Motivational interviewing as a way to promote physical activity in obese adolescents: A randomised-controlled trial using self-determination theory as an explanatory framework

International audienceUsing self-determination theory (SDT) as an explanatory framework, this randomised-controlled study evaluates the effect of a motivational interviewing (MI)-based intervention as an addition to a standard weight loss programme (SWLP) on physical activity (PA) practice in obese adolescents over a six-month period. Fifty-four obese adolescents (mean age = 13 years, mean BMI = 29.57 kg/m²) were randomly assigned to an SWLP group (n = 28) or SWLP + MI group (n = 26). Both groups received two SWLP sessions, supplemented for the SWLP + MI group, by six MI sessions. Perceived autonomy support, perceived competence, motivational regulations, PA and BMI were assessed at baseline, three and six months (i.e. the end of the programme). MLM analyses revealed that compared to SWLP, the SWLP + MI group had a greater BMI decrease and a greater PA practice increase over time. Moreover, the SWLP + MI group reported greater autonomy support from medical staff at the end of the programme, greater increase in integrated and identified regulations and a stronger decrease in amotivation. MI appears as an efficient counselling method as an addition to an SWLP to promote PA in the context of pediatric obesity

Motivation des adolescents obèses pour l'activité physique. Les apports de la théorie de l'autodétermination et de l'entretien motivationnel

L'obésité représente à l'heure actuelle un problème de santé publique majeur. Malgré le rôle essentiel de l'activité physique (AP) dans la gestion du poids, de nombreuses études rapportent les difficultés d'engagement des populations obèses dans un style de vie actif. Ce travail doctoral porte sur l'étude des déterminants psychosociaux de l'AP des personnes obèses. Une méta-analyse a tout d'abord été conduite afin de déterminer l'impact des interventions faisant la promotion de l'AP auprès des populations obèses. L'analyse des 49 études publiées à ce jour, a permis de conclure à un impact significatif, mais modéré (d = 0.44) des interventions, sur l'AP des participants. Si quelques variables (e.g., durée, type d'indicateurs d'AP, format des sessions) semblent moduler le poids des interventions, il n'a pas été possible de tirer des conclusions concernant les processus psychosociaux impliqués dans ces effets. Prenant appui sur la théorie de l'autodétermination (TAD, Deci & Ryan, 2002), un programme de recherche constitué de 3 études complémentaires a ensuite été réalisé, afin (1) d'améliorer la compréhension des mécanismes motivationnels associés à l'adoption d'AP chez des adolescents obèses, et (2) d'évaluer l'impact d'une intervention motivationnelle destinée à rendre cette population plus active physiquement. Suivant un plan corrélationnel transversal, l'étude 1 avait pour objectif d'identifier les patterns motivationnels spécifiquement associés à différents types d'AP (i.e., AP sportive, de loisir, domestique). Les résultats suggèrent que l'AP de loisir est associée à un niveau élevé de régulations identifiée et intégrée, et à un faible niveau d'introjection. La pratique sportive est quant à elle, associée à un niveau élevé d'introjection et un faible niveau de régulation externe. L'étude 2 a exploré, par l'intermédiaire d'une méthodologie qualitative, les facteurs motivationnels associés au succès ou à l'échec d'un programme de gestion du poids pour adolescents. Les résultats indiquent que les participants ayant réussi à perdre du poids semblaient bénéficier d'un plus grand soutien de la part de la famille, et manifestaient une plus grande motivation autodéterminée à maintenir leurs comportements de santé. Enfin, à partir d'un plan randomisé contrôlé sur 6 mois, l'étude 3 a cherché à déterminer si l'ajout de 6 entretiens motivationnels (EM, Miller & Rollnick, 2002) augmentait l'efficacité d'un programme cognitivo-comportemental de gestion du poids. Comparés aux participants n'ayant bénéficié que du programme de gestion du poids, les analyses multi-niveaux montrent que les adolescents qui ont bénéficié à la fois des EM et du programme de gestion du poids présentaient (1) une plus grande augmentation de leur AP (auto-rapportée et objective), (2) une plus grande hausse des régulations identifiée et intégrée, (3) un niveau supérieur de soutien de l'autonomie du personnel médical, et (4) une diminution plus importante du niveau d'amotivation. Pris dans leur ensemble, ces résultats soulignent à la fois l'intérêt de l'EM, comme une stratégie pertinente pour promouvoir l'AP des adolescents obèses, et celui de la TAD comme cadre explicatif des mécanismes motivationnels associés à l'adoption d'AP chez des adolescents obèses.Obesity currently represents a major public health issue. Despite the fact that physical activity (PA) is recognized to play a key role in weight control, numerous studies tend to show that obese populations experience difficulties in the adoption of an active lifestyle. This doctoral dissertation deals with the psychosocial determinants of PA among obese populations. A meta-analysis was first conducted so as to determine the impact of interventions promoting PA among obese populations. Inclusion of 49 studies published to date enabled to conclude to the existence of a significant, but moderated (d=0.44), impact of interventions on participants' PA. Despite the fact that few variables (e.g., duration, type of PA indicator, format of sessions) modulated impact of interventions, few results appeared concerning the psychosocial processes implicated in those effects. Based on self-determination theory (SDT, Deci & Ryan, 2002), a program of research comprising 3 complementary studies was then conducted in order to (1) enhance the understanding of the motivational mechanisms associated with a PA adoption among obese adolescents, and (2) evaluate the impact of a motivational intervention aiming at helping this population to become more physically active. Using a cross-sectional methodology, study 1 aimed at indentifying the motivational patterns specifically associated with different type of PA (i.e., leisure time PA, sport, daily PA). The results suggest that leisure time PA is associated with high levels of identified and integrated regulations, as well as low levels of introjection. Sport participation was associated with high levels of introjection and low levels of external regulation. Study 2 explored with a qualitative methodology the motivational factors associated with the success or failure of a weight loss program for adolescents. The results indicate that participants who succeeded in losing weight expressed more support from their family and more autonomous reasons to maintain health behaviors. Lastly, study 3 consisted in a randomized controlled trial of 6 months aimed at determining to what extent the addition 6 motivational interviewing sessions (MI, Miller & Rollnick, 2002) would impact the efficacy of a cognitive-behavioral weight loss program. Compared to participants who only benefited from the weight loss program, multilevel analyses reveal that adolescents who received both MI and weight loss program reported (1) an higher increase of PA (self-reported and objective), (2) an higher increase of integrated and identified regulations, (3) an higher autonomy support from medical staff and (4) a more important decrease of amotivation. Taken globally, those results both suggest interest of MI as a pertinent counseling method to promote PA among obese adolescent population as well as interest of SDT as an explanatory framework of motivational processes associated with PA adoption among obese adolescents.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Reactivity of neodymium carriers in deep sea sediments: Implications for boundary exchange and paleoceanography

