette content on TikTok: Using a BERTopic Modeling approach.

INTRODUCTION: The use of hashtags is a common way to promote e-cigarette content on social media. Analysis of hashtags may provide insight into e-cigarette promotion on social media. However, the examination of text data is complicated by the voluminous amount of social media data. This study used machine learning approaches (i.e., Bidirectional Encoder Representations from Transformers [BERT] topic modeling) to identify e-cigarette content on TikTok. METHODS: We used 13 unique hashtags related to e-cigarettes (e.g., #vape) for data collection. The final analytic sample included 12,573 TikTok posts. To identify the best fitting number of topic clusters, we used both quantitative (i.e., coherence test) and qualitative approaches (i.e., researchers checked the relevance of text from each topic). We, then, grouped and characterized clustered text to each theme. RESULTS: We evaluated that N=18 was the ideal number of topic clusters. The 9 overarching themes were identified: Social media and TikTok-related features (N=4; "duet", "viral"), Vape shops and brands (N=3; "store"), Vape tricks (N=3; "ripsaw"), Modified use of e-cigarettes (N=1; "coil", "wire"), Vaping and girls (N=1; "girl"), Vape flavors (N=1; "flavors"), Vape and cigarettes (N=1; "smoke"), Vape identities and communities (N=1; "community"), and Non-English language (N=3; Romanian and Spanish). CONCLUSIONS: This study used a machine learning method, BERTopic modeling, to successfully identify relevant themes on TikTok. This method can inform future social media research examining other tobacco products, and tobacco regulatory policies such as monitoring of e-cigarette marketing on social media. IMPLICATIONS: This study can inform future social media research examining other tobacco products, and tobacco regulatory policies such as monitoring of e-cigarette marketing on social media.

Use of ENDS devices and modifications to vape cannabis among adolescents and young adults who also vape nicotine.

BACKGROUND: Electronic nicotine delivery systems (ENDS) are the most used tobacco product among adolescents and young adults (AYAs) and are increasingly used to vape cannabis. It is unclear what vaping devices and ENDS modifications are used most frequently by AYAs who vape both nicotine and cannabis. METHODS: AYAs (aged 14-29) reporting ENDS use in the past 30 days were recruited via Qualtrics (N = 1,011). We conducted three multivariable logistic regression models examining differences in likelihood of: 1) vaping cannabis in the past 30 days; 2) mixing cannabis and nicotine liquids; and 3) using nicotine devices to vape cannabis; based on type of vaping device used most often, controlling for age, socio-economic status, gender, race, frequency of ENDS use, and other cannabis use. RESULTS: 40 % (n = 405) of AYAs reported vaping both nicotine and cannabis in the past 30 days. AYAs who used vape pens most often were more likely to have vaped cannabis concentrates in the past 30 days compared to individuals using disposable vapes (aOR = 2.72, 95 %CI = 1.75-4.21, p < 0.001). AYAs who used open systems most often (i.e., vape pens, mods, or e-hookah) were more likely than individuals using closed systems (i.e., disposable vapes, rechargeable pods or cigalikes) to combine nicotine and cannabis e-liquids (aOR = 2.03, 95 %CI = 1.43-2.89, p < 0.001) or use a nicotine device to vape cannabis (aOR = 1.66, 95 %CI = 1.17-2.34, p = 0.005). IMPLICATIONS: Co-use of cannabis and nicotine via similar devices, particularly vape pens and other open-systems, warrants collaborative regulatory efforts to mitigate co-use of both substances, with a particular need for increased regulation of cannabis vaping products.

Optimum tacrolimus trough levels for enhanced graft survival and safety in kidney transplantation: a retrospective multicenter real-world evidence study.

