98 resultados para Sexually transmitted infections, Life course epidemiology, Sexual health, Women, Australia
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This thesis addresses the issue of the moving boundaries between family and friends' roles in personal networks, adopting a life-course perspective and using Switzerland as a case study. In a period of major changes in personal life happening in contemporary Western societies, understanding the organization of personal networks intertwined with the unfolding of individual life courses is of prime importance in facing new challenges with regard to social integration. The data stem from a representative national survey carried out in 2011 named Family tiMes, including 803 individuals born either in 1950-1955 or in 1970-1975. An innovative research design was adopted, combing cross-sectional ego-centered network data and retrospective longitudinal life-course data. The results show continuing boundaries between family and friends' roles and that family keeps a prominent role in personal networks despite the notable importance of friendship ties. One relationship stands out above all, that with the partner, followed quite a few steps behind by those with children. Regarding life courses, de-standardization tendencies were found in family formation and also a persistent gendering of occupational trajectories. Two kinds of life trajectories are particularly intertwined with personal networks, co-residence and partnership trajectories, both related to the unfolding of family life. In particular, transition to parenthood functions as a turning point in individuals' lives, deeply transforming their sociability. Finally, a twofold pluralization process was identified, affecting simultaneously the organization of personal networks and the unfolding of individual life courses. This thesis contributes to the literature on the sociology of family and personal life, and to fruitful interlinkage between the network approach and the life-course perspective.
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Changes in human lives are studied in psychology, sociology, and adjacent fields as outcomes of developmental processes, institutional regulations and policies, culturally and normatively structured life courses, or empirical accounts. However, such studies have used a wide range of complementary, but often divergent, concepts. This review has two aims. First, we report on the structure that has emerged from scientific life course research by focusing on abstracts from longitudinal and life course studies beginning with the year 2000. Second, we provide a sense of the disciplinary diversity of the field and assess the value of the concept of 'vulnerability' as a heuristic tool for studying human lives. Applying correspondence analysis to 10,632 scientific abstracts, we find a disciplinary divide between psychology and sociology, and observe indications of both similarities of-and differences between-studies, driven at least partly by the data and methods employed. We also find that vulnerability takes a central position in this scientific field, which leads us to suggest several reasons to see value in pursuing theory development for longitudinal and life course studies in this direction.
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Overall introduction.- Longitudinal studies have been designed to investigate prospectively, from their beginning, the pathway leading from health to frailty and to disability. Knowledge about determinants of healthy ageing and health behaviour (resources) as well as risks of functional decline is required to propose appropriate preventative interventions. The functional status in older people is important considering clinical outcome in general, healthcare need and mortality. Part I.- Results and interventions from lucas (longitudinal urban cohort ageing study). Authors.- J. Anders, U. Dapp, L. Neumann, F. Pröfener, C. Minder, S. Golgert, A. Daubmann, K. Wegscheider,. W. von Renteln-Kruse Methods.- The LUCAS core project is a longitudinal cohort of urban community-dwelling people 60 years and older, recruited in 2000/2001. Further LUCAS projects are cross-sectional comparative and interventional studies (RCT). Results.