The dissolved neodymium (Nd) isotopic distribution in the deep oceans is determined by continental weathering inputs, water mass advection, and boundary exchange between particulate and dissolved fractions. Reconstructions of past Nd isotopic variability may therefore provide evidence on temporal changes in continental weathering inputs and/or ocean circulation patterns over a range of timescales. However, such an approach is limited by uncertainty in the mechanisms and importance of the boundary exchange process, and the challenge in reliably recovering past seawater Nd isotopic composition (εNd) from deep sea sediments. This study addresses these questions by investigating the processes involved in particulate–solution interactions and their impact on Nd isotopes. A better understanding of boundary exchange also has wider implications for the oceanic cycling and budgets of other particle-reactive elements. Sequential acid-reductive leaching experiments at pH ∼2–5 on deep sea sediments from the western Indian Ocean enable us to investigate natural boundary exchange processes over a timescale appropriate to laboratory experiments. We provide evidence that both the dissolution of solid phases and exchange processes influence the εNd of leachates, which suggests that both processes may contribute to boundary exchange. We use major element and rare earth element (REE) data to investigate the pools of Nd that are accessed and demonstrate that sediment leachate εNd values cannot always be explained by admixture between an authigenic component and the bulk detrital component. For example, in core WIND 24B, acid-reductive leaching generates εNd values between −11 and −6 as a function of solution/solid ratios and leaching times, whereas the authigenic components have εNd ≈ −11 and the bulk detrital component has εNd ≈ −15. We infer that leaching in the Mascarene Basin accesses authigenic components and a minor radiogenic volcanic component that is more reactive than Madagascan-derived clays. The preferential mobilisation of such a minor component demonstrates that the Nd released by boundary exchange could often have a significantly different εNd composition than the bulk detrital sediment. These experiments further demonstrate certain limitations on the use of acid-reductive leaching to extract the εNd composition of the authigenic fraction of bulk deep sea sediments. For example, the detrital component may contain a reactive fraction which is also acid-extractible, while the incongruent nature of this dissolution suggests that it is often inappropriate to use the bulk detrital sediment elemental chemistry and/or εNd composition when assessing possible detrital contamination of leachates. Based on the highly systematic controls observed, and evidence from REE patterns on the phases extracted, we suggest two approaches that lead to the most reliable extraction of the authigenic εNd component and good agreement with foraminiferal-based approaches; either (i) leaching of sediments without a prior decarbonation step, or (ii) the use of short leaching times and low solution/solid ratios throughout