BACKGROUND: The current study aimed to determine the optimal tacrolimus trough levels for balancing graft survival and patient safety following kidney transplantation. MATERIALS AND METHODS: We conducted a retrospective cohort study involving 11,868 kidney transplant recipients from five medical centers. The association between tacrolimus exposures (periodic mean trough level, coefficient of variability, time in therapeutic range) and composite allograft outcome (de novo donor specific antibody, biopsy-proven rejection, kidney dysfunction, and graft failure), as well as safety outcomes (severe infection, cardiovascular events, malignancy, and mortality) were assessed. Data were sourced from Clinical Data Warehouses and analyzed using advanced statistical methods, including Cox marginal structural models with inverse probability treatment weighting. RESULTS: Tacrolimus levels of 5.0-7.9 ng/mL and 5.0-6.9 ng/mL during the 2-12 month and 12-72 month post-transplantation periods, respectively, were associated with reduced risks of composite allograft outcomes. During the first post-transplant year, the adjusted hazard ratios (aHR) for composite allograft outcomes were: 0.69 (95% CI 0.55-0.85, P<0.001) for 5.0-5.9 ng/mL; 0.81 (95% CI 0.67-0.98, P=0.033) for 6.0-6.9 ng/mL; and 0.73 (95% CI 0.60-0.89, P=0.002) for 7.0-7.9 ng/mL (compared to levels ≥8.0 ng/mL). For the 6-year composite outcomes, aHRs were 0.68 (95% CI 0.53-0.87, P=0.002) for 5.0-5.9 ng/mL and 0.65 (95% CI 0.50-0.85, P=0.001) for 6.0-6.9 ng/mL. These optimal ranges showed reduced rates of severe infection (6 y), malignancy (6 y), and mortality (1 y). CONCLUSION: This multicenter study provides robust evidence for optimal tacrolimus trough levels during the periods 2-12 and 12-72 months following kidney transplantation.

Modification of Electronic Nicotine Delivery Systems Among Adolescents and Young Adults.

OBJECTIVES: We assessed awareness and perceptions of, information sources about, and engagement in modifying electronic nicotine delivery systems (ENDS) among adolescents and young adults (AYAs). METHODS: AYAs (N = 1018) endorsing past-month ENDS use completed a survey on awareness and use of the following modifications: (1) refilling rechargeable cartridges/pods or (2) disposable pods, (3) rewicking or (4) recharging disposable pods, (5) modifying nicotine e-liquids (eg, changing propylene glycol/vegetable glycerin, nicotine), (6) combining nicotine and cannabis for simultaneous vaping, and (7) putting cannabis in ENDS designed for nicotine vaping. Logistic regression assessed how sources of information (eg, friends, social media, nonsocial media Web sites, vape shops) about and perceptions of ENDS modifications associated with ENDS modifications. RESULTS: Refilling (69.0% heard, 40.1% tried) and recharging the battery (66.4% heard, 35.8% tried) of disposable pods were most common. Friends (64.4%) and social media (46.7%) were the most common sources of information. Notable significant associations between information sources and modifications were: 1. nonsocial media Web sites and vape shops with rewicking and recharging disposable devices and modifying nicotine e-liquid; 2. nonsocial media Web sites with refilling rechargeable cartridges/pods and disposable pods; and 3. social media with recharging disposable devices and mixing nicotine and cannabis liquids. Perceptions of reduced harm and "coolness" were associated with various modifications. DISCUSSION: AYAs are aware of and modify ENDS for purposes unintended by manufacturers. ENDS policies should consider unintended ENDS use to safeguard public health. Prevention efforts should communicate about the potential harms of ENDS modifications.

Adolescents and Young Adults Use of Social Media and Following of e-Cigarette Influencers.