- The emphasis will be on geriatric medical care in a population-based approach, discussing different forms of access, too. (Dapp et al. BMC Geriatrics 2012, 12:35; http://www.biomedcentral.com/1471-2318/12/35): - longitudinal data from the LUCAS urban cohort (n = 3.326) will be presented covering 10 years of observation, including the prediction of functional decline, need of nursing care, and mortality by using a self-filling screening tool; - interventions to prevent functional decline do focus on first (pre-clinical) signs of pre-frailty before entering the frailty-cascade ("Active Health Promotion in Old Age", "geriatric mobility centre") or disability ("home visits"). Conclusions.- The LUCAS research consortium was established to study particular aspects of functional competence, its changes with ageing, to detect pre-clinical signs of functional decline, and to address questions on how to maintain functional competence and to prevent adverse outcome in different settings. The multidimensional data base allows the exploration of several further questions. Gait performance was exmined by GAITRite®-System. Supported by the Federal Ministry for Education and Research (BMBF Funding No. 01ET1002A). Part II.- Selected results from the lausanne cohort 65+ (Lc65 + ) Study (Switzerland). Authors.- Prof Santos-Eggimann Brigitte, Dr Seematter-Bagnoud Laurence, Prof Büla Christophe, Dr Rochat Stéphane. Methods.- The Lc65+ cohort was launched in 2004 with the random selection of 3054 eligible individuals aged 65 to 70 (birth year 1934-1938) in the non-institutionalized population of Lausanne (Switzerland). Results.- Information is collected about life course social and health-related events, socio-economics, medical and psychosocial dimensions, lifestyle habits, limitations in activities of daily living, mobility impairments, and falls. Gait performance are objectively measured using body-fixed sensors. Frailty is assessed using Fried's frailty phenotype. Follow-up consists in annual self-completed questionnaires, as well as physical examination and physical and mental performance tests every three years. - Lausanne cohort 65+ (Lc65 + ): design and longitudinal outcomes. The baseline data collection was completed among 1422 participants in 2004-2005 through self-completed questionnaires, face-to-face interviews, physical examination and tests of mental and physical performances. Information about institutionalization, self-reported health services utilization, and death is also assessed. An additional random sample (n = 1525) of 65-70 years old subjects was recruited in 2009 (birth year 1939-1943). - lecture no 4: alcohol intake and gait parameters: prevalent and longitudinal association in the Lc65+ study. The association between alcohol intake and gait performance was investigated.
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Les POCT (point of care tests) ont un grand potentiel d'utilisation en médecine infectieuse ambulatoire grâce à leur rapidité d'exécution, leur impact sur l'administration d'antibiotiques et sur le diagnostic de certaines maladies transmissibles. Certains tests sont utilisés depuis plusieurs années (détection de Streptococcus pyogenes lors d'angine, anticorps anti-VIH, antigène urinaire de S. pneumoniae, antigène de Plasmodium falciparum). De nouvelles indications concernent les infections respiratoires, les diarrhées infantiles (rotavirus, E. coli entérohémorragique) et les infections sexuellement transmissibles. Des POCT, basés sur la détection d'acides nucléiques, viennent d'être introduits (streptocoque du groupe B chez la femme enceinte avant l'accouchement et la détection du portage de staphylocoque doré résistant à la méticilline). POCT have a great potential in ambulatory infectious diseases diagnosis, due to their impact on antibiotic administration and on communicable diseases prevention. Some are in use for long (S. pyogenes antigen, HIV antibodies) or short time (S. pneumoniae antigen, P. falciparum). The additional major indications will be community-acquired lower respiratory tract infections, infectious diarrhoea in children (rotavirus, enterotoxigenic E. coli), and hopefully sexually transmitted infections. Easy to use, these tests based on antigen-antibody reaction allow a rapid diagnosis in less than one hour; the new generation of POCT relying on nucleic acid detection are just introduced in practice (detection of GBS in pregnant women, carriage of MRSA), and will be extended to many pathogens