Matched or nonmatched interventions based on the transtheoretical model to promote physical activity. A meta-analysis of randomized controlled trials

The aim of this study was to examine whether the efficacy of transtheoretical model (TTM)–based interventions on physical activity (PA) varied according to the following criteria: (1) interventions targeted the actual stages of change (SOCs) or did not; (2) participants were selected according to their SOC or were not; and (3) its theoretical constructs (decisional balance, temptation, self-efficacy, processes of change). Thirty-three randomized controlled trials assessing TTM-based interventions promoting PA in adults were systematically identified. The between-group heterogeneity statistic (Qb) did not reveal any differential efficacy either in interventions targeting the actual SOC compared with those that did not (Qb = 1.28, p = 0.22) or in interventions selecting participants according to their SOC compared with those that did not (Qb = 0.01, p = 0.91). TTM-based interventions enhanced PA behavior whether they targeted the actual SOC (Cohen's d = 0.36; 95% confidence interval (CI): 0.22–0.49)) or not (d = 0.23; 95% CI: 0.09–0.38) and whether they selected their participants according to their SOC (d = 0.33; 95% CI: 0.13–0.53) or not (d = 0.32; 95% CI: 0.19–0.44). The moderators of the efficacy of TTM-based interventions were the number of theoretical constructs used to tailor the intervention (Qb = 8.82, p = 0.003), the use of self-efficacy (Qb =6.09, p = 0.01), and the processes of change (Qb = 3.51, p = 0.06). TTM-based interventions significantly improved PA behavior, and their efficacy was not moderated by SOC but by the TTM theoretical constructs

Changes in Indian Summer Monsoon Using Neodymium (Nd) Isotopes in the Andaman Sea During the Last 24,000 years

Dramatic changes from a cold and dry last glacial to a warm and wet Holocene period intensified the Indian summer monsoon (ISM), resulting in vigorous hydrology and increased terrestrial erosion. Here we present seawater neodymium (Nd) data (expressed in εNd) from Andaman Sea sediments to assess past changes in the ISM and the related impact of Irrawaddy–Salween and Sittoung (ISS) river discharge into the Andaman Sea in the northeastern Indian Ocean. Four major isotopic changes were identified: (1) a gradual increase in εNd toward a more radiogenic signature during the Last Glacial Maximum (22–18 ka), suggesting a gradual decrease in the ISS discharge; (2) a relatively stable radiogenic seawater εNd between 17.2 and 8.8 ka, perhaps related to a stable reduced outflow; (3) a rapid transition to less radiogenic εNd signature after 8.8 ka, reflecting a very wet early–mid-Holocene with the highest discharge; and (4) a decrease in εNd signal stability in the mid–late Holocene. Taking into account the contribution of the ISS rivers to the Andaman Sea εNd signature that changes proportionally with the strengthening (less radiogenic εNd) or weakening (more radiogenic εNd) of the ISM, we propose a binary model mixing between the Salween and Irrawaddy rivers to explain the εNd variability in Andaman Sea sediments. We hypothesize that the Irrawaddy river mainly contributed detrital sediment to the northeastern Andaman Sea for the past 24 ka. Our εNd data shed new light on the regional changes in Indo-Asian monsoon systems when compared with the existing Indian and Chinese paleo-proxy records