BACKGROUND: With high rates of both e-cigarette and social media use among adolescents and young adults (AYAs), social media influencers who promote e-cigarettes are particularly concerning but are understudied. We examined the association between AYAs' use of 11 different social media platforms (e.g. Facebook, Twitter, Instagram, TikTok, and YouTube) and exposure to social media e-cigarette influencers. OBJECTIVES: From November 2022 to February 2023, we conducted an online, US national survey of AYAs (14-29 years) who endorsed past-30-day e-cigarette use. We used binomial logistic regression to examine associations between the frequency of use of each social media platform and following e-cigarette influencers, controlling for age, sex, race, ethnicity, e-cigarette use frequency, and other tobacco and substance use (i.e., alcohol and cannabis). The model was stratified by adolescents (14-17 years; n = 293) and young adults (18-29 years; n = 654). RESULTS: The most frequently used social media platforms were Snapchat, TikTok and Instagram among adolescents, and YouTube, Instagram and TikTok among young adults. In adjusted models, following e-cigarette influencers was associated with more frequent use of TikTok (adjusted odds ratio [95% CI]; 1.33 [1.05, 1.68]) and Pinterest (1.18 [1.02, 1.38]) among adolescents, and more frequent use of Twitter (1.17 [1.06, 1.29]) among young adults. CONCLUSIONS: The use of different platforms was associated with exposure to e-cigarette influencers: TikTok and Pinterest among adolescents and Twitter among young adults. These findings can inform tobacco regulatory policy and social media platform restrictions of e-cigarette influencers on the platforms that are popular among AYAs.

E-cigarette dependence and cooling flavor use are linked among youth.

BACKGROUND: E-cigarette flavors that produce cooling sensations may reduce nicotine harshness and enhance appeal among youth. While previous research has shown that use of cooling flavors is associated with more frequent vaping among youth, it is unknown whether the same holds true for e-cigarette dependence. This study examines the relationship between cooling flavor use and e-cigarette dependence among youth accounting for vaping frequency. METHODS: In Fall 2022, a survey was conducted among Connecticut high school students to assess past-month nicotine e-cigarette use, ever use of cooling flavors, cooling flavor types (e.g., fruit-cooling), and e-cigarette dependence. Analyses were restricted to those with past-month nicotine and nicotine-free e-cigarette use and complete data (n=204). Multivariable linear regressions were run to examine the association between cooling flavor use and e-cigarette dependence, adjusting for demographics, e-cigarette use characteristics, and other tobacco product use. RESULTS: 78.4% of the sample used cooling e-cigarette flavors, with 55.0% using mint-cooling flavors and 52.5% using fruit-cooling flavors. Regression results observed that cooling flavor use was associated with higher e-cigarette dependence (ꞵ=1.53, SE=0.63, p=0.017), with those who used cooling flavors having higher e-cigarette dependence than those who did not (M=5.78 [SD=5.33] vs. 2.84 [3.19]). CONCLUSIONS: Our results suggest that cooling flavor use is significantly associated with e-cigarette dependence among youth. While regulations often target menthol flavor, tobacco control agencies should consider restricting any flavor that can produce cooling sensations, even if they are not traditional menthol products, as cooling flavors is associated with youth e-cigarette dependence.

Longitudinal long term follow up investigation on the carcinogenic impact of polyhexamethylene guanidine phosphate in rat models.

Polyhexamethylene guanidine phosphate (PHMG-p) is a major component in humidifier disinfectants, which cause life-threatening lung injuries. However, to our knowledge, no published studies have investigated associations between PHMG-p dose and lung damage severity with long-term follow-up. Therefore, we evaluated longitudinal dose-dependent changes in lung injuries using repeated chest computed tomography (CT). Rats were exposed to low (0.2 mg/kg, n = 10), intermediate (1.0 mg/kg, n = 10), and high (5.0 mg/kg, n = 10) doses of PHMG-p. All rats underwent repeated CT scans after 10 and 40 weeks following the first exposure. All CT images were quantitatively analyzed using commercial software. Inflammation/fibrosis and tumor counts underwent histopathological evaluation. In both radiological and histopathologic results, the lung damage severity increased as the PHMG-p dose increased. Moreover, the number, size, and malignancy of the lung tumors increased as the dose increased. Bronchiolar-alveolar hyperplasia developed in all groups. During follow-up, there was intergroup variation in bronchiolar-alveolar hyperplasia progression, although bronchiolar-alveolar adenomas or carcinomas usually increase in size over time. Thirty-three carcinomas were detected in the high-dose group in two rats. Overall, lung damage from PHMG-p and the number and malignancy of lung tumors were shown to be dose-dependent in a rat model using repeated chest CT scans during a long-term follow-up.

