How well do DSM-5 criteria measure alcohol use disorder in the general population of older Swedish adolescents? An item response theory analysis

BACKGROUND

This study assesses the psychometric properties of DSM-5 criteria of AUD in older Swedish adolescents using item response theory models, focusing specifically on the precision of the scale at the cut-offs for mild, moderate, and severe AUD.

METHODS

Data from the second wave of Futura01 was used. Futura01 is a nationally representative cohort study of Swedish people born 2001 and data for the second wave was collected when participants were 17/18 years old. This study included only participants who had consumed alcohol during the past 12 months (n = 2648). AUD was measured with 11 binary items. A 2-parameter logistic item response theory model (2PL) estimated the items' difficulty and discrimination parameters.

RESULTS

31.8% of the participants met criteria for AUD. Among these, 75.6% had mild AUD, 18.3% had moderate, and 6.1% had severe AUD. A unidimensional AUD model had a good fit and 2PL models showed that the scale measured AUD over all three cut-offs for AUD severity. Although discrimination parameters ranged from moderate (1.24) to very high (2.38), the more commonly endorsed items discriminated less well than the more difficult items, as also reflected in less precision of the estimates at lower levels of AUD severity. The diagnostic uncertainty was pronounced at the cut-off for mild AUD.

CONCLUSION

DSM-5 criteria measure AUD with better precision at higher levels of AUD severity than at lower levels. As most older adolescents who fulfil an AUD diagnosis are in the mild category, notable uncertainties are involved when an AUD diagnosis is set in this group.

Different measures of alcohol use as predictors of DSM-5 alcohol use disorder among adolescents - A cohort study from Sweden

BACKGROUND AND AIMS

This study addresses a significant gap in existing research by investigating the longitudinal relationship between various measures of alcohol use and the development of alcohol use disorders (AUDs) in a cohort of Swedish adolescents.

METHODS

A prospective longitudinal survey was conducted on 3999 adolescents in Sweden who were in 9th grade in 2017 and were followed up in 2019. Baseline assessments included lifetime alcohol use, recent use (past 30 days), risky drinking (AUDIT-C), and heavy episodic drinking (HED). Follow-up assessments comprised eleven items measuring DSM-5 AUD criteria. The study explores prospective associations between these diverse alcohol use measures and the occurrence of AUD, while also calculating population attributable fractions (PAF).

FINDINGS

The proportion of alcohol consumers who met the criteria for AUD at follow-up was 31.8%. All baseline measures of alcohol use exhibited associations with subsequent AUD. Notably, the HED group demonstrated the highest prevalence of AUD at 51.4% (p<.001). However, when calculating PAFs, any lifetime alcohol use emerged as the most substantial contributor, accounting for 10.8% of all subsequent AUD cases.

CONCLUSIONS

This study underscores that alcohol use during mid-adolescence heightens the risk of developing AUD in late adolescence. Among the various measures, heavy episodic drinking presents the highest risk for later AUD. From a public health perspective, preventing any alcohol use emerges as the most effective strategy to mitigate the population-level burden of disease of AUD.

Psychosocial correlates of drinking transitions: A longitudinal study among adolescents in Sweden

INTRODUCTION

Non-drinkers have been shown in older studies to have poorer mental health and social life compared to their alcohol-using counterparts. Given the profound decline in adolescent drinking observed in most high-income countries, this pattern may have changed. This study explores drinking transitions and examines psychosocial factors among adolescents by longitudinal drinking status.

METHODS

Data were based on two waves of a prospective longitudinal nationwide study (n = 4018). The first wave (T1) of data was collected in 2017 (age 15/16) and the second wave (T2) was in 2019 (age 17/18). Respondents were asked about their past year drinking status, general health, psychosomatic problems, psychiatric medication, school enjoyment, emotional symptoms, peer relationship problems, prosocial ability, friendships satisfaction and satisfaction with relation to mother/father. Comparisons by mean values were assessed and multinomial logistic regressions were used to examine associations.

RESULTS

Abstainers and later drinkers differed significantly from early drinkers on 9/10 factors respectively at T1. Fewer psychosomatic problems, less psychiatric medication, higher school enjoyment, more emotional symptoms, higher parental relationship satisfaction, more peer problems and lower friendships satisfaction at T1 were associated with abstaining and/or later drinking. All factors were more strongly associated with abstaining. School enjoyment predicted abstaining but not later drinking.

DISCUSSION AND CONCLUSIONS

Longitudinal drinking status relates to small to moderate systematic psychosocial differences. Adolescents with better mental health, more content relationships with parents and lower friendships satisfaction are more often abstainers. Those generally worse off are more likely early drinkers but they also have better friendships.

The feasibility of an exercise intervention after robotic-assisted radical cystectomy for urinary bladder cancer, prior to the CanMoRe trial

BACKGROUND

Complications after radical cystectomy for urinary bladder cancer are common. Physical activity after surgery is thought to reduce complications. However, patients with urinary bladder cancer have low levels of physical activity, and interventions supporting physical exercise are needed. This study aimed to evaluate the feasibility of a physical exercise intervention in primary health care. One of the aims of the larger clinical trial will be to reduce complications.

METHODS

Patients with urinary bladder cancer and who were scheduled for a robotic-assisted radical cystectomy were recruited from Karolinska University Hospital, between February and May 2019. The patients had to be mobile, understand Swedish, and live in Stockholm. The exercise programme was conducted at one primary health care setting over 12 weeks. The exercise programme included supervised aerobic and strengthening exercises, which were performed twice a week, as well as daily walks. Feasibility was measured with process feasibility, including eligibility criteria, adherence, and acceptability, and scientific feasibility, including the ability of outcomes to indicate change, safety, and progression in the exercise programme.

RESULTS

Ten patients with a median age of 70 years (min 53-max 86) were included. Adherence to all parts of the intervention was not feasible because of patients' postoperative complications, resulting in dropouts. For the patients who took part in the exercise programme, adherence and acceptability for the exercise period were feasible, but the 6-min walk test was not feasible at discharge from the hospital. Physiotherapists in the primary health care setting perceived the process as feasible. Moreover, the ability of outcomes to indicate change and progression in the exercise programme was feasible, meanwhile no adverse events were registered.

CONCLUSIONS

The exercise intervention was feasible for the patients that took part in the exercise programme, with respect to safety and progression through the exercise programme. Furthermore, this study suggests that some improvements needed to be implemented in the process, prior to the upcoming randomised controlled trial.

Combination of separation and degradation methods after PFAS soil washing

The current study evaluated a three-stage treatment to remediate PFAS-contaminated soil. The treatment consisted of soil washing, foam fractionation (FF), and electrochemical oxidation (EO). The possibility of replacing the third stage, i.e., EO, with an adsorption process was also assessed. The contamination in the studied soils was dominated by perfluorooctane sulfonate (PFOS), with a concentration of 760 and 19 μg kg-1 in soil I and in soil II, accounting for 97 % and 70 % of all detected per-and polyfluoroalkyl substances (PFAS). Before applying a pilot treatment of soil, soil washing was performed on a laboratory scale, to evaluate the effect of soil particle size, initial pH and a liquid-to-soil ratio (L/S) on the leachability of PFAS. A pilot washing system generated soil leachate that was subsequently treated using FF and EO (or adsorption) and then reused for soil washing. The results indicated that the leaching of PFAS occurred easier in 0.063-1 mm particles than in the soil particles having a size below 0.063 mm. Both alkaline conditions and a continual replacement of the leaching solution increased the leachability of PFAS. The analysis using one-way ANOVA showed no statistical difference in means of PFOS washed out in laboratory and pilot scales. This allowed estimating twenty washing cycles using 120 L water to reach 95 % PFOS removal in 60 kg soil. The aeration process removed 95-99 % PFOS in every washing cycle. The EO and adsorption processes achieved similar results removing up to 97 % PFOS in concentrated soil leachate. The current study demonstrated a multi-stage treatment as an effective and cost-efficient method to permanently clean up PFAS-contaminated soil.