Selenium nanoparticles trigger alterations in ovarian cancer cell biomechanics

High dose selenium acts as a cytotoxic agent, with potential applications in cancer treatment. However, clinical trials have failed to show any chemotherapeutic value of selenium at safe and tolerated doses (<90 μg/day). To enable the successful exploitation of selenium for cancer treatment, we evaluated inorganic selenium nanoparticles (SeNP), and found them effective in inhibiting ovarian cancer cell growth. In both SKOV-3 and OVCAR-3 ovarian cancer cell types SeNP treatment resulted in significant cytotoxicity. The two cell types displayed contrasting nanomechanical responses to SeNPs, with decreased surface roughness and membrane stiffness, characteristics of OVCAR-3 cell death. In SKOV-3, cell membrane surface roughness and stiffness increased, both properties associated with decreased metastatic potential. The beneficial effects of SeNPs on ovarian cancer cell death appear cell type dependent, and due to their low in vivo toxicity offer an exciting opportunity for future cancer treatment

Donald J. Jamison Sr. v. Utah Home Fire Insurance Company : Brief of Respondent

Appeal from the Judgment of the Third Judicial District Court, Salt Lake County- Honorable Stewart M. Hanson, Jr

Differing impact of the COVID-19 pandemic on youth mental health: combined population and clinical study

Background: Identifying youths most at risk to COVID-19-related mental illness is essential for the development of effective targeted interventions. Aims: To compare trajectories of mental health throughout the pandemic in youth with and without prior mental illness and identify those most at risk of COVID-19-related mental illness. Method: Data were collected from individuals aged 18-26 years (N = 669) from two existing cohorts: IMAGEN, a population-based cohort; and ESTRA/STRATIFY, clinical cohorts of individuals with preexisting diagnoses of mental disorders. Repeated COVID-19 surveys and standardised mental health assessments were used to compare trajectories of mental health symptoms from before the pandemic through to the second lockdown. Results: Mental health trajectories differed significantly between cohorts. In the population cohort, depression and eating disorder symptoms increased by 33.9% (95% CI 31.78-36.57) and 15.6% (95% CI 15.39-15.68) during the pandemic, respectively. By contrast, these remained high over time in the clinical cohort. Conversely, trajectories of alcohol misuse were similar in both cohorts, decreasing continuously (a 15.2% decrease) during the pandemic. Pre-pandemic symptom severity predicted the observed mental health trajectories in the population cohort. Surprisingly, being relatively healthy predicted increases in depression and eating disorder symptoms and in body mass index. By contrast, those initially at higher risk for depression or eating disorders reported a lasting decrease. Conclusions: Healthier young people may be at greater risk of developing depressive or eating disorder symptoms during the COVID-19 pandemic. Targeted mental health interventions considering prior diagnostic risk may be warranted to help young people cope with the challenges of psychosocial stress and reduce the associated healthcare burden

Developing self-regulation for dietary temptations: intervention effects on physical, self-regulatory and psychological outcomes

We aimed to investigate whether a self-regulatory skills intervention can improve weight loss-related outcomes. Fifty-five participants (M BMI = 32.60 ± 4.86) were randomized into self-regulation training and advice groups and received two training workshops and weekly practice tasks. The self-regulation training group was trained to use six self-regulatory skills: Delayed gratification, thought control, goal setting, self-monitoring, mindfulness, and coping. The advice group received dietary and physical activity advice for weight loss. Physical, self-regulatory, and psychological measures were taken at baseline, end of intervention (week 8) and at follow-up (week 12). Using intention-to-treat analysis, weight, waist circumference, body fat and body mass index (BMI) were significantly reduced at follow-up for both groups. There were significant increases in all six self-regulatory skills and the psychological measures of self-efficacy, self-regulatory success, and physical self-worth for both groups. Results indicate that self-regulatory skills training might be as effective as dietary and physical activity advice in terms of weight loss and related outcomes