Lack of consistency in measurement methods and semantics used for network measures in adolescent health behaviour studies using social network analysis: a systematic review.

BACKGROUND: Social network analysis (SNA) is often used to examine how social relationships influence adolescent health behaviours, but no study has documented the range of network measures used to do so. We aimed to identify network measures used in studies on adolescent health behaviours. METHODS: We conducted a systematic review to identify network measures in studies investigating adolescent health behaviours with SNA. Measures were grouped into eight categories based on network concepts commonly described in the literature: popularity, position within the network, network density, similarity, nature of relationships, peer behaviours, social norms, and selection and influence mechanisms. Different subcategories were further identified. We detailed all distinct measures and the labels used to name them in included articles. RESULTS: Out of 6686 articles screened, 201 were included. The categories most frequently investigated were peer behaviours (n=201, 100%), position within the network (n=144, 71.6%) and popularity (n=110, 54.7%). The number of measurement methods varied from 1 for 'similarity on popularity' (within the 'similarity' category) to 28 for the 'characterisation of the relationship between the respondent and nominated peers' (within the 'nature of the relationships' category). Using the examples of 'social isolation', 'group membership', 'individuals in a central position' (within the 'position within the network' category) and 'nominations of influential peers' (sub within the 'popularity' category), we illustrated the inconsistent reporting and heterogeneity in measurement methods and semantics. CONCLUSION: Robust methodological recommendations are needed to harmonise network measures in order to facilitate comparison across studies and optimise public health intervention based on SNA.

A Systematic Review of Qualitative Studies on Factors Associated With Smoking Cessation Among Adolescents and Young Adults.

OBJECTIVE: To summarize findings from qualitative studies on factors associated with smoking cessation among adolescents and young adults. DATA SOURCES: We searched Pubmed, Psychinfo, CINAHL, Embase, Web of Science, and SCOPUS databases, as well as reference lists, for peer-reviewed articles published in English or French between January 1, 2000, and November 18, 2020. We used keywords such as adolescents, determinants, cessation, smoking, and qualitative methods. STUDY SELECTION: Of 1724 records identified, we included 39 articles that used qualitative or mixed methods, targeted adolescents and young adults aged 10-24, and aimed to identify factors associated with smoking cessation or smoking reduction. DATA EXTRACTION: Two authors independently extracted the data using a standardized form. We assessed study quality using the National Institute for Health and Care Excellence checklist for qualitative studies. DATA SYNTHESIS: We used an aggregative meta-synthesis approach and identified 39 conceptually distinct factors associated with smoking cessation. We grouped them into two categories: (1) environmental factors [tobacco control policies, pro-smoking norms, smoking cessation services and interventions, influence of friends and family], and (2) individual attributes (psychological characteristics, attitudes, pre-quitting smoking behavior, nicotine dependence symptoms, and other substances use). We developed a synthetic framework that captured the factors identified, the links that connect them, and their associations with smoking cessation. CONCLUSIONS: This qualitative synthesis offers new insights on factors related to smoking cessation services, interventions, and attitudes about cessation (embarrassment when using cessation services) not reported in quantitative reviews, supplementing limited evidence for developing cessation programs for young persons who smoke. IMPLICATIONS: Using an aggregative meta-synthesis approach, this study identified 39 conceptually distinct factors grouped into two categories: Environmental factors and individual attributes. These findings highlight the importance of considering both environmental and individual factors when developing smoking cessation programs for young persons who smoke. The study also sheds light on self-conscious emotions towards cessation, such as embarrassment when using cessation services, which are often overlooked in quantitative reviews. Overall, this study has important implications for developing effective smoking cessation interventions and policies that address the complex factors influencing smoking behavior among young persons.

Social network analysis to study health behaviours in adolescents: A systematic review of methods.