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RésuméLa naissance du premier enfant est un événement normatif à l'origine de nombreux changements dans le parcours de vie des hommes et des femmes. La présente recherche s'intéresse à la transition à la parentalité en tant que moment à l'origine d'un processus de stratification sociale. Trois dimensions dépendantes sont étudiées du point de vue de leur changement: l'insertion professionnelle, le travail domestique et la qualité de la relation conjugale. Les concepts de divergence et de convergence interindividuelle, élaborés à partir de l'hypothèse des dés/avantages cumulatifs et de l'hypothèse alternative des effets compensatoires, sont utilisés pour opérationnaliser le changement qui se produit dans ces trois dimensions lors de la naissance du premier enfant.Les résultats montrent, dans un premier moment, la présence de divergences entre les hommes et les femmes dans chacune de ces trois dimensions. Ces divergences inter-sexe sont associées à des convergences entre les individus de même sexe. Les analyses se focalisent dans un deuxième moment, sur les divergences et convergences ultérieures qui se produisent entre individus du même sexe en fonction des ressources sociales, culturelles et économiques initiales. Quelles sont ainsi, par exemple, les mères qui ne diminuent pas leur taux d'occupation initial? Quels sont les pères qui réduisent moins que les autres leur investissement dans le travail domestique? Quels sont les parents qui connaissent une moindre diminution de la qualité de leur relation conjugale? Les réponses données à ces questions montrent comment le processus de stratification sociale au sein d'une cohorte doit être expliqué en relation avec le changement qui se produit lors d'une transition spécifique et non seulement en tant que résultat du simple passage du temps.AbstractThe birth of the first child is a normative event creating important changes in the life course of men and women. This research analyzes the transition to parenthood as a moment creating social stratification. Three dependent dimensions are studied in their change: the occupational career, the domestic labour and the conjugal relationship's quality. The concepts of interindividual divergences and convergence, conceived from the cumulative dis/advantage hypothesis and the alternative hypothesis of compensatory effects, are used to operationalize the change in these three dimensions after the birth of the first child.Results show that, firstly, divergences take place between men and women becoming parents in the three dependent dimensions. Inter-sex divergences are associated to convergence between same-sex individuals. Secondly, the analyses focus on further di/convergences taking place between same-sex individuals, in relation with the initial social, cultural and economical resources. Who are the mothers who will not reduce their initial occupational rates? Who are the fathers who will reduce less than the others their involvement in the domestic tasks? Who are the parents who will experience a less important reduction in their conjugal relationship's quality? The answers to these questions show how the process of social stratification within a cohort has to be explained in relation with the change taking place during a specific transition and not only as a result of the simple passage of time.
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An EC concerted action on the assessment of AIDS/HIV prevention strategies was conducted between 1989 and 1992. The aim of this concerted action (CA) was to bring together researchers who are active in this assessment field, make an initial appraisal of the results of AIDS prevention efforts, in various population groups in Europe and develop an assessment methodology. Five areas of study were selected for the CA: the population as a whole ("general population"), men who have sexual relations with other men, intravenous drug users, migrant populations, monitoring of sexually transmitted diseases (STDs) to determine changes in behaviour. For each of these areas, a working group composed of the leading researchers in the field in Europe was constituted and commissioned by the project administration and coordination team to collate and analyse data on prevention efforts and their assessment in different countries of Europe. This review presents the main results from the groups responsible in each area in the concerted action. A number of general conclusions from the results of this concerted action are drawn.