Using Computer Vision to Detect E-cigarette Content in TikTok Videos.

INTRODUCTION: Previous research has identified abundant e-cigarette content on social media using primarily text-based approaches. However, frequently used social media platforms among youth, such as TikTok, contain primarily visual content, requiring the ability to detect e-cigarette-related content across large sets of videos and images. This study aims to use a computer vision technique to detect e-cigarette-related objects in TikTok videos. AIMS AND METHODS: We searched 13 hashtags related to vaping on TikTok (eg, #vape) in November 2022 and obtained 826 still images extracted from a random selection of 254 posts. We annotated images for the presence of vaping devices, hands, and/or vapor clouds. We developed a YOLOv7-based computer vision model to detect these objects using 85% of extracted images (N = 705) for training and 15% (N = 121) for testing. RESULTS: Our model's recall value was 0.77 for all three classes: vape devices, hands, and vapor. Our model correctly classified vape devices 92.9% of the time, with an average F1 score of 0.81. CONCLUSIONS: The findings highlight the importance of having accurate and efficient methods to identify e-cigarette content on popular video-based social media platforms like TikTok. Our findings indicate that automated computer vision methods can successfully detect a range of e-cigarette-related content, including devices and vapor clouds, across images from TikTok posts. These approaches can be used to guide research and regulatory efforts. IMPLICATIONS: Object detection, a computer vision machine learning model, can accurately and efficiently identify e-cigarette content on a primarily visual-based social media platform by identifying the presence of vaping devices and evidence of e-cigarette use (eg, hands and vapor clouds). The methods used in this study can inform computational surveillance systems for detecting e-cigarette content on video- and image-based social media platforms to inform and enforce regulations of e-cigarette content on social media.

Benefits of statin therapy within a year after kidney transplantation.

Cardiovascular disease remains a leading cause of morbidity and mortality after kidney transplantation (KT). Although statins reduce cardiovascular risk and have renal benefits in the general population, their effects on KT recipients are not well-established. We studied the effects of early statin use (within 1-year post-transplantation) on long-term outcomes in 714 KT recipients from the Korean cohort study for outcome in patients with KT. Compared with the control group, statin group recipients were significantly older, had a higher body mass index, and had a higher prevalence of diabetes mellitus. During a median follow-up of 85 months, 74 graft losses occurred (54 death-censored graft losses and 20 deaths). Early statin use was independently associated with lower mortality (hazard ratio, 0.280; 95% confidence interval 0.111-0.703) and lower death-censored graft loss (hazard ratio, 0.350; 95% confidence interval 0.198-0.616). Statin therapy significantly reduced low-density lipoprotein cholesterol levels but did not decrease the risk of major adverse cardiovascular events. Biopsy-proven rejection and graft renal function were not significantly different between statin and control groups. Our findings suggest that early statin use is an effective strategy for reducing low-density lipoprotein cholesterol and improving patient and graft survival after KT.

Creatinine-cystatin C ratio and death with a functioning graft in kidney transplant recipients.

Death with a functioning graft is important cause of graft loss after kidney transplantation. However, little is known about factors predicting death with a functioning graft among kidney transplant recipients. In this study, we evaluated the association between post-transplant creatinine-cystatin C ratio and death with a functioning graft in 1592 kidney transplant recipients. We divided the patients into tertiles based on sex-specific creatinine-cystatin C ratio. Among the 1592 recipients, 39.5% were female, and 86.1% underwent living-donor kidney transplantation. The cut-off value for the lowest creatinine-cystatin C ratio tertile was 0.86 in males and 0.73 in females. The lowest tertile had a significantly lower 5-year patient survival rate and was independently associated with death with a functioning graft (adjusted hazard ratio 2.574, 95% confidence interval 1.339-4.950, P < 0.001). Infection was the most common cause of death in the lowest tertile group, accounting for 62% of deaths. A low creatinine-cystatin C ratio was significantly associated with an increased risk of death with a functioning graft after kidney transplantation.