Immunotoxic, genotoxic, and endocrine disrupting impacts of polyamide microplastic particles and chemicals

Due to their exceptional properties and cost effectiveness, polyamides or nylons have emerged as widely used materials, revolutionizing diverse industries, including industrial 3D printing or additive manufacturing (AM). Powder-based AM technologies employ tonnes of polyamide microplastics to produce complex components every year. However, the lack of comprehensive toxicity assessment of particulate polyamides and polyamide-associated chemicals, especially in the light of the global microplastics crisis, calls for urgent action. This study investigated the physicochemical properties of polyamide-12 microplastics used in AM, and assessed a number of toxicity endpoints focusing on inflammation, immunometabolism, genotoxicity, aryl hydrocarbon receptor (AhR) activation, endocrine disruption, and cell morphology. Specifically, microplastics examination by means of field emission scanning electron microscopy revealed that work flow reuse of material created a fraction of smaller particles with an average size of 1-5 µm, a size range readily available for uptake by human cells. Moreover, chemical analysis by means of gas chromatography high-resolution mass spectrometry detected several polyamide-associated chemicals including starting material, plasticizer, thermal stabilizer/antioxidant, and migrating slip additive. Even if polyamide particles and chemicals did not induce an acute inflammatory response, repeated and prolonged exposure of human primary macrophages disclosed a steady increase in the levels of proinflammatory chemokine Interleukin-8 (IL-8/CXCL-8). Moreover, targeted metabolomics disclosed that polyamide particles modulated the kynurenine pathway and some of its key metabolites. The p53-responsive luciferase reporter gene assay showed that particles per se were able to activate p53, being indicative of a genotoxic stress. Polyamide-associated chemicals triggered moderate activation of AhR and elicited anti-androgenic activity. Finally, a high-throughput and non-targeted morphological profiling by Cell Painting assay outlined major sites of bioactivity of polyamide-associated chemicals and indicated putative mechanisms of toxicity in the cells. These findings reveal that the increasing use of polyamide microplastics may pose a potential health risk for the exposed individuals, and it merits more attention.

Is there a gender paradox in the association between conduct problems and cannabis use? A cohort-study among Swedish adolescents

INTRODUCTION

Conduct problems (CP) predict cannabis use prospectively but the research is mixed as to whether this association is stronger among girls. A stronger association among girls would suggest a 'gender paradox' as both CP and cannabis use is less common in this group. This study aimed to assess whether the longitudinal association between CP and cannabis use in Swedish adolescents is stronger among girls.

METHODS

Data from two waves of a nationally representative cohort study of Swedish adolescents born in 2001 were used. Baseline measurements were collected in 9th grade (at age 15-16) and follow-up measures at 11th grade (at age 17-18).

RESULTS

CP at baseline were significantly associated with cannabis use at follow-up adjusted for hyperactivity problems, emotional problems, socio-demographics, parental monitoring, school grades and truancy at baseline (odds ratio [OR] 1.14, 95% confidence interval [CI] 1.06-1.24) but not when also adjusting for substance use at baseline. Boys were more likely to have used cannabis during the past year, even when controlling for prior substance use (OR 2.29, 95% CI 1.76-2.98). The association between CP and cannabis use was significantly weaker for boys (OR 0.83, 95% CI 0.72-0.95 in the fully adjusted model). The predicted probability of cannabis use was stable at 0.13 for boys across levels of CP, but ranged from 0.05 to 0.16 for girls.

DISCUSSION AND CONCLUSION

The longitudinal association between CP and cannabis use was stronger among girls. The findings are indicative of a 'gender paradox' in the association between CP and cannabis use.

Further Insight into Extractable (Organo)fluorine Mass Balance Analysis of Tap Water from Shanghai, China

The ubiquitous occurrence of per- and polyfluoroalkyl substances (PFAS) and the detection of unexplained extractable organofluorine (EOF) in drinking water have raised growing concerns. A recent study reported the detection of inorganic fluorinated anions in German river systems, and therefore, in some samples, EOF may include some inorganic fluorinated anions. Thus, it might be more appropriate to use the term "extractable fluorine (EF) analysis" instead of the term EOF analysis. In this study, tap water samples (n = 39) from Shanghai were collected to assess the levels of EF/EOF, 35 target PFAS, two inorganic fluorinated anions (tetrafluoroborate (BF4-) and hexafluorophosphate (PF6-)), and novel PFAS through suspect screening and potential oxidizable precursors through oxidative conversion. The results showed that ultra-short PFAS were the largest contributors to target PFAS, accounting for up to 97% of ΣPFAS. To the best of our knowledge, this was the first time that bis(trifluoromethanesulfonyl)imide (NTf2) was reported in drinking water from China, and p-perfluorous nonenoxybenzenesulfonate (OBS) was also identified through suspect screening. Small amounts of precursors that can be oxidatively converted to PFCAs were noted after oxidative conversion. EF mass balance analysis revealed that target PFAS could only explain less than 36% of EF. However, the amounts of unexplained extractable fluorine were greatly reduced when BF4- and PF6- were included. These compounds further explained more than 44% of the EF, indicating the role of inorganic fluorinated anions in the mass balance analysis.

The feasibility of using a digital tool to enhance mobilisation following abdominal cancer surgery-a non-randomised controlled trial

BACKGROUND

Early mobilisation is strongly recommended following abdominal cancer surgery, but evidence on how to structure early mobilisation to improve outcomes and support patient adherence is lacking. Pedatim® (Phystec) is a novel digital tool designed to support mobilisation in hospital settings using prescribed activities and goals on a tablet. The aim of this study was to evaluate the feasibility of the Pedatim tablet to enhance mobilisation following abdominal cancer surgery.

METHODS

In a non-randomised feasibility trial design, participants were recruited between January and May 2022 at Karolinska University Hospital, Sweden. Participants used a Pedatim tablet from postoperative day 1 (POD 1) until hospital discharge. The primary objective was to evaluate process feasibility, regarding recruitment, compliance, and acceptability. Recruitment was measured by percentage of available patients included, eligibility criteria sufficiency, and number of dropouts. Compliance was measured by number of patients using versus not using the board. Acceptability was measured using the System Usability Scale. The secondary objective was to evaluate scientific feasibility, defined as an indication of treatment effects where physical activity was assessed using an activPAL accelerometer. Unforeseen events relating to the tablet were also registered.

RESULTS

Based on predetermined feasibility criteria, the overall study design was determined to be feasible regarding recruitment as 69% accepted participation (n = 20), compliance was 95%, and the acceptability mean score was high (77/100). Eligibility criteria were not feasible as 79% (n = 108) of available patients were excluded. The intervention was determined to be scientifically feasible, mean steps per day increased from 623 (SD 766) to 1823 (SD 1446), and mean sit-to-stand transitions per day increased from 11 (SD 8) to 29 (SD 12) POD 1-4. Technical issues emerged, highlighting the need for available technical support and "user champions" among healthcare professionals on the ward.

CONCLUSIONS

Using the Pedatim tablet to enhance mobilisation following abdominal cancer surgery was deemed feasible, but a randomised controlled trial is needed to determine the tool's effectiveness. The study process was determined to be feasible with revisions of the eligibility criteria needed before a future trial. Involving healthcare professionals and providing available technical support are important for future implementation.

Stability and Change in Substance Use Among Swedish Adolescents: A Latent Transition Analysis

Background: Research is needed on how substance use patterns develop over time in the general adolescent population. This knowledge is crucial in calibrating prevention and other interventions. Method: The study concerns use of cigarettes, alcohol, and cannabis in a nationally representative cohort of Swedish adolescents (n = 3999). Two waves (9th and 11th school grade) from the Futura01 study were analyzed using latent transition analysis (LTA) and multinomial regression analysis. Results: Four substance use patterns, were identified, ranging from Non-user, Alcohol experienced, Alcohol User to Co-user of cigarettes, alcohol, and cannabis. Statuses thus conveyed a continuum from no use to more advanced use. Half of the individuals remained in their original status between time-points, and half transitioned, most often one step on the continuum. Alcohol user was the most stable status over time (0.78), and the Non-user status the least (0.36). The probability of remaining in the Alcohol experienced status was 0.57, and 0.45 for the Co-user status. There was a low probability of transitioning from alcohol to cannabis use. Females were more likely to belong to Alcohol experienced and males to Co-user statuses, but these associations weakened over time. Conclusions: The study identified transitions across substance use statuses between time-points. These usually concerned different levels of alcohol use, and not into more advanced substance use that included the illegal substance cannabis. The study corroborates that young Swedes belong to a "sober" generation and usually do not transition from legal into illegal substance use during late adolescence, though with some gender differences.

Genomic characterisation of hormone receptor-positive breast cancer arising in very young women

BACKGROUND

Very young premenopausal women diagnosed with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+HER2-) early breast cancer (EBC) have higher rates of recurrence and death for reasons that remain largely unexplained.

PATIENTS AND METHODS

Genomic sequencing was applied to HR+HER2- tumours from patients enrolled in the Suppression of Ovarian Function Trial (SOFT) to determine genomic drivers that are enriched in young premenopausal women. Genomic alterations were characterised using next-generation sequencing from a subset of 1276 patients (deep targeted sequencing, n = 1258; whole-exome sequencing in a young-age, case-control subsample, n = 82). We defined copy number (CN) subgroups and assessed for features suggestive of homologous recombination deficiency (HRD). Genomic alteration frequencies were compared between young premenopausal women (<40 years) and older premenopausal women (≥40 years), and assessed for associations with distant recurrence-free interval (DRFI) and overall survival (OS).