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General introductionThe Human Immunodeficiency/Acquired Immunodeficiency Syndrome (HIV/AIDS) epidemic, despite recent encouraging announcements by the World Health Organization (WHO) is still today one of the world's major health care challenges.The present work lies in the field of health care management, in particular, we aim to evaluate the behavioural and non-behavioural interventions against HIV/AIDS in developing countries through a deterministic simulation model, both in human and economic terms. We will focus on assessing the effectiveness of the antiretroviral therapies (ART) in heterosexual populations living in lesser developed countries where the epidemic has generalized (formerly defined by the WHO as type II countries). The model is calibrated using Botswana as a case study, however our model can be adapted to other countries with similar transmission dynamics.The first part of this thesis consists of reviewing the main mathematical concepts describing the transmission of infectious agents in general but with a focus on human immunodeficiency virus (HIV) transmission. We also review deterministic models assessing HIV interventions with a focus on models aimed at African countries. This review helps us to recognize the need for a generic model and allows us to define a typical structure of such a generic deterministic model.The second part describes the main feed-back loops underlying the dynamics of HIV transmission. These loops represent the foundation of our model. This part also provides a detailed description of the model, including the various infected and non-infected population groups, the type of sexual relationships, the infection matrices, important factors impacting HIV transmission such as condom use, other sexually transmitted diseases (STD) and male circumcision. We also included in the model a dynamic life expectancy calculator which, to our knowledge, is a unique feature allowing more realistic cost-efficiency calculations. Various intervention scenarios are evaluated using the model, each of them including ART in combination with other interventions, namely: circumcision, campaigns aimed at behavioral change (Abstain, Be faithful or use Condoms also named ABC campaigns), and treatment of other STD. A cost efficiency analysis (CEA) is performed for each scenario. The CEA consists of measuring the cost per disability-adjusted life year (DALY) averted. This part also describes the model calibration and validation, including a sensitivity analysis.The third part reports the results and discusses the model limitations. In particular, we argue that the combination of ART and ABC campaigns and ART and treatment of other STDs are the most cost-efficient interventions through 2020. The main model limitations include modeling the complexity of sexual relationships, omission of international migration and ignoring variability in infectiousness according to the AIDS stage.The fourth part reviews the major contributions of the thesis and discusses model generalizability and flexibility. Finally, we conclude that by selecting the adequate interventions mix, policy makers can significantly reduce the adult prevalence in Botswana in the coming twenty years providing the country and its donors can bear the cost involved.Part I: Context and literature reviewIn this section, after a brief introduction to the general literature we focus in section two on the key mathematical concepts describing the transmission of infectious agents in general with a focus on HIV transmission. Section three provides a description of HIV policy models, with a focus on deterministic models. This leads us in section four to envision the need for a generic deterministic HIV policy model and briefly describe the structure of such a generic model applicable to countries with generalized HIV/AIDS epidemic, also defined as pattern II countries by the WHO.
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Epidemiological studies show a prevalence of sexual abuse experience among girls from 14-33%. Although indicators of abuse are unspecific, the combination of several findings may be indicative: Somatic signs may be sexually transmitted diseases, vulvovaginal complaints. Psychosocial nonsexual indicators are abrupt behavioural changes, running away from home, eating disorders. Psychosexual signs are hypersexualisation of the language and behaviour, disturbed body image and gender identity. Indirect evidence of abuse is given not only in cases of old vaginal and anal lesions but also in situations, where deep tears of the hymen in the typical localization at the posterior part can be found. The workup and care for children in whom there is suspicion of abuse but no clear evidence asks for highly competent professionals in a multidisciplinary cooperation including pediatric gynecologists, child psychiatrists, children-protection groups and other specialists to avoid on one hand unjustified destabilisation or even destruction of familial structures but to assure on the other hand, that the child victims are treated and followed after in a short and long term comprehensive medical and psychosocial care.
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BACKGROUND: To determine male outpatient attenders' sexual behaviours, expectations and experience of talking about their sexuality and sexual health needs with a doctor. METHODS: A survey was conducted among all male patients aged 18-70, recruited from the two main medical outpatient clinics in Lausanne, Switzerland, in 2005-2006. The anonymous self-administered questionnaire included questions on sexual behaviour, HIV/STI information needs, expectations and experiences regarding discussion of sexual matters with a doctor. RESULTS: The response rate was 53.0% (N = 1452). The mean age was 37.7 years. Overall, 13.4% of patients were defined as at STI risk--i.e. having not consistently used condoms with casual partners in the last 6 months, or with a paid partner during the last intercourse--regarding their sexual behaviour in the last year. 90.9% would have liked their physician to ask them questions concerning their sexual life; only 61.4% had ever had such a discussion. The multivariate analysis showed that patients at risk tended to have the following characteristics: recruited from the HIV testing clinic, lived alone, declared no religion, had a low level of education, felt uninformed about HIV/AIDS, were younger, had had concurrent sexual partners in the last 12 months. However they were not more likely to have discussed sexual matters with their doctor than patients not at risk. CONCLUSION: Recording the sexual history and advice on the prevention of the risks of STI should become routine practice for primary health care doctors.