Successful robotic kidney transplantation for surgeons with no experience in minimally invasive surgery: a single institution experience.

BACKGROUND: Robotic kidney transplantation (RKT) is a novel and welcomed innovation yielding good surgical outcomes. However, data on the feasibility and safety of performing RKT by surgeons with a lack of prior minimally invasive surgery (MIS) experience are limited. The authors aimed to evaluate the surgical and functional results of RKT and present the learning curves (LC) of RKT by a single surgeon with no prior experience in MIS. MATERIALS AND METHODS: This was a retrospective study of all RKT performed between November 2019 and April 2023 at Severance Hospital in Seoul, South Korea. The authors analyzed surgical and functional outcomes, as well as complication rates of RKT in comparison to open kidney transplantation (OKT). The authors evaluated LCs using the cumulative summation method to describe the number of cases associated with the competency of a single surgeon. RESULTS: A total of 50 patients who underwent RKT and 104 patients who underwent OKT were included in this study. In RKT group, the median surgical console time was 193 min (interquartile range, 172-222) and the median vascular anastomoses time was 38 min (35-44). Total operation time was 323 min (290-371) and rewarming time was 62.5 min (56.0-70.0) in RKT group compared to 210 min (190-239) and 25 min (21-30), respectively, in OKT group. Despite extended surgical durations with a robotic technique, both groups had comparable intraoperative and postoperative outcomes, as well as renal function. Estimated blood loss and post-transplant hospital stays were significantly lower in RKT group than in OKT group. LC analysis of RKT by the single surgeon revealed that surgical competence was achieved after 15 cases. CONCLUSION: Even if surgeons do not have prior experience with MIS, they can rapidly overcome the LC and safely perform RKT with adequate preparation and acquisition of basic robotic surgical techniques.

Clinical relevance of the living kidney donor profile index in Korean kidney transplant recipients.

BACKGROUND: The Living Kidney Donor Profile Index (LKDPI) was developed in the United States to predict graft outcomes based on donor characteristics. However, there are significant differences in donor demographics, access to transplantation, proportion of ABO incompatibility, and posttransplant mortality in Asian countries compared with the United States. METHODS: We evaluated the clinical relevance of the LKDPI score in a Korean kidney transplant cohort by analyzing 1860 patients who underwent kidney transplantation between 2000 and 2019. Patients were divided into three groups according to LKDPI score: <0, 1-19.9, and ≥20. RESULTS: During a median follow-up of 119 months, 232 recipients (12.5%) experienced death-censored graft loss, and 98 recipients (5.3%) died. High LKDPI scores were significantly associated with increased risk of death-censored graft loss independent of recipient characteristics (LKDPI 1-19.9: HR 1.389, 95% CI 1.036-1.863; LKDPI ≥20: HR 2.121, 95% CI 1.50-2.998). High LKDPI score was also significantly associated with increased risk of biopsy-proven acute rejection and impaired graft renal function. By contrast, overall patient survival rates were comparable among the LKDPI groups. CONCLUSION: High LKDPI scores were associated with an increased risk of death-censored graft loss, biopsy-proven acute rejection, and impaired graft renal function among a Korean kidney transplant cohort.

Content Analysis of YouTube Videos Related to E-Cigarettes and COVID-19.