RESULTS

Younger women (<40 years, n = 359) compared with older women (≥40 years, n = 917) had significantly higher frequencies of mutations in GATA3 (19% versus 16%) and CN amplifications (CNAs) (47% versus 26%), but significantly lower frequencies of mutations in PIK3CA (32% versus 47%), CDH1 (3% versus 9%), and MAP3K1 (7% versus 12%). Additionally, they had significantly higher frequencies of features suggestive of HRD (27% versus 21%) and a higher proportion of PIK3CA mutations with concurrent CNAs (23% versus 11%). Genomic features suggestive of HRD, PIK3CA mutations with CNAs, and CNAs were associated with significantly worse DRFI and OS compared with those without these features. These poor prognostic features were enriched in younger patients: present in 72% of patients aged <35 years, 54% aged 35-39 years, and 40% aged ≥40 years. Poor prognostic features [n = 584 (46%)] versus none [n = 692 (54%)] had an 8-year DRFI of 84% versus 94% and OS of 88% versus 96%. Younger women (<40 years) had the poorest outcomes: 8-year DRFI 74% versus 85% and OS 80% versus 93%, respectively.

CONCLUSION

These results provide insights into genomic alterations that are enriched in young women with HR+HER2- EBC, provide rationale for genomic subgrouping, and highlight priority molecular targets for future clinical trials.

A Novel Nanosafety Approach Using Cell Painting, Metabolomics, and Lipidomics Captures the Cellular and Molecular Phenotypes Induced by the Unintentionally Formed Metal-Based (Nano)Particles

Additive manufacturing (AM) or industrial 3D printing uses cutting-edge technologies and materials to produce a variety of complex products. However, the effects of the unintentionally emitted AM (nano)particles (AMPs) on human cells following inhalation, require further investigations. The physicochemical characterization of the AMPs, extracted from the filter of a Laser Powder Bed Fusion (L-PBF) 3D printer of iron-based materials, disclosed their complexity, in terms of size, shape, and chemistry. Cell Painting, a high-content screening (HCS) assay, was used to detect the subtle morphological changes elicited by the AMPs at the single cell resolution. The profiling of the cell morphological phenotypes, disclosed prominent concentration-dependent effects on the cytoskeleton, mitochondria, and the membranous structures of the cell. Furthermore, lipidomics confirmed that the AMPs induced the extensive membrane remodeling in the lung epithelial and macrophage co-culture cell model. To further elucidate the biological mechanisms of action, the targeted metabolomics unveiled several inflammation-related metabolites regulating the cell response to the AMP exposure. Overall, the AMP exposure led to the internalization, oxidative stress, cytoskeleton disruption, mitochondrial activation, membrane remodeling, and metabolic reprogramming of the lung epithelial cells and macrophages. We propose the approach of integrating Cell Painting with metabolomics and lipidomics, as an advanced nanosafety methodology, increasing the ability to capture the cellular and molecular phenotypes and the relevant biological mechanisms to the (nano)particle exposure.

Exploring the Link between ADHD and Cannabis Use in Swedish Ninth Graders: The Role of Conduct Problems and Sensation-Seeking

Background: Attention deficit hyperactivity disorder (ADHD) has in several studies been linked to substance use, including cannabis use. However, crucial gaps remain regarding how to understand this association. Analyzing the association between ADHD and substance use is complicated because of a pronounced overlap between ADHD, conduct problems, and traits such as sensation-seeking. Objectives: Using data from a large and nationally representative study among Swedish adolescents, this study explored the role of conduct problems, but also of sensation-seeking, in accounting for the association between ADHD and cannabis use. Results: There was a notable association between ADHD and cannabis use that was attenuated when conduct problems were controlled for. The association between cannabis use and conduct problems, in turn, was attenuated when sensation-seeking was controlled for. Individuals with both ADHD and conduct problems were more likely to have used cannabis than individuals with ADHD only, but not compared with individuals with conduct problems only. Conclusions: Whereas conduct problems largely explain the link between ADHD and cannabis use, sensation-seeking seems to account for the association between conduct problems and cannabis use.

Self-interpellation in narratives about craving: Multiple and unitary selves

The concept of addiction seeks to explain why people act contrary to their own best interest. At the centre stage of addiction discourse is craving, conceptualised as a strong urge to use substances. This article analyses how talk therapies such as relapse prevention and self-help groups shape identity constructions and understandings of craving among clients. Drawing upon interviews with individuals who have engaged in talk therapies in Sweden, we analyse how craving is made up through 'self-interpellation', that is, personal narratives about past, present or future thoughts, feelings and actions. The main 'self-interpellation' included multiple selves, where craving was elided by the true self and only felt by the inauthentic self. Less dominant were narratives which drew on a unitary self that remained stable over time and had to fight craving. The notion of multiple selves appeared as a master narrative that the participants were positioned by in their identity constructions. We conclude that this multiplicity seems ontologically demanding for people who try to recover from substance use problems. A demystification of craving, in which neither substance effects nor malfunctioning brains are blamed for seemingly irrational thoughts and actions, may reduce the stigmatisation of those who have developed habitual substance use.

Risk factors for substance use in Swedish adolescents: A study across substances and time points

Aim: The public health model for prevention of disease and disorder has been influential in informing interventions regarding substance use. While a number of risk factors within this model have been found to predict substance use, few studies have explored the associations across substances, at different time points and in the same individuals. The aim of this study was to test this model across legal and illegal substance use among adolescents, and to identify potential changes in associations over time. Methods: Data from two waves of a nationally representative cohort study among Swedish adolescents were used. Baseline data were collected in 2017 (9th grade) with a follow-up in 2019 (11th grade). Using modified Poisson regression analyses, we explored cross-sectional associations between factors from different domains and prevalence of cigarette use, binge-drinking and illegal drug use at both baseline and follow-up. Results: The results in part supported the public health model. Substance use was predicted by factors within the family, school and the individual/peer domain, but several associations were not statistically significant. The only consistent risk factors across substances and time points were lack of parental monitoring, truancy and minor criminal activities. Conclusion: Despite widely different prevalence rates across substances, some risk factors were consistently associated with adolescent substance use. Nonetheless, the findings challenge the assumption that risk factors are stable over adolescence. They suggest a need for flexible prevention interventions spanning across substances and legal boundaries of substances, but also over domains to reflect the heterogenous needs of adolescents.

Particle Safety Assessment in Additive Manufacturing: From Exposure Risks to Advanced Toxicology Testing

Additive manufacturing (AM) or industrial three-dimensional (3D) printing drives a new spectrum of design and production possibilities; pushing the boundaries both in the application by production of sophisticated products as well as the development of next-generation materials. AM technologies apply a diversity of feedstocks, including plastic, metallic, and ceramic particle powders with distinct size, shape, and surface chemistry. In addition, powders are often reused, which may change the particles’ physicochemical properties and by that alter their toxic potential. The AM production technology commonly relies on a laser or electron beam to selectively melt or sinter particle powders. Large energy input on feedstock powders generates several byproducts, including varying amounts of virgin microparticles, nanoparticles, spatter, and volatile chemicals that are emitted in the working environment; throughout the production and processing phases. The micro and nanoscale size may enable particles to interact with and to cross biological barriers, which could, in turn, give rise to unexpected adverse outcomes, including inflammation, oxidative stress, activation of signaling pathways, genotoxicity, and carcinogenicity. Another important aspect of AM-associated risks is emission/leakage of mono- and oligomers due to polymer breakdown and high temperature transformation of chemicals from polymeric particles, both during production, use, and in vivo, including in target cells. These chemicals are potential inducers of direct toxicity, genotoxicity, and endocrine disruption. Nevertheless, understanding whether AM particle powders and their byproducts may exert adverse effects in humans is largely lacking and urges comprehensive safety assessment across the entire AM lifecycle—spanning from virgin and reused to airborne particles. Therefore, this review will detail: 1) brief overview of the AM feedstock powders, impact of reuse on particle physicochemical properties, main exposure pathways and protective measures in AM industry, 2) role of particle biological identity and key toxicological endpoints in the particle safety assessment, and 3) next-generation toxicology approaches in nanosafety for safety assessment in AM. Altogether, the proposed testing approach will enable a deeper understanding of existing and emerging particle and chemical safety challenges and provide a strategy for the development of cutting-edge methodologies for hazard identification and risk assessment in the AM industry.