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Health-related quality of life (HRQoL) was evaluated in a sample of alcohol-dependent patients with the 36-item Medical Outcome Study Short-Form Health Survey (MOS-SF-36). The instrument was administered to 147 patients (77% males), aged 26-78, with a DSM-III-R diagnosis of alcohol dependence. The Hamilton Depression Scale (HDS), the Severity of Alcohol Dependence Questionnaire (SADQ), and the Addiction Severity Index (ASI) were also administered to the first 100 patients included in the study. The reliability and validity of the MOS-SF-36 were evaluated. Test-retest intraclass coefficients for a 10-day interval were in the range .65 to .79, whereas the Cronbach alpha coefficient indicated good internal consistency (range .70 to .89). Compared to scores observed in the general population, MOS-SF-36 scores for alcohol-dependent patients were relatively low (indicating worse perception of HRQoL), especially in the psychological and role dimensions (range 52/100 to 55/100), but were closer to populational values in the physical and functional dimensions (range 61/100 to 75/100)). The highest correlation between MOS-SF-36 dimensions and HDS was found in the MOS-SF-36 "mental health" dimension (r=-.56, p < .001); this dimension was also correlated highly with the psychiatric dimension of the ASI (r=-.73, p < .001). The eight dimensions of the MOS-SF-36 were 21% to 127% lower in patients with HDS greater than or equal to 16 (major depression) compared to those with HDS less than or equal to 7 (absence of depression). The MOS-SF-36 dimensions were 10% to 141% lower in patients with high "ASI alcohol" scores, indicating worse HRQoL profiles with a higher severity of alcohol dependence. The MOS-SF-36 presents good criteria for reliability and validity in alcohol-dependent patients. The results suggested that alcohol-dependent patients perceived their problems more as psychological than physical. The severity of alcohol dependence and depression seemed to influence the perception of HRQoL negatively.
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BACKGROUND: Used in conjunction with biological surveillance, behavioural surveillance provides data allowing for a more precise definition of HIV/STI prevention strategies. In 2008, mapping of behavioural surveillance in EU/EFTA countries was performed on behalf of the European Centre for Disease prevention and Control. METHOD: Nine questionnaires were sent to all 31 member States and EEE/EFTA countries requesting data on the overall behavioural and second generation surveillance system and on surveillance in the general population, youth, men having sex with men (MSM), injecting drug users (IDU), sex workers (SW), migrants, people living with HIV/AIDS (PLWHA), and sexually transmitted infection (STI) clinics patients. Requested data included information on system organisation (e.g. sustainability, funding, institutionalisation), topics covered in surveys and main indicators. RESULTS: Twenty-eight of the 31 countries contacted supplied data. Sixteen countries reported an established behavioural surveillance system, and 13 a second generation surveillance system (combination of biological surveillance of HIV/AIDS and STI with behavioural surveillance). There were wide differences as regards the year of survey initiation, number of populations surveyed, data collection methods used, organisation of surveillance and coordination with biological surveillance. The populations most regularly surveyed are the general population, youth, MSM and IDU. SW, patients of STI clinics and PLWHA are surveyed less regularly and in only a small number of countries, and few countries have undertaken behavioural surveys among migrant or ethnic minorities populations. In many cases, the identification of populations with risk behaviour and the selection of populations to be included in a BS system have not been formally conducted, or are incomplete. Topics most frequently covered are similar across countries, although many different indicators are used. In most countries, sustainability of surveillance systems is not assured. CONCLUSION: Although many European countries have established behavioural surveillance systems, there is little harmonisation as regards the methods and indicators adopted. The main challenge now faced is to build and maintain organised and functional behavioural and second generation surveillance systems across Europe, to increase collaboration, to promote robust, sustainable and cost-effective data collection methods, and to harmonise indicators.
