Personality, stress and risk of Parkinson's disease

The objective of this thesis was to investigate the relationship of personality and stress with subsequent risk of Parkinson’s disease (PD). In Study I, we conducted a population-based cohort study using questionnaire data from the Swedish Twin Registry to explore whether the personality traits, neuroticism and introversion, were associated with later PD risk. We also explored the role of smoking as a mediator in the relationship between personality and PD. Both neuroticism and introversion were associated with an increased PD risk. Further, smoking was a significant mediator in the relationship between personality traits and PD that partly accounted for the effect of introversion, whereas it acted as a suppressor for the effect of neuroticism on PD risk. In Study II, we wanted to further explore the main findings from study I, with the aim to examine whether the observed associations between neuroticism, smoking and PD may be causal. We conducted a two-sample Mendelian randomization study in a network framework, consisting of three main analyses: (I) causal effect of neuroticism on PD, (II) causal effect of neuroticism on smoking initiation, (III) causal effect of smoking initiation on PD. We found no support for a causal association between neuroticism and PD risk. On the other hand, the results indicated that the association between neuroticism and smoking initiation is causal and that there is a strong causal effect of smoking initiation on a reduced PD risk. In Study III, we explored the association between occupational stress according to the job demands-control model and risk of PD. We conducted a population-based cohort study including individuals born in Sweden between 1920 and 1950 who had an occupation in 1980 or 1970. Levels of job demands and control were determined using a job-exposure matrix. High job demands was associated with increased PD risk in men, especially in men with high education, whereas high job control was associated with increased PD risk among low educated, more strongly in women. High-strain jobs (high demands and low control) were only associated with increased PD risk among men with high education, whereas active jobs (high demands and high control) were associated with increased PD risk among men with low education. In Study IV, we conducted a population- and sibling-matched cohort study to investigate the association between stress-related disorders and neurodegenerative diseases. Stress-related disorders (i.e. post-traumatic stress disorder (PTSD), acute stress reaction, adjustment disorder, and other stress reactions) and neurodegenerative diseases (classified as primary and vascular neurodegenerative diseases, as well as Alzheimer’s disease (AD), PD, and amyotrophic lateral sclerosis (ALS)) were identified through the national patient register. We found that stress-related disorders were associated with increased risk of neurodegenerative diseases in general. The association was stronger for vascular neurodegenerative diseases, which might indicate importance of a cerebrovascular pathway. A statistically significant association was found for AD alone, but not for PD or ALS, although the estimates pointed in the same direction

Modalités de recrutement des sujets dans la recherche en pédiatrie : étude prospective multicentrique

Contexte. - Une enquête qualitative exploratoire a montré que le nombre de patients éligibles et sollicités dans les essais en pédiatrie était peu objectivé ainsi que les refus. Objectif. - Estimer le nombre de refus de participation des familles dans les essais en pédiatrie et lier le taux de refus aux caractéristiques protocole, investigateur et patients. Matériel et méthodes. - Étude prospective multicentrique inter-CIC (réseau pédiatrique) d'une cohorte de protocoles. Pour chaque sollicitation à participer, des fiches patient, investigateur et protocole étaient remplies. Résultats. - L'étude a été réalisée de décembre 2005 à septembre 2007 sur quatre centres et a inclus 45 protocoles : 32 à promotion industrielle, 36 multicentriques, 19 essais cliniques, 33 avec prises de sang et six avec examens invasifs, 26 avec des déplacements spécifiques et 14 des hospitalisations supplémentaires. Sur ces protocoles, 170 investigateurs étaient référencés comme recruteurs et 86 (51 %) ont répondu au questionnaire : âge médian 42 ans, sex-ratio de 1, 13 sont investigateurs principal, 32 responsables pour le CIC et 50 investigateurs associés, 20 percevaient une rétribution versée au service dans 80 % des cas. La charge de travail médiane par investigateur était d'une heure par inclusion et 67 (78 %) bénéficiaient d'une aide d'une TEC. Au total, 1022 sollicitations ont été réalisées sur 36 protocoles (neuf protocoles n'ayant eu aucune sollicitation) et 334 refus (33 %) ont été enregistrés soit une médiane de 12 % (Q1Q3 : 0-28 %) de refus par protocole. Parmi les 36 protocoles, 16 n'ont enregistré aucun refus, représentant 147 sollicitations et les 20 autres protocoles ont eu un taux moyen de 38 % de refus. L'analyse explicative est en cours. Conclusion. - Le taux de refus de 12 % n'est pas différent de celui des essais adultes et semble dépendant du type d'étude. L'absence de sollicitation concerne 20 % des études

Relationship between microstructure and fracture types in a UNS S32205 duplex stainless steel

Duplex stainless steels are susceptible to the formation of sigma phase at high temperature which could potentially be responsible for catastrophic service failure of components. Thermal treatments were applied to duplex stainless steels in order to promote the precipitation of different fractions of sigma phase into a ferrite-austenite microstructure. Quantitative image analysis was employed to characterize the microstructure and Charpy impact tests were used in order to evaluate the mechanical degradation caused by sigma phase presence. The fracture morphology of the Charpy test specimens were thoroughly observed in SEM, looking for a correlation between the microstructure and the fracture types in UNS S32205 duplex stainless steel. The main conclusion is the strong embrittlement effect of sigma phase since it is possible to observe a transition from transgranular fracture to intergranular fracture as increases the percentage of sigma phase. Thus, the mixed modes of fracture are predominant in the present study with high dependence on sigma phase percentages obtained by different thermal treatments

Characterization of thermal oxide films formed on a duplex stainless steel by means of confocal-Raman microscopy and electrochemical techniques