The factor structure of the Strength and Difficulties Questionnaire in a national sample of Swedish adolescents: Comparing 3 and 5-factor models

The Strength and Difficulties Questionnaire (SDQ) is one of the most common screening instruments for emotional and behavioral problems in children and adolescents. Although exploratory factor analyses support the originally proposed 5-factor structure of SDQ as well as a 3-factor model, the evidence from confirmatory factor analyses is more mixed. Some of the difficulties items in SDQ are positively worded and it has been proposed that this leads to method effects, i.e. these items share variance that is due to the method used rather than to a substantive construct. Also, there seems to be minor factors in some subscales. This study tests a series of 3- and 5- factor models pertaining to the factor structure of SDQ, also considering method effects and minor factors. The sample consists of a nationally representative cohort of Swedish adolescents born in 2001 (n = 5549). Results show a relatively better fit of the 5-factor model compared with the 3-factor model although neither of these had a satisfactory fit. Model fit was improved when specifying cross-loadings of the positively worded difficulties items on the prosocial scale as well as minor factors on the hyperactivity scale. Although no model provided a completely satisfactory fit to the data, the results show that the 5-factor model performs better than the 3-factor model and has an acceptable fit. We conclude that for the purposes of epidemiological research, SDQ has acceptable factorial validity, provided that researchers consider method effects and minor factors.

Reasons Not to Drink Alcohol among 9th Graders in Sweden

AIM

Alcohol is one of the leading contributors to the disease burden among young people. Drinking motives are one of the strongest factors influencing drinking behaviors among youth, yet we know little about reasons for why young people do not drink. The aim of the present study is to examine reasons for not drinking in a nationally representative sample of Swedish youth.

DATA AND METHODS

Data from a survey of a nationally representative sample of students in year 9 (15-16 years old) was used. Data was collected in 2017 and the total sample comprise 5549 respondents. Ten items measured reasons not to drink alcohol. Comparisons were made between drinkers and nondrinkers in endorsement of the reasons for not drinking. A multivariable logistic regression model was fitted to examine the relative importance of the different reasons.

RESULTS

That alcohol is bad for health and parents disapproval of drinking was the most commonly endorsed reasons both among drinkers and nondrinkers. The multivariable analysis showed that the strongest association with being a nondrinker was found for "Alcohol tastes horrible" (OR 2.995), "I have religious reasons for not drinking" (OR 2.775), "People who drink lose control in an unpleasant way" (OR 2.460) and "Drinking is too likely to lead to serious accidents" (OR 2.458).

DISCUSSION AND CONCLUSIONS

Harm avoidance and religious reasons are the most important reasons not to drink among Swedish youth. Future research should examine how different reasons predict abstinence.

An Explainable Machine Learning Model for Material Backorder Prediction in Inventory Management

Global competition among businesses imposes a more effective and low-cost supply chain allowing firms to provide products at a desired quality, quantity, and time, with lower production costs. The latter include holding cost, ordering cost, and backorder cost. Backorder occurs when a product is temporarily unavailable or out of stock and the customer places an order for future production and shipment. Therefore, stock unavailability and prolonged delays in product delivery will lead to additional production costs and unsatisfied customers, respectively. Thus, it is of high importance to develop models that will effectively predict the backorder rate in an inventory system with the aim of improving the effectiveness of the supply chain and, consequentially, the performance of the company. However, traditional approaches in the literature are based on stochastic approximation, without incorporating information from historical data. To this end, machine learning models should be employed for extracting knowledge of large historical data to develop predictive models. Therefore, to cover this need, in this study, the backorder prediction problem was addressed. Specifically, various machine learning models were compared for solving the binary classification problem of backorder prediction, followed by model calibration and a post-hoc explainability based on the SHAP model to identify and interpret the most important features that contribute to material backorder. The results showed that the RF, XGB, LGBM, and BB models reached an AUC score of 0.95, while the best-performing model was the LGBM model after calibration with the Isotonic Regression method. The explainability analysis showed that the inventory stock of a product, the volume of products that can be delivered, the imminent demand (sales), and the accurate prediction of the future demand can significantly contribute to the correct prediction of backorders.

Normalization of Non-Drinking? Health, School Situation and Social Relations among Swedish Ninth Graders That Drink and Do Not Drink Alcohol

Alcohol consumption is a major contributor to the disease burden among adolescents. The adolescent alcohol abstainer is still often depicted as problematic in the research literature and in prominent theoretical frameworks. However, over the past two decades, there has been a marked trend of declining youth drinking in Sweden. The declining trend has led to a shift in the majority behaviour of youth, from drinking to non-drinking. It is plausible that this trend has also shifted the position of non-drinkers. This paper examines the position of non-drinkers in a nationally representative sample of Swedish adolescents. A survey was carried out in 2017 in 500 randomly selected schools. A total of 5549 respondents (15-16-year-olds) agreed to participate and answered the questionnaire. A minority (42.8%) had consumed alcohol during their lifetime. The results show that non-drinkers had better health and school performance when compared to drinkers. The results also showed that there were no differences in the social position between non-drinkers and drinkers. These findings are new and indicate a changed position of non-drinkers among Swedish adolescents. With non-drinking being the majority behaviour among Swedish adolescents this seems to have shifted the position of non-drinkers. There is a need for research on the long-term importance of not drinking during adolescence.

Accuracy of estimating left ventricular ejection fraction in clinical routine. A SWEDEHEART registry validation study

Objective

Patients admitted to Swedish hospitals with myocardial infarction (MI) are reported to the nationwide Swedish registry for MI (SWEDEHEART). During hospital stay an echocardiography is routinely performed, and left ventricular ejection fraction (LVEF) is assessed according to the clinical praxis. LVEF is categorized as normal (&gt;50%) or mild, moderate or severely impaired (40–49%, 30–39% and &lt;30%, respectively) and reported to the registry by the treating center. The purpose of this study was to validate the reported LVEF assessments against independent echocardiography re-evaluation as this has never previously been done.

Methods

A random sample of 130 patient from three different hospitals were included. LVEF re-evaluation was performed by two independent reviewers using the modified biplane Simpson method and their mean LVEF was compared to the SWEDEHEART LVEF. Agreement between reported and re-evaluated LVEF was assessed using Gwet's AC2 statistics.

Results

Analysis showed good agreement between reported and reevaluated LVEF (AC2: 0.76 [95% CI 0.69–0.84]). The LVEF re-evaluations corresponded with registry reported categorized LVEF in 66.0% of cases. In 25.4% of cases the SWEDEHEART LVEF was lower than re-evaluated LVEF. The opposite relation was found in 8.6% of cases (p&lt;0.005).

Conclusion

Independent validation of SWEDEHEART-reported LVEF shows an overall good agreement with the re-evaluated LVEF. However, a tendency to underestimation of LVEF was observed in patients with impaired LV systolic function, in whom the reported assessment of LVEF should be interpreted more cautiously.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Selanders Stiftelse

Continuous versus intermittent extended adjuvant letrozole for breast cancer: final results of randomized phase III SOLE (Study of Letrozole Extension) and SOLE Estrogen Substudy

BACKGROUND

Late recurrences in postmenopausal women with hormone receptor-positive breast cancers remain an important challenge. Avoidance or delayed development of resistance represents the main objective in extended endocrine therapy (ET). In animal models, resistance was reversed with restoration of circulating estrogen levels during interruption of letrozole treatment. This phase III, randomized, open-label Study of Letrozole Extension (SOLE) studied the effect of extended intermittent letrozole treatment in comparison with continuous letrozole. In parallel, the SOLE estrogen substudy (SOLE-EST) analyzed the levels of estrogen during the interruption of treatment.

PATIENTS AND METHODS

SOLE enrolled 4884 postmenopausal women with hormone receptor-positive, lymph node-positive, operable breast cancer between December 2007 and October 2012 and among them, 104 patients were enrolled in SOLE-EST. They must have undergone local treatment and have completed 4-6 years of adjuvant ET. Patients were randomized between continuous letrozole (2.5 mg/day orally for 5 years) and intermittent letrozole treatment (2.5 mg/day for 9 months followed by a 3-month interruption in years 1-4 and then 2.5 mg/day during all of year 5).

RESULTS

Intention-to-treat population included 4851 women in SOLE (n = 2425 in the intermittent and n = 2426 in the continuous letrozole groups) and 103 women in SOLE-EST (n = 78 in the intermittent and n = 25 in the continuous letrozole groups). After a median follow-up of 84 months, 7-year disease-free survival (DFS) was 81.4% in the intermittent group and 81.5% in the continuous group (hazard ratio: 1.03, 95% confidence interval: 0.91-1.17). Reported adverse events were similar in both groups. Circulating estrogen recovery was demonstrated within 6 weeks after the stop of letrozole treatment.

CONCLUSIONS

Extended adjuvant ET by intermittent administration of letrozole did not improve DFS compared with continuous use, despite the recovery of circulating estrogen levels. The similar DFS coupled with previously reported quality-of-life advantages suggest intermittent extended treatment is a valid option for patients who require or prefer a treatment interruption.