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ABSTRACT Objectives: Patients with failed back surgery syndrome (FBSS) and chronic neuropathic pain experience levels of health-related quality of life (HRQoL) that are considerably lower than those reported in other areas of chronic pain. The aim of this article was to quantify the extent to which reductions in (leg and back) pain and disability over time translate into improvements in generic HRQoL as measured by the EuroQoL-5D and SF-36 instruments. Methods: Using data from the multinational Prospective, Randomized, Controlled, Multicenter Study of Patients with Failed Back Surgery Syndrome trial, we explore the relationship between generic HRQoL-assessed using two instruments often used in clinical trials (i.e., the SF-36 and EuroQol-5D)-and disease-specific outcome measures (i.e., Oswestry disability index [ODI], leg and back pain visual analog scale [VAS]) in neuropathic patients with FBSS. Results: In our sample of 100 FBSS patients, generic HRQoL was moderately associated with ODI (correlation coefficient: -0.462 to -0.638) and mildly associated with leg pain VAS (correlation coefficient: -0.165 to -0.436). The multilevel regression analysis results indicate that functional ability (as measured by the ODI) is significantly associated with HRQoL, regardless of the generic HRQoL instrument used. On the other hand, changes over time in leg pain were significantly associated with changes in the EuroQoL-5D and physical component summary scores, but not with the mental component summary score. Conclusions: Reduction in leg pain and functional disability is statistically significantly associated with improvements in generic HRQoL. This is the first study to investigate the longitudinal relationship between generic and disease-specific HRQoL of neuropathic pain patients with FBSS, using multinational data.
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This study on determinants of sexual protection behavior among HIV-positive gay men used the empirically tested information-motivation-behavioral skills (IMB) model. HIV-specific variables were added to the model to determine factors decisive for condom use with steady and casual partners. Data were collected using an anonymous, standardized self-administered questionnaire. Study participants were recruited at HIV outpatient clinics associated with the Eurosupport Study Group and the Swiss HIV Cohort Study. To identify factors associated with condom use, backward elimination regression analyses were performed. Overall, 838 HIV-infected gay men from 14 European countries were included in this analysis. About 53% of them reported at least one sexual contact with a steady partner; 62.5% had sex with a casual partner during the last 6Â months. Forty-three percent always used condoms with steady partners and 44% with casual partners. High self-efficacy and subjective norms in favor of condom-use were associated with increased condom use with casual and steady partners, whereas feeling depressed was associated with decreased condom use with casual partners. Condoms were used less often with HIV-positive partners. Self-efficacy as an important behavioral skill to perform protection behavior was influenced by lower perceived vulnerability, higher subjective norms, and more positive safer sex attitudes. The IMB-model constructs appeared to be valid; however, not all the model predictors could be determined as hypothesized. Besides the original IMB constructs, HIV-specific variables, including sexual partners' serostatus and mental health, explained condom use. Such factors should be considered in clinical interventions to promote "positive prevention."