PURPOSE: Our objectives were (i) to systematically review how SNA is used in studies investigating adolescent health behaviours (i.e., the purpose of using SNA, methods used for network data collection and analysis), and (ii) to develop methodological guidelines to help researchers use SNA in studies on adolescent health behaviours. METHODS: Five databases were searched using keywords related to "social network analysis" and "adolescents". We extracted data from included articles pertaining to the choice of methods for network data collection and analysis. We used these data to develop a 5-step decision tree to help researchers make methodological decisions most appropriate to their research objectives. RESULTS: A total of 201 articles were included. Most investigated tobacco (50%) or alcohol use (48%). SNA was used most often to examine processes related to peer selection or influence (37%) and/or to examine the effect of sociometric position on health behaviours (34%). 181 studies (90%) used a sociocentric approach for SNA, 16 studies (8%) used an egocentric approach, and 4 studies (2%) used both. We identified five decision-making steps in SNA including the choice of: (i) network boundary, (ii) SNA approach, (iii) methods for name generators, (iv) methods for name interpreters, and (iv) SNA indicators. CONCLUSION: This study provides insights and guidance in a 5-step decision tree on practical and methodological considerations in using SNA to explore adolescent health behaviours.

Impact of referral bias on prognostic studies outcomes: insights from a population-based cohort study on infective endocarditis.

PURPOSE: Prognostic studies derived from samples of patients managed in tertiary hospitals are subject to referral bias. We aimed to characterize this bias using the example of infective endocarditis. METHODS: We analyzed data from a French population-based cohort, which included 497 patients with infective endocarditis. Patients were admitted directly to a tertiary hospital (Group T), admitted to a non-tertiary hospital and referred to a tertiary hospital (Group NTT) or not (Group NT). We compared patients' characteristics, survival rates and prognostic factors between groups. RESULTS: Compared with Group T (n = 291), NTT patients (n = 144) were more often males (81.3% vs. 72.5%; P = .046), injection drug users (9.7% vs. 4.5%; P = .033), and had more frequent surgical indications (78.5% vs. 64.3%; P = .003). Compared with Group NT (n = 62), NTT patients were more often males (81.3% vs. 67.7%; P = .034) and had surgical indications more often (78.5% vs. 19.4%; P < .001). One-year survival was higher in NTT + T patients than in NT patients (73.0% vs. 56.1%; P = .01). Prognostic factors and hazard ratios estimates varied across groups. CONCLUSIONS: When derived from samples mixing patients admitted directly and those referred to tertiary hospitals, validity of characteristics description, survival estimates, and hazard ratios is threatened by referral bias.

Data on prognostic factors associated with 3-month and 1-year mortality from infective endocarditis.

This article describes supplementary tables and figures associated with the research paper entitled "Impact of referral bias on prognostic studies outcomes: insights from a population-based cohort study on infective endocarditis". The aforementioned paper is a secondary analysis of data from the EI 2008 cohort on infective endocarditis and aimed at characterising referral bias. A total of 497 patients diagnosed with definite infective endocarditis between January 1st and December 31st 2008 were included in EI 2008. Data were collected from hospital medical records by trained clinical research assistants. Patients were divided into three groups: admitted to a tertiary hospital (group T), admitted to a non-tertiary hospital and referred secondarily to a tertiary hospital (group NTT) or admitted to a non-tertiary hospital and not referred (group NT). The pooled (NTT+T) group mimicked studies recruiting patients in tertiary hospitals only. Two different starting points were considered for follow up: date of first hospital admission and date of first admission to a tertiary hospital if any (hereinafter referred to as "referral time"). Referral bias is a type of selection bias which can occur due to recruitment of patients in tertiary hospitals only (excluding those who are admitted to non-tertiary hospitals and not referred to tertiary hospitals). This bias may impact the description of patients' characteristics, survival estimates as well as prognostic factors identification. The six tables presented in this paper illustrate how patients' selection (population-based sample [pooled (NT+NTT+T) group] versus recruitment in tertiary hospitals only [pooled (NTT+T) group]) might impact Hazards Ratios values for prognostic factors. Crude and adjusted Cox regression analyses were first performed to identify prognostic factors associated with 3-month and 1-year mortality in the whole sample using inclusion as the starting point. Analyses were then performed in the pooled (NTT+T) group first using inclusion as the starting point and finally using referral time as the starting point. Figures 1 to 3 illustrate how HR increase with time for covariates that were considered as time-varying covariates (covariate*time interaction).