Electrochemical degradation of per- and poly-fluoroalkyl substances using boron-doped diamond electrodes

Electrochemical degradation using boron-doped diamond (BDD) electrodes has been proven to be a promising technique for the treatment of water contaminated with per- and poly-fluoroalkyl substances (PFAS). Various studies have demonstrated that the extent of PFAS degradation is influenced by the composition of samples and electrochemical conditions. This study evaluated the significance of several factors, such as the current density, initial concentration of PFAS, concentration of electrolyte, treatment time, and their interactions on the degradation of PFAS. A 2⁴ factorial design was applied to determine the effects of the investigated factors on the degradation of perfluorooctanoic acid (PFOA) and generation of fluoride in spiked water. The best-performing conditions were then applied to the degradation of PFAS in wastewater samples. The results revealed that current density and time were the most important factors for PFOA degradation. In contrast, a high initial concentration of electrolyte had no significant impact on the degradation of PFOA, whereas it decreased the generation of F^-. The experimental design model indicated that the treatment of spiked water under a current density higher than 14 mA cm^-2 for 3-4 h could degrade PFOA with an efficiency of up to 100% and generate an F^- fraction of approximately 40-50%. The observed high PFOA degradation and a low concentration of PFAS degradation products indicated that the mineralization of PFOA was effective. Under the obtained best conditions, the degradation of PFOA in wastewater samples was 44-70%. The degradation efficiency for other PFAS in these samples was 65-80% for perfluorooctane sulfonic acid (PFOS) and 42-52% for 6-2 fluorotelomer sulfonate (6-2 FTSA). The presence of high total organic carbon (TOC) and chloride contents was found to be an important factor affecting the efficiency of PFAS electrochemical degradation in wastewater samples. The current study indicates that the tested method can effectively degrade PFAS in both water and wastewater and suggests that increasing the treatment time is needed to account for the presence of other oxidizable matrices.

Associations between trust and drinking among adolescents

INTRODUCTION

Trust is closely linked with health, but previous research on its association with alcohol use has yielded mixed findings. The aim of this study is to examine: (i) how two different dimensions of trust (general/institutional) are associated with alcohol use among adolescents; (ii) how these dimensions interact with alcohol use; and (iii) whether the associations are moderated by sex, parenting, health, school satisfaction or economic disadvantage.

METHODS

A nationwide sample of 5549 adolescents (aged 15-16 years) in Sweden answered a questionnaire in school. General and institutional trust were measured with five items each. Logistic regressions were used to examine associations between drinking and the trust dimensions, and the cross-combinations of these. Moderation by sex, parenting, health, school satisfaction and economic disadvantage was tested.

RESULTS

General and institutional trust were both significantly associated with drinking. High scores on both dimensions simultaneously were associated with the lowest probability of drinking, and low scores on both with the highest. Low institutional trust had a stronger association than low general trust. The combination of high institutional/low general trust was more protective than low institutional/high general trust. The association between general trust and drinking was moderated by school satisfaction, and the relationship between institutional trust and drinking was moderated by parental support and control.

DISCUSSION AND CONCLUSIONS

High trust is associated with a lower probability of past-year drinking among 15-16-year-olds. Parents and schools can be useful in endeavours to prevent low-trusting individuals in this age group from drinking.

How do former smokers perceive information about nicotine products? Evidence from Sweden

Purpose

Health promotion strategies often attempt to change people’s behavior through targeting their risk perceptions. These perceptions may, however, be moderated by other factors. This study therefore aimed at investigating the trustworthiness and consistency of risk information, as well as respondent perceptions of the adequacy of amount received among a representative sample of former smokers, and how this information is related to gender, age, education level and whether using nicotine or not.

Design/methodology/approach

The respondents are part of a seven-year follow-up of former smokers in Sweden. Initially, 1400 respondents were contacted, whereof 705 (response rate 50%) answered a Web-survey. The majority (85 %) was still nicotine-free but some made use of nicotine in different forms. The data analysis includes descriptive statistics and logistic regressions.

Findings

Most respondents trusted risk information whether offered by the public authorities or came from other sources such as media, and generally perceived that there was an adequate amount. However, there were some differences between the products, where quite a few distrusted information on Nicotine Replacement Therapies (NRTs) and some perceived the information on snus and NRTs as contradictory and too little.

Originality/value

Knowledge about how former smokers perceive information regarding negative aspects of cigarette use may facilitate more effective risk communication with current smokers, and it may also be important for communicating information about other nicotine products to those who are trying to or who already have quit smoking.

Myopathic changes in patients with long-term fatigue after COVID-19

Objective

To investigate the peripheral nerve and muscle function electrophysiologically in patients with persistent neuromuscular symptoms following Coronavirus disease 2019 (COVID-19).

Methods

Twenty consecutive patients from a Long-term COVID-19 Clinic referred to electrophysiological examination with the suspicion of mono- or polyneuropathy were included. Examinations were performed from 77 to 255 (median: 216) days after acute COVID-19. None of the patients had received treatment at the intensive care unit. Of these, 10 patients were not even hospitalized. Conventional nerve conduction studies (NCS) and quantitative electromyography (qEMG) findings from three muscles were compared with 20 age- and sex-matched healthy controls.

Results

qEMG showed myopathic changes in one or more muscles in 11 patients (55%). Motor unit potential duration was shorter in patients compared to healthy controls in biceps brachii (10.02 ± 0.28 vs 11.75 ± 0.21), vastus medialis (10.86 ± 0.37 vs 12.52 ± 0.19) and anterior tibial (11.76 ± 0.31 vs 13.26 ± 0.21) muscles. All patients with myopathic qEMG reported about physical fatigue and 8 patients about myalgia while 3 patients without myopathic changes complained about physical fatigue.

Conclusions

Long-term COVID-19 does not cause large fibre neuropathy, but myopathic changes are seen.

Significance

Myopathy may be an important cause of physical fatigue in long-term COVID-19 even in non-hospitalized patients.

Drinking motives and their associations with alcohol use among adolescents in Sweden

Aims:

Previous studies have shown a close association between drinking motives and drinking behaviour among adolescents. However, there is a lack of evidence from the Nordic countries since few studies covering this topic have been carried out in this context. The present study among Swedish adolescents aims to examine (1) the prevalence of different drinking motives, (2) how drinking motives are associated with drinking frequency and heavy drinking frequency, and (3) whether the associations are moderated by sex.

Methods:

A nationally representative sample ( n = 5,549) of Swedish adolescents (aged 15–16 years) answered a questionnaire in school. Of these, 2,076 were drinkers and were included in our study. Eighteen items from the Modified Drinking Motives Questionnaire-Revised (Modified DMQ-R) were used. Bivariate relationships between motives and drinking were examined with correlations. Linear regression models were used to assess the links between motives and drinking. Moderating effects of sex were examined with interactions.

Results:

Most common were social motives, followed by enhancement, coping-anxiety, coping-depression, and conformity motives. Coping-depression motives were slightly more common among girls. Conformity motives were associated with a lower frequency of drinking and heavy drinking while enhancement, social and coping-depression motives were associated with a higher frequency of both outcomes. No associations were found for coping-anxiety motives. No moderation effect of sex was found.

Conclusions:

Approach motives (social/enhancement) are the most prevalent drinking motives among Swedish adolescents. These also have the strongest association for both frequency of drinking and frequency of heavy drinking. This shows that Swedish adolescents drink to achieve something positive, rather than to avoid something negative, raising implications for prevention and intervention.

Similar countries, similar factors? Studying the decline of heavy episodic drinking in adolescents in Finland, Norway and Sweden

AIM

To (i) examine several factors associated with trends in heavy episodic drinking (HED) in Finland, Norway and Sweden, (ii) investigate similarities in these associations across the countries and (iii) analyse the contribution of these factors to the trend in HED and the differences across the countries.

DESIGN AND SETTING

Observational study using five waves of the European School Survey Project on Alcohol and Other Drugs (ESPAD) from Finland, Norway and Sweden between 1999 and 2015.

PARTICIPANTS

A total of 18 128 male and 19 121 female 15- to 16-year-old students.

MEASUREMENTS

Monthly HED, perceived access to alcohol, truancy, parental control, leisure time activities and daily smoking. The Cochran-Armitage test was used to examine linear time trends in HED. Logit regression models using the Karlson-Holm-Breen (KHB) method were fitted for each country separately, including all the independent variables together with time and adjusted for family status, parental education and gender.

FINDINGS

In Finland, Norway and Sweden, perceived access to alcohol, truancy and daily smoking decreased significantly between 1999 and 2015 whereas risk perceptions, parental control and participation in sports increased in the same period. The confounding percentage of all the independent variables related to the trend in HED was 48.8%, 68.9% and 36.7% for Finland, Norway and Sweden, respectively. Decline in daily smoking (P < 0.001) and perceived access to alcohol (P < 0.001) were positively and increase in parental control (P < 0.001) negatively associated with the decline in HED in all three countries. Changes in truancy, going out with friends, and engaging in sports and other hobbies had little or no impact on the decline in HED or displayed no consistent results across the countries.