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Järvholm and Co-workers (2009) proposed a conceptual model for research on working life. Models are powerful communication and decision tools. This model is strongly unidirectional and does not cover the mentioned interactions in the arguments.With help of a genealogy of work and of health it is shown that work and health are interactive and have to be analysed on the background of society.Key words: research model, work, health, occupational health, society, interaction, discussion paperRemodellierung der von Järvholm et al. (2009) vorgeschlagenen Forschungsperspektiven in Arbeit und GesundheitJärvholm und Kollegen stellten 2009 ein konzeptionelles Modell für die Forschung im Bereich Arbeit und Gesundheit vor. Modelle stellen kraftvolle Kommunikations- und Entscheidungsinstrumente dar. Die Einflussfaktoren im Modell verlaufen jedoch nur in einer Richtung und bilden die interaktiven Argumente im Text nicht ab. Mit Hilfe einer Genealogie der Begriffe Arbeit und Gesundheit wird aufgezeigt, dass Arbeit und Gesundheit sich gegenseitig beeinflussen und nur vor dem Hintergrund der jeweiligen gesellschaftlichen Kontextfaktoren zu analysieren sind.Introduction : After an interesting introduction about the objectives of research on working life, Järvholm and Co-workers (2009) manage to define a conceptual model for working life research out of a small survey of Occupational Safety and Health (OSH) definitions. The strong point of their model is the entity 'working life' including personal development, as well as career paths and aging. Yet, the model Järvholm et al. (2009) propose is strangely unidirectional; the arrows point from the population to working life, from there to health and to disease, as well as to productivity and economic resources. The diagram only shows one feed-back loop: between economic resources and health. We all know that having a chronic disease condition influences work and working capacity. Economic resources have a strong influence on work, too. Having personal economic resources will influence the kind of work someone accepts and facilitate access to continuous professional education. A third observation is that society is not present in the model, although this is less the case in the arguments. In fact, there is an incomprehensible gap between the arguments brought forth by Järvholm and co-workers and their reductionist model.Switzerland has a very low coverage of occupational health specialists. Switzerland is a long way from fulfilling the WHO's recommendations on workers' access to OSH services as described in its Global plan of action. The Institute for Work and Health (IST) in Lausanne is the only organisation which covers the major domains of OSH research that are occupational medicine, occupational hygiene, ergonomic and psychosocial research. As the country's sole occupational health institution we are forced to reflect the objectives of working life research so as not to waste the scare resources available.I will set out below a much shortened genealogy of work and of health, with the aim of extending Järvholm et al's (2009) analyses on the perspectives of working life research in two directions. Firstly towards the interactive nature of work and health and the integration of society, and secondly towards the question of what working life means or where working life could be situated.Work, as we know it today - paid work regulated by a contract as the basis for sustaining life and as a base for social rights - was born in modern era. Therefore I will start my genealogy in the pre-modern era, focus on the important changes that occurred during industrial revolution and the modern era and end in 2010 taking into account the enormous transformations of the past 20-30 years. I will put aside some 810 years of advances in science and technology that have expanded the world's limits and human understanding, and restrict my genealogy to work and to health/body implicating also the societal realm. [Author]
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BACKGROUND: Serosorting is practiced by men who have sex with men (MSM) to reduce human immunodeficiency virus (HIV) transmission. This study evaluates the prevalence of serosorting with casual partners, and analyses the characteristics and estimated numbers of serosorters in Switzerland 2007-2009. METHODS: Data were extracted from cross-sectional surveys conducted in 2007 and 2009 among self-selected MSM recruited online, through gay newspapers, and through gay organizations. Nested models were fitted to ascertain the appropriateness of pooling the datasets. Multiple logistic regression analysis was performed on pooled data to determine the association between serosorting and demographic, lifestyle-related, and health-related factors. Extrapolations were performed by applying proportions of various types of serosorters to Swiss population data collected in 2007. RESULTS: A significant and stable number of MSM (approximately 39% in 2007 and 2009) intentionally engage in serosorting with casual partners in Switzerland. Variables significantly associated with serosorting were: gay organization membership (aOR = 1.67), frequent internet use for sexual encounters (aOR = 1.71), having had a sexually transmitted infection (STI) at any time in the past 12 months (aOR = 1.70), HIV-positive status (aOR = 0.52), regularly frequenting sex-on-premises venues (aOR = 0.42), and unprotected anal intercourse (UAI) with partners of different or unknown HIV status in the past 12 months (aOR = 0.22). Approximately one-fifth of serosorters declared HIV negativity without being tested in the past 12 months; 15.8% reported not knowing their own HIV status. CONCLUSION: The particular risk profile of serosorters having UAI with casual partners (multiple partners, STI history, and inadequate testing frequency) requires specific preventive interventions tailored to HIV status.