BACKGROUND: E-cigarettes are frequently promoted on social media and portrayed in ways that are attractive to youth. While the COVID-19 pandemic significantly affected people's lives, less is known about how the pandemic influenced e-cigarette-related marketing and information on social media. This study examined how e-cigarettes were portrayed on youtube, one of the most popular social media platforms during the COVID-19 pandemic. METHODS: We searched for combinations of search terms related to e-cigarettes (e.g., "electronic cigarette" and "vape") and COVID-19 (e.g., "corona" and "COVID") in July of 2021. To be included in analyses, videos must be: uploaded after February 1, 2020, in English, related to e-cigarettes and COVID-19, and less than 30 min in length. We conducted a content analysis of included videos, coding for uploader characteristics, what e-cigarette products were showcased, and specific themes that intersected between e-cigarettes and COVID-19. RESULTS: We examined N = 307 videos and found that N = 220 (73.6%) discussed the health effects of e-cigarette use on COVID-19, followed by videos on how COVID-19 affects e-cigarette sales (N = 40, 12.9%), face mask-related videos (N = 16, 5.1%; e.g., vape tricks including masks) and instructional videos (N = 10, 3.2%; e.g., sanitizing vape devices during COVID-19). Instructional videos had the highest number of likes (Median = 23; IQR = 32) and comments (Median = 10; IQR = 7). CONCLUSIONS: Our findings support the need for continuous surveillance and research on novel vaping-related content in reaction to policies and events, such as the global pandemic. More research is needed to understand the impact of this content on young people's perceptions and use of e-cigarettes.

Social Media Use and Subsequent E-Cigarette Susceptibility, Initiation, and Continued Use Among US Adolescents.

INTRODUCTION: Social media has a large amount of e-cigarette content. Little is known about the associations between social media use and a wide range of e-cigarette use behaviors, including susceptibility, initiation, and continued use. We analyzed national data on US adolescents to assess these associations. METHODS: We used data on adolescents participating in the Population Assessment of Tobacco and Health (PATH) Study Wave 4 (2016-2018) and Wave 5 (2018-2019). We conducted 2 models: 1) a multinomial logistic regression on e-cigarette use susceptibility and use behaviors at Wave 5 by social media use at Wave 4 among adolescents who never used e-cigarettes at Wave 4 and 2) a binomial logistic regression on current e-cigarette use at Wave 5 by social media use at Wave 4 among adolescents who ever used e-cigarettes at Wave 4. RESULTS: Among adolescents who never used e-cigarettes at Wave 4 (n = 7,872), daily social media use (vs never) was associated with a higher likelihood of being susceptible to e-cigarette use (adjusted odds ratio [aOR] =1.46; 95% CI, 1.20-1.78), past e-cigarette use (aOR = 3.55; 95% CI, 2.49-5.06), and current e-cigarette use (aOR = 3.45; 95% CI, 2.38-5.02) at Wave 5. Among adolescents who ever used e-cigarettes at Wave 4 (n = 794), we found no significant association between social media use at Wave 4 and continued e-cigarette use at Wave 5. CONCLUSION: Our study found that social media use is associated with subsequent susceptibility to e-cigarette use and initiation but not with continued use of e-cigarettes among US adolescents. These findings suggest that understanding and addressing the association between social media and e-cigarette use is critical.

Vaping of Cannabis, Cannabidiol, and Synthetic Cannabis Among US Sexual Minority Youths.

This cross-sectional study investigates rates of vaping of cannabis, cannabidiol, and synthetic cannabis among US sexual minority youths.

The Promotion of Premium Cigars on Social Media.