CONCLUSIONS

The decline in adolescent heavy episodic drinking in Finland, Norway and Sweden between 1999 and 2015 appears to be associated with a decline in adolescent daily smoking and perceived access to alcohol and an increase in parental control.

Diagnosis and prevalence of diabetic polyneuropathy: a cross-sectional study of Danish patients with type 2 diabetes

BACKGROUND AND PURPOSE

Diabetic polyneuropathy (DPN) is a common complication of diabetes. Using the Toronto criteria for diabetic polyneuropathy and the grading system for neuropathic pain, the performance of neuropathy scales and questionnaires were assessed by comparing them to a clinical gold standard diagnosis of DPN and painful DPN in a cohort of patients with recently diagnosed type 2 diabetes.

METHODS

A questionnaire on neuropathy and pain was sent to a cohort of 5514 Danish type 2 diabetes patients. A sample of 389 patients underwent a detailed clinical examination and completed neuropathy questionnaires and scales.

RESULTS

Of the 389 patients with a median diabetes duration of 5.9 years, 126 had definite DPN (including 53 with painful DPN), 88 had probable DPN and 53 had possible DPN. There were 49 patients with other causes of polyneuropathy, neuropathy symptoms or pain, 10 with subclinical DPN and 63 without DPN. The sensitivity of the Michigan Neuropathy Screening Instrument questionnaire to detect DPN was 25.7% and the specificity 84.6%. The sensitivity of the Toronto Clinical Neuropathy Scoring System, including questionnaire and clinical examination, was 62.9% and the specificity was 74.6%.

CONCLUSIONS

Diabetic polyneuropathy affects approximately one in five Danish patients with recently diagnosed type 2 diabetes but neuropathic pain is not as common as previously reported. Neuropathy scales with clinical examination perform better compared with questionnaires alone, but better scales are needed for future epidemiological studies.

The CanMoRe trial - evaluating the effects of an exercise intervention after robotic-assisted radical cystectomy for urinary bladder cancer: the study protocol of a randomised controlled trial

Background

Patients who have undergone radical cystectomy for urinary bladder cancer are not sufficiently physically active and therefore may suffer complications leading to readmissions. A physical rehabilitation programme early postoperatively might prevent or at least alleviate these potential complications and improve physical function. The main aim of the CanMoRe trial is to evaluate the impact of a standardised and individually adapted exercise intervention in primary health care to improve physical function (primary outcome) and habitual physical activity, health-related quality of life, fatigue, psychological wellbeing and readmissions due to complications in patients undergoing robotic-assisted radical cystectomy for urinary bladder cancer.

Methods

In total, 120 patients will be included and assigned to either intervention or control arm of the study. All patients will receive preoperative information on the importance of early mobilisation and during the hospital stay they will follow a standard protocol for enhanced mobilisation. The intervention group will be given a referral to a physiotherapist in primary health care close to their home. Within the third week after discharge, the intervention group will begin 12 weeks of biweekly exercise. The exercise programme includes aerobic and strengthening exercises. The control group will receive oral and written information about a home-based exercise programme.

Physical function will serve as the primary outcome and will be measured using the Six-minute walk test. Secondary outcomes are gait speed, handgrip strength, leg strength, habitual physical activity, health-related quality of life, fatigue, psychological wellbeing and readmissions due to complications. The measurements will be conducted at discharge (i.e. baseline), post-intervention and 1 year after surgery. To evaluate the effects of the intervention mixed or linear regression models according to the intention to treat procedure will be used.

Discussion

This proposed randomised controlled trial has the potential to provide new knowledge within rehabilitation after radical cystectomy for urinary bladder cancer. The programme should be easy to apply to other patient groups undergoing abdominal surgery for cancer and has the potential to change the health care chain for these patients.

Trial registration

ClinicalTrials.gov. Clinical trial registration number NCT03998579. First posted June 26, 2019.

Are the well-off youth in Sweden more likely to use cannabis?

INTRODUCTION AND AIMS

Results from previous research are inconsistent regarding the association between socioeconomic status (SES) and cannabis use among adolescents. Since there are risks associated with cannabis use, a social gradient in cannabis use may contribute to reproducing socioeconomic differences in life opportunities. The aim of this study was to assess the association between childhood SES and cannabis use among youth in Sweden.

DESIGN AND METHODS

We used repeated cross-sectional data from three waves (2014-2016) of the Swedish national school survey among 11th graders. The analysis encompassed 9497 individuals in 668 school classes. Childhood SES was measured through parents' highest education, as reported by the students. Cannabis use was measured in terms of lifetime use and frequency of use. Data were analysed using multi-level mixed-effects Poisson regression.

RESULTS

Adolescents with at least 1 parent with university/college education had 17% (incidence rate ratio 1.17, confidence interval 1.05, 1.30) higher risk of lifetime use of cannabis compared with those whose parents had no university/college education, adjusting for sex, SES of the school environment, academic orientation, truancy, risk assessment and parental permissiveness. Among life-time users of cannabis, risk for frequent cannabis use was 28% (incidence rate ratio 0.72, confidence interval 0.53, 0.97) lower for those with at least 1 parent with university or college education.

DISCUSSION AND CONCLUSIONS

Childhood SES, in terms of parental education, was associated with cannabis use among Swedish adolescents. Adolescents from families with lower SES were less likely to ever try cannabis, but at higher risk for frequent use.

Social Inequalities in Harmful Drinking and Alcohol-Related Problems Among Swedish Adolescents

Aims

The study aims to examine how socio-economic status (SES) among youth is related to binge-drinking and alcohol-related problems using three SES indicators: (i) SES of origin (parental education level), (ii) SES of the school environment (average parental education level at student’s school) and (iii) SES of destination (academic orientation).

Methods

Cross-sectional data on upper secondary students (n= 4448) in Sweden. Multilevel logistic and negative binomial regression were used to estimate the relationship between each SES indicator and binge-drinking and alcohol-related problems, respectively.

Results

Only SES of destination was significantly associated with binge-drinking, with higher odds for students in vocational programmes (OR= 1.42, 95% CI= 1.13–1.80). For the second outcome, SES of destination (rr=1.25; 95%CI=1.08–1.45) and SES of the school environment (rr=1.19, 95% CI=1.02–1.39) indicated more alcohol-related problems in vocational programmes and in schools with lower-educated parents. After adjustment for drinking patterns, the relationship remained for SES of the school environment, but became non-significant for SES of destination.

Conclusion

Our results suggest that the SES gradient among youth is stronger for alcohol-related problems than for harmful drinking. By only focusing on SES differences in harmful alcohol use, researchers may underestimate the social inequalities in adverse alcohol-related outcomes among young people. Our findings also support the notion that the environment young people find themselves in matters for social inequalities in alcohol-related harm.

Abstract P5-12-01: A novel gene expression signature prognostic for both locoregional and distant failure and predictive for adjuvant radiotherapy

Background: Most patients with early stage breast cancer (BC) are treated with adjuvant radiotherapy (RT) following breast conserving surgery (BCS) to prevent locoregional recurrences (LRR). No predictive tools are currently available to select patients for RT, resulting in considerable over- and under treatment. We aimed to create and validate a gene expression-based classifier to prognosticate for LRR and to stratify patients for treatment with RT.

Patients and methods: A 27-gene expression signature was developed using three publicly available early stage BC gene expression datasets where patients were treated with RT and had detailed local recurrence information. The largest of the datasets was used to train the signature, and the other two datasets were used for signature refinement. As age was the strongest clinical factor for the endpoint in the training dataset, it was included in the model, resulting in a final clinical-genomic classifier of 27 genes and age. The classifier was locked before external validation in the SweBCG91-RT trial. This phase III clinical trial included primary tumors from 765 patients and for which gene expression data was available. The trial randomized node-negative BC patients to +/- RT following BCS, with sparse use of adjuvant systemic treatment (9%) and a median follow-up of 14.0 years for LRR in patients free from event. The classifier was validated using Cox regression with LRR as the primary endpoint, and hazard ratios (HRs) were calculated using the raw continuous classifier score (range: 0.5 to 2.5).