In this work oxide films have been developed on the surface of a duplex stainless steel (UNS 1.4462) using high temperature confocal microscopy to follow their growth. The characteristics of these oxide films have been analyzed by means of weight-gain measurements, Raman microscopy and electrochemical techniques, namely potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results show an increase in the amount of oxides (particularly γ-Fe2O3 and Fe3O4) with temperature. Regarding the electrochemical properties of these films, the corrosion resistance of the film tends to be lower with the heat treatment temperature, probably due to a more porous and heterogeneous scale. Mott–Schottky plots show the n-type semiconductive behavior of the films with donor densities that decrease with the enhancement of the temperature.We wish to express our gratitude to MICINN (CTQ2009-07518) (UPVO8-3E-012), to Universitat Politecnica de Valencia (CEI-01-11), to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRM/S/100), and to Dr. Asuncion Jaime for her translation assistance.Sánchez Tovar, R.; Leiva García, R.; García Antón, J. (2015). Characterization of thermal oxide films formed on a duplex stainless steel by means of confocal-Raman microscopy and electrochemical techniques. Thin Solid Films. 576:1-10. https://doi.org/10.1016/j.tsf.2014.12.024S11057

Is There an Association between Long-Term Sick Leave and Disability Pension and Unemployment beyond the Effect of Health Status? – A Cohort Study

Background: Studies have shown that long-term sick leave is a strong predictor of disability pension. However, few have aimed to disentangle the effect of sick leave and of health status. The objective of this study was to investigate whether there is an association between long-term sick leave and disability pension and unemployment, when taking health status into account. Methods/Principal Findings: The study was based on the Stockholm Public Health Cohort, restricted to 13,027 employed individuals (45.9 % men) aged 18–59 in 2002 and followed until 2007. Hazard ratios (HR) with 95 % Confidence Interval (CI) were estimated by Cox regression models adjusting for socio-demographic factors and five measures of health status. Having been on long-term sick leave increased the risk of disability pension (HR 4.01; 95 % CI 3.19–5.05) and longterm unemployment (HR 1.45; 95 % CI 1.05–2.00), after adjustment for health status. The analyses of long-term sick leave due to specific illness showed that the increased risk for long-term unemployment was confined to the group on sick leave due to musculoskeletal (HR 1.70 95 % CI 1.00–2.89) and mental illness (HR 1.80 95 % CI 1.13–2.88) and further that there was an increased risk for short-term unemployment in the group on sick leave due to mental illness (HR1.57 95%CI 1.09–2.26). Conclusions/Significance: Long-term sick leave increases the risks of both disability pension and unemployment even when taking health status into account. The results support the hypothesis that long-term sick leave may start a process o

Effectiveness of early part-time sick leave in musculoskeletal disorders

<p>Abstract</p> <p>Background</p> <p>The importance of staying active instead of bed rest has been acknowledged in the management of musculoskeletal disorders (MSDs). This emphasizes the potential benefits of adjusting work to fit the employee's remaining work ability. Despite part-time sick leave being an official option in many countries, its effectiveness has not been studied yet. We have designed a randomized controlled study to assess the health effects of early part-time sick leave compared to conventional full-day sick leave. Our hypothesis is that if work time is temporarily reduced and work load adjusted at the early stages of disability, employees with MSDs will have less disability days and faster return to regular work duties than employees on a conventional sick leave.</p> <p>Methods/Design</p> <p>The study population will consist of 600 employees, who seek medical advice from an occupational physician due to musculoskeletal pain. The inclusion requires that they have not been on a sick leave for longer than 14 days prior to the visit. Based on the physician's judgement, the severity of the symptoms must indicate a need for conventional sick leave, but the employee is considered to be able to work part-time without any additional risk. Half of the employees are randomly allocated to part-time sick leave group and their work time is reduced by 40–60%, whereas in the control group work load is totally eliminated with conventional sick leave. The main outcomes are the number of days from the initial visit to return to regular work activities, and the total number of sick leave days during 12 and 24 months of follow-up. The costs and benefits as well as the feasibility of early part-time sick leave will also be evaluated.</p> <p>Conclusion</p> <p>This is the first randomised trial to our knowledge on the effectiveness of early part-time sick leave compared to conventional full-time sick leave in the management of MSDs. The data collection continues until 2011, but preliminary results on the feasibility of part-time sick leave will be available already in 2008. The increased knowledge will assist in better decision making process regarding the management of disability related to MSDs.</p> <p>Trial Registration</p> <p>International Standard Randomised Controlled Trial Number Register, register number ISRCTN30911719</p

Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques

When duplex stainless steels are heated, they can become sensitised and intermetallic phases can appear. In this work, samples of duplex stainless steel, UNS 1.4462, have been heated (850 degrees C for 1 and 2 h) in a heating unit that can be accommodated to a confocal microscope in order to study the morphological changes in-situ. The electrochemical behaviour of the samples has been analysed by means of conventional and localised electrochemical techniques. According to the results, there is a general decrease in the steel resistance to localised corrosion; this decrease can be related to defects in the formed passive film.We wish to express our gratitude to MICINN (CTQ2009-07518), to Universitat Politecnica de Valencia (CEI-01-11), to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRM/S/100), to Professor Alda Simoes and Andreia Marques for the help on LEIS measurements and to Dr. Asuncion Jaime for her translation assistance.Leiva García, R.; Fernandes, JS.; Muñoz-Portero, M.; Garcia-Anton, J. (2015). Study of the sensitisation process of a duplex stainless steel (UNS 1.4462) by means of confocal microscopy and localised electrochemical techniques. Corrosion Science. 94:327-341. https://doi.org/10.1016/j.corsci.2015.02.016S3273419