INTRODUCTION: The health effect of premium cigar smoking is determined by patterns of use and perceptions, which are shaped by marketing messages. The tobacco industry uses brand-owned media promotion on social media to market its product. However, premium cigar brands' promotion of their products on social media is unknown. AIMS AND METHODS: Forty-seven premium cigar brands were reviewed. For each brand, we identified the social media accounts and examined the content of the 10 most recent posts of each social media platform to identify the marketing themes in July 2022. We also assessed the presence of age-gating and the dates of the posts. RESULTS: Of the 47 brands, 65% (n = 31) had Facebook and Instagram, 56% (n = 27) had Twitter, 21% (n = 10) had YouTube, and 17% (n = 8) had "other" (e.g. LinkedIn and Pinterest) accounts. Age-gating across these platforms ranged from 0% to 49%. Marketing themes identified from 981 social media posts included product features, alcohol, holidays, events and festivals, discounts and sweepstakes, taste, family, quality, lounges and clubs, culture, innovation, masculinity, and "other" (e.g. fundraising for charity and celebrity endorsement). CONCLUSIONS: Premium cigar brands are using brand-owned social media to promote their products using similar strategies (e.g. discounts and sweepstakes) used by other tobacco industries but also using novel themes (e.g. fundraising for charity, events and festivals) to enhance engagement. Ongoing comprehensive surveillance of premium cigars' marketing is needed on social media to inform marketing restrictions to protect public health, including priority populations such as youth. IMPLICATIONS: This study is the first to identify that premium cigar brands are promoting their brands and products on brand-owned social media, using diverse themes and strategies to engage and appeal to the public. Age gating of the promotional content on social media was low. Findings suggest that marketing restrictions to reduce the appeal of premium cigars among youth is needed to reduce tobacco-related harm.

Social media use and cannabis vaping initiation among US youth.

BACKGROUND: Youth cannabis vaping has increased in recent years, and there is growing evidence of cannabis vaping content on social media. This study investigated if social media use is associated with the initiation of cannabis vaping among US youth, using the youth dataset from Population Assessment of Tobacco and Health (PATH) Study Waves 4 (2016-2018) and 5 (2018-2019). METHODS: Using youth respondents who never vaped cannabis at Wave 4 (N=8357), we conducted a multivariable logistic regression analysis on initiation of cannabis vaping at Wave 5 (i.e., ever-vaped cannabis) by frequency of social media use, after controlling for covariates (e.g., sociodemographic, other tobacco and substance use). RESULTS: In this analytic sample, 66.5% reported daily social media use, 16.2% reported non-daily and 17.3% reported 'not having a social media account' or 'no social media use' at Wave 4. Further, 14.0% (n=1183) initiated cannabis vaping at Wave 5. In the multivariable logistic regression model, daily social media use (vs. never use; aOR=2.68; 95% CI=2.05, 3.49) and non-daily social media use (vs. never use; aOR=1.54; 95% CI=1.14, 2.09) at Wave 4 were associated with cannabis vaping initiation at Wave 5. CONCLUSIONS: Our evidence suggests that social media use by youth is associated with cannabis vaping initiation among youth in subsequent years, even after controlling for other risk factors. Consistent surveillance and regulation of cannabis vaping-related content on social media, as well as prevention efforts, including counter-messaging on social media about the potential harms of cannabis vaping, are critically needed.

Influence of User Profile Attributes on e-Cigarette-Related Searches on YouTube: Machine Learning Clustering and Classification.

Background: The proliferation of e-cigarette content on YouTube is concerning because of its possible effect on youth use behaviors. YouTube has a personalized search and recommendation algorithm that derives attributes from a user's profile, such as age and sex. However, little is known about whether e-cigarette content is shown differently based on user characteristics. Objective: The aim of this study was to understand the influence of age and sex attributes of user profiles on e-cigarette-related YouTube search results. Methods: We created 16 fictitious YouTube profiles with ages of 16 and 24 years, sex (female and male), and ethnicity/race to search for 18 e-cigarette-related search terms. We used unsupervised (k-means clustering and classification) and supervised (graph convolutional network) machine learning and network analysis to characterize the variation in the search results of each profile. We further examined whether user attributes may play a role in e-cigarette-related content exposure by using networks and degree centrality. Results: We analyzed 4201 nonduplicate videos. Our k-means clustering suggested that the videos could be clustered into 3 categories. The graph convolutional network achieved high accuracy (0.72). Videos were classified based on content into 4 categories: product review (49.3%), health information (15.1%), instruction (26.9%), and other (8.5%). Underage users were exposed mostly to instructional videos (37.5%), with some indication that more female 16-year-old profiles were exposed to this content, while young adult age groups (24 years) were exposed mostly to product review videos (39.2%). Conclusions: Our results indicate that demographic attributes factor into YouTube's algorithmic systems in the context of e-cigarette-related queries on YouTube. Specifically, differences in the age and sex attributes of user profiles do result in variance in both the videos presented in YouTube search results as well as in the types of these videos. We find that underage profiles were exposed to e-cigarette content despite YouTube's age-restriction policy that ostensibly prohibits certain e-cigarette content. Greater enforcement of policies to restrict youth access to e-cigarette content is needed.