Results: The novel classifier was highly prognostic for LRR in SweBCG91-RT patients treated with RT (HR=7.5[3.3-16.9], p&lt;0.001), and remained prognostic in multivariate analysis (MVA) that included systemic treatment, subtype and grade (HR=7.2[3.1-16.4], p&lt;0.001). To a lesser extent, the classifier was also prognostic for LRR in patients not treated with RT (HR=1.9[1.0-3.5], p=0.03; MVA HR=1.9[1.0-3.3], p=0.05). Patients at high risk of LRR had a smaller effect of RT, and the treatment predictive potential was confirmed by testing for interaction (pinteraction=0.008). In patients treated with RT, age and the genomic component of the model were both prognostic for LRR (p&lt;0.01) as well as predictive for RT response (pinteraction&lt;0.05) and provided independent information (p&lt;0.01). The combined classifier has increased performance over its individual components (10-year AUC=0.72, 0.67, 0.65 for the classifier, age, and genomic component, respectively). While the novel signature was prognostic for metastasis (HR=4.3[2.3-7.8], p&lt;0.0001), calculated scores from previously published signatures to the metastasis endpoint, including the Oncotype-like score, were not prognostic for LRR.

Conclusions: This novel gene expression signature is highly prognostic for LRR, can identify patients at risk of LRR despite RT, and appears to be treatment predictive for adjuvant RT. Furthermore, the current signature is highly prognostic for metastasis. In contrast, calculated scores of previously published signatures modeled for the metastasis endpoint had inferior performance for LRR. These results underscore both the importance of signatures prognostic for LRR and the similarities in the biology of LRR and distant failure.

Citation Format: Sjöström M, Chang SL, Fishbane N, Davicioni E, Zhao SG, Hartman L, Holmberg E, Feng FY, Speers CW, Pierce LJ, Malmström P, Fernö M, Karlsson P. A novel gene expression signature prognostic for both locoregional and distant failure and predictive for adjuvant radiotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-01.

Abstract PD8-11: Distribution of locoregional breast cancer recurrences in relation to previous radiotherapy and biological subtype

Background: Adjuvant locoregional radiotherapy (LRRT) reduces risk of locoregional failures (LRF) and improves survival for node positive breast cancer (BC) patients. However, LRRT increases the risk for toxicity as edema in the arm, lung cancer and cardiac mortality. Modern radiotherapy allows a more conform therapy which makes knowledge of LRF-patterns very important, in order not to underdose volumes with high risk for microscopic disease and simultaneously restrict dose to risk organs. In addition, BC-subtype may affect radiosensitivity and could possibly be used to individualize LRRT in the future.

Methods: We investigated outcome for BC-patients receiving LRRT in the Southwest Sweden (2004-2008) in order to identify LRFs. During this period patients with &gt;3 positive lymph nodes were given LRRT (50Gy in 2Gy fractions) to the breast/thoracic wall, axilla level II+III, supra- and infraclavicular lymph nodes according to a target definition atlas introduced in 2002. Patients with LRF as first event were identified, with distant failures and death considered as competing risks. The anatomical distribution of LRF was compared with the contouring atlas, radiotherapy given, and biological subtype based on immunohistochemistry.

Results: 904 patients received LRRT. Median follow-up time was 9.8 years (0.2-14.6) for patients without an event. 59 patients (6,5%) developed a LRF, 30 of which were local failures (LF) and 31 regional failures (RF) (2 simultaneous LF/RF). Median time to LRF was 2.8 years. 37 of the 59 (63%) LRF-patients developed generalized disease within 3 months from the LRF. Of the 845 patients without LRF 316 developed distant metastases as first recurrence, 1 an isolated RF in the contralateral axilla, 64 died from other causes, and for 5 patients recurrence-status was unclear. 459 were alive at end of follow-up.

Of the LF 19 developed after mastectomy (MRM) and 11 after breast conserving surgery (BCS). LF-location after MRM: 9 in-field, 6 at field margin, 2 both in/out of field, 1 out of field, and for 1 not yet determined. After BCS: 8 in-field, 1 at field margin, and for 2 not yet determined. Of the RF 28 developed after MRM and 3 after BCS. Location of RF after MRM: 11 in-field, 6 at field margin, 1 both in/out of field, 2 out of field, and for 8 not yet determined. After BCS: 1 in-field, 1 at field margin, and 1 not yet determined. The most common location for RF close to /out of field was superior to the treated area in fossa supraclavicularis.

Biological approximate subtype was available for 885 of the primary tumours; luminal (ER+ and/or PR+ HER2-/?) 67% (589/885), HER2+ 19% (169/885), triple negative (ER- and PR- HER2-/?) (TN) 14% (127/885). Subtype distribution of BC later causing LRF despite LRRT was: luminal 44% (26/59), HER2+ 27% (16/59), TN 29% (17/59). Among primary tumours causing a LRF within irradiated volume 77% (24/31) were HER2+ or TN.

Conclusion: In this high risk cohort of BC-patients, we found a low incidence of LRFs. The majority of LRFs developed within irradiated volume. BCs of the HER2+ and TN-subtype may be more radioresistant and have a higher risk of LRF. Updated information as well as figures mapping all recurrences in relation to previous LRRT will be presented at the symposium.

Citation Format: Adra J, Karlsson P, Killander F, Lundstedt D, Alkner S. Distribution of locoregional breast cancer recurrences in relation to previous radiotherapy and biological subtype [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD8-11.

Abstract P2-06-19: The effect of UBE2C expression on intrinsic chemosensitivity in breast cancer cell lines

Background: The ubiquitin-proteasome pathway plays a crucial role in cancer-related processes by inducing cell cycle arrest through the degradation of mitotic cyclins and other cell cycle regulatory proteins. We recently showed that elevated levels of ubiquitin-conjugating enzyme E2C (UBE2C) were associated with aggressive tumor features and unfavorable clinical outcome in breast carcinoma (BC). UBE2C suppression has been achieved using the FDA-approved proteasome inhibitor bortezomib (VELCADE®) in colorectal carcinoma, but little is known about the efficacy of UBE2C-targeted therapy with proteasome inhibitors in breast cancer.

Methods: Cell viability assays were used to determine the intrinsic chemosensitivity of five BC cell lines (MCF-7, MDA-MB-436, HCC38, HCC1395, and ZR-75-30; stratified by UBE2C expression and ER status) and the MCF-10A epithelial cell line to proteasome inhibitors (n=8), mitosis inhibitors (n=2), and platinum agents (n=3). UBE2C expression analysis was performed using quantitative real-time PCR and Western blot. IC50 values and growth inhibition metrics (GR50 and GRmax) were calculated for each compound to determine drug potency and efficiency after 24 hour treatment. Proteasome activity was assessed using bortezomib-treated cells.

Results: Heterogeneous UBE2C expression levels were found in the different cell lines, with higher UBE2C levels in ER-negative BC cell lines (HCC38, HCC1395, MDA-MB-436) than ER-positive BC (MCF-7 and ZR-75-30) and MCF-10A control cells (ER-negative). Proteasome inhibition levels close to 50% and 100% were seen in all cell lines after 10 nM and 100 - 1000 nM bortezomib, respectively. As expected, bortezomib blocked cell cycle progression by inducing G2/M phase arrest in HCC38 cells. Due to differences in cell growth rates, calculation of the IC50 value was an ineffective method to determine drug potency. In contrast, the normalized growth rate inhibition method with GR50 and GRmax values demonstrated a correlation between sensitivity to proteasome inhibitors in ER-negative BC cell lines and high UBE2C expression levels. However, MDA-MB-436 cells (GR50, range 1.8-286.1 nM; GRmax, range -0.42- -0.93) were generally less sensitive to proteasome inhibitors than HCC38 cells (GR50, range 8.2-936.8 nM; GRmax, range -0.97- -0.99) though both cell lines were ER-negative, which was possibly due to the lower expression of UBE2C in MDA-MB-436 cells. Compared with the other tested drugs, no cell line was sensitive to the mitosis inhibitors and platinum agents were most effective in HCC38 cells.

Conclusions: Taken together, these findings suggest an association between UBE2C expression and response to proteasome inhibition, regardless of ER status.

Citation Format: Parris TZ, Larsson P, Biermann J, Engqvist H, Werner-Rönnerman E, Kovács A, Karlsson P, Helou K. The effect of UBE2C expression on intrinsic chemosensitivity in breast cancer cell lines [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-06-19.

Abstract P3-07-09: Tumour clonality in paired invasive breast carcinomas

Background: Multiple invasive breast tumours may represent either independent primary tumours or clonal recurrences of the first tumour, where the same progenitor cell gives rise to all of the detected tumours. Consequently, the driver events for the progenitor cell need to have been identical in early tumour development. Molecular classification of tumour clonality is not currently evaluated in multiple invasive breast carcinomas, despite evidence suggesting common clonal origins. Furthermore, there is no consensus about which type of biological data (e.g. copy number, mutation, histology) and especially which statistical method is most suitable to distinguish clonal recurrences from independent primary tumours.

Methods: Thirty-seven invasive breast tumour pairs were stratified by laterality (bilateral vs. ipsilateral) and the time interval between the diagnoses of the first and second tumours (synchronous vs. metachronous). Both tumours from the same patient were analysed by integrating clinical characteristics (n = 37), DNA copy number (n = 37), DNA methylation (n = 8), gene expression microarray (n = 7), RNA sequencing (n = 3), and SNP genotyping data (n = 3). Different statistical methods, e.g. the diagnostic similarity index (SI), distance measure, shared segment analysis etc., were used to classify the tumours from the same patient as clonally related recurrences or independent primary tumours.

Results: The SI applied on DNA copy numbers derived from aCGH (array comparative genomic hybridization) data was determined as the strongest indicator of clonal relatedness as it showed the highest concordance with all other methods. The distance measure was the most conservative method and the shared segment analysis most liberal. Concordant evidence for tumour clonality was found in 46% (17/37) of the patients. Notably, no significant association was found between the clinical characteristics and molecular tumour features.

Conclusions: A more accurate classification of clonal relatedness between multiple breast tumours may help to mitigate treatment failure and relapse by integrating tumour-associated molecular features, clinical parameters, and statistical methods. In cases of extremely similar or different tumour pairs, the results showed consistency regardless of the method used. The SI can be easily integrated into clinical routine using FFPE samples to obtain copy number data. However, clinical guidelines with exact thresholds need to be defined to standardize clonality testing in a routine diagnostic setting.

Citation Format: Biermann J, Parris TZ, Nemes S, Danielsson A, Engqvist H, Werner Rönnerman E, Forssell-Aronsson E, Kovács A, Karlsson P, Helou K. Tumour clonality in paired invasive breast carcinomas [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-07-09.

Has illicit drug use become normalised in groups of Swedish youth? A latent class analysis of school survey data from 2012 to 2015

Background:

It is often assumed that illicit drug use has become normalised in the Western world, as evidenced for example by increased prevalence rates and drug-liberal notions in both socially advantaged and disadvantaged youth populations. There is accumulating research on the characteristics of young illicit drug users from high-prevalence countries, but less is known about the users in countries where use is less common. There is reason to assume that drug users in low-prevalence countries may be more disadvantaged than their counterparts in high-prevalence countries, and that the normalisation thesis perhaps does not apply to the former context.

Aim:

This article aims to explore to what extent such assertions hold true by studying the characteristics of young illicit drug users in Sweden, where prevalence is low and drug policy centres on zero tolerance.

Material and Method:

We draw on a subsample (n = 3374) of lifetime users of illicit drugs from four waves of a nationally representative sample of students in 9th and 11th grade (2012–2015). Latent class analysis (LCA) on ten indicators pertaining to illicit drug use identified four classes which we termed “Marijuana testers”, “Marijuana users”, “Cannabinoid users” and “Polydrug users”.

Findings:

Indications of social advantage/disadvantage such as peer drug use, early substance-use debut and truancy varied across groups, particularly between “Marijuana testers” (low scores) and “Polydrug users” (high scores).

Conclusions:

Our findings corroborate the idea that the majority of those who have used illicit drugs in the Swedish youth population have tried marijuana a few times only. We discuss whether or not the comparably large share of socially advantaged “Marijuana testers” in a comparably small sample of lifetime users can be interpreted as a sort of normalisation in a prohibitionist drug policy context.

Ethyl carbamate in Swedish and American smokeless tobacco products and some factors affecting its concentration

BACKGROUND

We are interested in comparing the levels of harmful or potentially harmful constituents in Swedish and American smokeless tobacco products (STPs). We report here the concentrations of the IARC Group 2 A (probable human) carcinogen ethyl carbamate (EC) in seventy commercial STPs from the US and Sweden, representing 80-90% of the market share of the major STP categories in these countries. We also examine the effects of various additives, processing and storage conditions on EC concentrations in experimental snus samples.

RESULTS

EC was determined from aqueous extracts of the STPs using ultra performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS). EC was undetectable (< 20 ng/g wet weight basis WWB) in 60% of the commercial STPs, including all the chewing tobacco (CT), dry snuff (DS), hard pellet (HP), soft pellet (SP), and plug products. Measurable levels of EC were found in 11/16 (69%) of the moist snuff (MS) samples (average 154 ng/g in those samples containing EC) and 19/32 (59%) of the Swedish snus samples (average 35 ng/g). For the experimental snus samples, EC was only observed in ethanol treated samples. EC concentrations increased significantly with ethanol concentrations (0-4%) and with storage time (up to 24 weeks) and temperature (8 °C vs 20 °C). EC concentrations were lower at lower pHs but were unaffected by adding nitrogenous precursors identified from food studies (citrulline and urea), increasing water content or by pasteurisation. Added EC was stable in the STP matrix, but evaporative losses were significant when samples were stored for several weeks in open containers at 8 °C.

CONCLUSIONS

EC was found in measurable amounts only in some moist STPs i.e. pasteurised Swedish snus and unpasteurised US MS; it is not a ubiquitous contaminant of STPs. The presence of ethanol contributed significantly to the presence of EC in experimental snus samples, more significantly at higher pH levels. Sample age also was a key determinant of EC content. In contrast, pasteurisation and fermentation do not appear to directly influence EC levels. Using published consumption rates and mouth level exposures, on average STP consumers are exposed to lower EC levels from STP use than from food consumption.

A pain in the skin. Regenerating nerve sprouts are distinctly associated with ongoing burning pain in patients with diabetes

BACKGROUNDS

Patients with diabetic polyneuropathy commonly suffer from ongoing burning pain and dynamic mechanical allodynia. In this clinical and skin biopsy study, we aimed at assessing how intraepidermal regenerating nerve sprouts are associated with these two types of pain.

METHODS

We consecutively enrolled 85 patients with diabetic polyneuropathy. All patients underwent skin biopsy at the distal leg. Intraepidermal nerve fibres were immunostained with the anti-protein gene product 9.5 (PGP9.5) to quantify all intraepidermal nerve fibres, and the growth-associated protein 43 (GAP43) to quantify regenerating nerve sprouts.

RESULTS

We found that the GAP43-stained intraepidermal nerve fibre density and the ratio GAP43/PGP9.5 were significantly higher in patients with ongoing burning pain than in those without. The area of receiver operating characteristic (ROC) curve for the ratio GAP43/PGP9.5 was 0.74 and yielded a sensitivity and specificity for identifying ongoing burning pain of 72% and 71%, respectively. Conversely, although the density of PGP9.5 and GAP43 intraepidermal nerve fibre was higher in patients with dynamic mechanical allodynia than in those without, this difference was statistically weak and the ROC curve analysis of skin biopsy variables for this type of pain failed to reach the statistical significance.

CONCLUSION

Our clinical and skin biopsy study showed that ongoing burning pain was strongly associated with regenerating sprouts, as assessed with GAP43 immunostaining. This finding improves our understanding on the mechanisms underlying neuropathic pain in patients with diabetic polyneuropathy and suggests that the GAP43/PGP 9.5 ratio might be used as an objective marker for ongoing burning pain due to regenerating sprouts.

SIGNIFICANCE

Our skin biopsy study showing that regenerating sprouts, as assessed with GAP43-staining, were strongly associated with ongoing burning pain, improves our knowledge on the mechanisms underlying neuropathic pain in patients with diabetes.

Individual and school-class correlates of youth cannabis use in Sweden: A multilevel study

Background and aims:

The school-class context is a crucial social environment for young people but substance use researchers have largely overlooked potential influences operating at this level. This study explores associations between school-class and individual-level factors and cannabis use in Swedish youth.

Data and methods:

Data comprised four waves (2012–2015) of the Swedish Council for Information on Alcohol and Other Drugs’ (CAN) nationally representative school surveys among individuals in 9th and 11th grade. For the present analyses, we had data on totally 28,729 individuals from 2377 unique school classes. Multilevel logistic regressions predicted lifetime and 10+ times use of cannabis from both individual-level predictors and school-class-level measures derived from the individual-level variables.

Results:

There were individual-level associations between most predictor variables and cannabis use. An early debut of tobacco use and binge drinking as well as low cannabis related risk perceptions had strong associations with cannabis use. Conversely, several school-class-level variables had aggregate relationships with cannabis use, most notably the overall level of risk perceptions in the school class. Some of the school-class factors predicted cannabis use over and above the individual-level covariates, suggesting the presence of contextual effects. Surprisingly, while female gender was negatively related with cannabis use at the individual level, a higher proportion of females in the classroom increased the odds for lifetime cannabis use even after controlling for individual and other contextual-level covariates.

Conclusions:

Youth cannabis use is related to various factors at both the individual and school-class level in Sweden. Truancy and perceived risk related to cannabis use had contextual associations with cannabis use. The positive contextual association between a higher proportion of females in the classroom and lifetime use should be explored further.