Comparison of high-dose IVIG and rituximab versus rituximab as a preemptive therapy for de novo donor-specific antibodies in kidney transplant patients.

De novo donor-specific antibody (dnDSA) is associated with a higher risk of kidney graft failure. However, it is unknown whether preemptive treatment of subclinical dnDSA is beneficial. Here, we assessed the efficacy of high-dose intravenous immunoglobulin (IVIG) and rituximab combination therapy for subclinical dnDSA. An open-label randomized controlled clinical trial was conducted at two Korean institutions. Adult (aged ≥ 19 years) kidney transplant patients with subclinical class II dnDSA (mean fluorescence intensity ≥ 1000) were enrolled. Eligible participants were randomly assigned to receive rituximab or rituximab with IVIG at a 1:1 ratio. The primary endpoint was the change in dnDSA titer at 3 and 12 months after treatment. A total of 46 patients (24 for rituximab and 22 for rituximab with IVIG) were included in the analysis. The mean baseline estimated glomerular filtration rate was 66.7 ± 16.3 mL/min/1.73 m2. The titer decline of immune-dominant dnDSA at 12 months in both the preemptive groups was significant. However, there was no difference between the two groups at 12 months. Either kidney allograft function or proteinuria did not differ between the two groups. No antibody-mediated rejection occurred in either group. Preemptive treatment with high-dose IVIG combined with rituximab did not show a better dnDSA reduction compared with rituximab alone.Trial registration: IVIG/Rituximab versus Rituximab in Kidney Transplant With de Novo Donor-specific Antibodies (ClinicalTrials.gov Identifier: NCT04033276, first trial registration (26/07/2019).

Risk factors for late-onset Pneumocystis jirovecii pneumonia in liver transplant recipients.

OBJECTIVES: The risk factors for late-onset Pneumocystis jirovecii pneumonia (PCP) after liver transplantation (LT) have not been well studied. We aimed to analyze the clinical features preceding PCP in LT recipients that would guide individualized prophylaxis. METHODS: Among 742 patients who underwent LT and routine PCP prophylaxis from January 2009 through December 2019 at Severance Hospital, 27 patients developed PCP. We conducted a retrospective case-control study matching each patient with four controls and analyzed the risk factors for late-onset PCP. RESULTS: After 6 months, post-transplant PCP cases increased steadily with an overall incidence of 6.36 cases per 1000 patient-year. The PCP-related mortality was 37.0%. In the multivariate analyses, age at LT ≥65 years (odds ratio [OR], 13.305; 95% confidence interval [CI], 2.507-70.618; P = 0.002), cytomegalovirus infection (OR, 5.390; 95% CI, 1.602-18.132; P = 0.006), steroid pulse therapy (OR, 6.564; 95% CI, 1.984-21.719; P = 0.002), hepatocellular carcinoma recurrence (OR, 18.180; 95% CI, 3.420-96.636; P = 0.001), and lymphocytopenia (OR, 3.758; 95% CI, 1.176-12.013; P = 0.026) were independently associated with PCP. CONCLUSION: Late-onset PCP after routine prophylaxis after LT remains a lethal infection and is associated with age ≥65 years at LT, cytomegalovirus infection, steroid pulse therapy, hepatocellular carcinoma recurrence, and lymphocytopenia. Targeted prophylaxis considering these risk factors could improve the prevention of this potentially lethal complication.