No description available.

Masters Research - Master of Philosophy (MPhil) / The psychosocial stress of social conflict contributes to the development of depression and anxiety in those individuals vulnerable to its effects, yet the factors that contribute to vulnerability remain unclear. Researchers investigating factors such as behaviour and physiology have used the animal resident/intruder social conflict model whereby a young male rodent (intruder) is placed into the home cage of an older male (resident) that is trained to attack and defeat all intruders. Findings reported previously have shown that defeated intruders displayed medium to longer-term stress-related changes in behaviour and physiology, with considerable variability in the severity of these changes reported from one individual to another. Interestingly, a reduction in severity of behavioural and physiological changes was associated most significantly with intruders that deployed ‘active coping’ behaviours during the social defeat interaction than animals that deployed ‘passive coping’. However, these findings do not describe the short-term effects, raising the question; does coping style also influence the short-term stress response? We investigated the relationship between coping behaviour adopted by intruders during a 10 minute social conflict culminating in defeat and both acute peak plasma corticosterone (CORT) stress hormone levels and number of cells expressing Fos protein in eight brain regions. Our investigations revealed that higher levels of fight and guard behaviours were associated with lower peak plasma CORT levels compared to ready submission, and that higher levels of fight were associated with fewer numbers of Fos-ir cells in prefrontal cortex (PFC), amygdala (Am), and paraventricular nucleus (PVN) brain regions. In general terms, these findings indicate that coping behaviour deployed during social conflict influences the endocrine and neurobiological elements of the acute phase of the HPA axis response to psychosocial stress. Intruders that deploy an ‘active’ coping style including fight behaviours display significantly smaller physiological and neurobiological alterations in the acute response than intruders that deploy a ‘passive’ coping style during social conflict. These results demonstrate that the vulnerability to the effects of psychosocial stress are ameliorated by actively engaging with the perpetrator rather than passively taking the attack, and that adopting the behaviour fight is most protective. Further elucidation of the neural mechanisms that underpin the reduction in stress-induced effects is warranted.

Master of Public Health / Department of Kinesiology / Emily Mailey / INTRODUCTION: Research has focused on the relationship between socioeconomic status and physical activity, yet there are limited examinations which directly address social groups dealing with major issues associated with insufficient income. Studies have neglected the role of psychosocial stressors, such as financial stress, food insecurity, availability of government assistance programs, as well as psychological distress relative to the relationship between physical activity and low-income status. The purposes of this study were threefold: 1) to describe the multidimensional characteristics of life among low-income populations; 2) to examine how psychosocial stressors and health conditions vary across subsets of low-income groups; and 3) to examine the relationship among income, psychological distress and physical activity within low-income populations. METHODS: Data from the 2015 National Health Interview Survey (NHIS) were analyzed for the purposes of this investigation. Descriptive statistics were calculated for the low-income status individuals who provide complete data for all variables of interest to this study. A series of chi-square analyses were conducted to determine whether key psychosocial stressors, health behaviors, and health conditions differed by low-income (FIPR) groups. Two stepwise logistic regression analyses were conducted to examine these factors and their relationships with moderate-intensity (MPA) and vigorous (VPA)-intensity physical activity. RESULTS: Overall, women made up 58.5% of the sample size. Blacks/African Americans accounted for 20.6% of the sample, yet 28.0% of FIPR Group 1 identified as Black/African American. FIPR Group 1 was disproportionately unemployed, with 63.5% unemployed compared to 46.9% for the sample. One-quarter (25.9%) of the entire sample reported severe psychological distress, yet 33.9% of FIPR Group 1 and 30.8% of FIPR Group 2 reported severe distress. Nearly three-quarters (70%) of the sample was overweight or obese and 44.2% lived with at least one chronic disease at the time the survey was taken. Overall, 67.9% of the sample reported zero minutes of VPA and 51.3% reported zero minutes of MPA. Both psychological distress and income showed significant relationships with VPA. Psychological distress remained significantly associated with VPA after controlling for all covariates; however, income was no longer related to VPA after demographic and health-related variables were added to the model. Income was not related to MPA. Psychological distress demonstrated a weak relationship with MPA before the other covariates were added to the model, at which point the relationship became non-significant. Only the relationship between psychological distress and VPA was significant in the final models. Although some of the psychosocial stressor, demographic, and health-related variables contributed to the relationships between income, physical activity, and psychological distress, these variables explained only a small portion of the variance in both MPA and VPA. CONCLUSION: Low-income individuals are faced with difficult decisions and are limited in the choices they can make to improve health. It is important to understand the multidimensional characteristics of life under limited income to better serve and improve the health of low-income populations. Further study of the relationships among income, physical activity and psychological distress is needed to further this understanding.

<p>Fahlén, G. (2008). Aspects on the Effort-reward Imbalance model of psychosocial stress in the work environments. Sundsvall, Sweden: Mid Sweden University, Department of Health Sciences. ISBN 978-91-85317-94-3.</p><p>Since the late 1970s, work related stress has increasingly been recognized as an important determinant for ill-health and disease. One of the most influential stress models is the Effort-Reward Imbalance model (ERI), which stipulates that an imbalance between the perceived effort spent at work and rewards received results in noxious stress. Those with a coping behaviour called Work-related Overcommitment (WOC), including an inability to withdraw from work obligations are especially vulnerable. The model has shown strong explanatory value for a large numbers of harmful health outcomes.</p><p>The general aim of this thesis was to contribute to the development of the ERI model by exploring the properties of this model in relation to its theoretical assumptions, construct, and application and to improve the knowledge of validity of the ERI-model.</p><p>The study sample that was used in three papers emanated from the WOLF study (Work, Lipids and Fibrinogen). The analyses were confined to the subset of individuals who answered the ERI questions (n=1174) with complete answers. In one paper, data from the SKA study (Sick leave, Culture and Attitudes) were used and they comprised all employees at the Swedish Social Insurance Agency responsible for management and compensation of illness in the working population (n=5700). All data are based on questionnaires.</p><p>The results indicate that ERI and WOC are risk factors for sleep disturbances and fatigue. A palpable threshold effect was seen between quartile three and four. Since these symptoms are strongly stress related, our results support the utility of the ERI and WOC scales in assessing stress in working life.</p><p>Agreement between single questions in the original and an approximate instrument for measuring ERI were low, whereas the agreement between the two ERI scales was reasonable. When approximate instruments are used, questions and scales must be presented thoroughly to facilitate comparisons and the results should be interpreted with caution. Today there are no reasons to use such instruments in the ERI model.</p><p>One statement in the ERI model is that individuals with the coping behaviour characterised as WOC are particularly vulnerable to an imbalance between perceived effort and reward; i.e., that ERI and WOC interact. No such effect was shown in relation to disturbed sleep and fatigue. There is no convincing evidence that ERI and WOC interact in synergy. Analysis demonstrated that WOC was relatively stable in perceived unchanged conditions as measured by the original, more comprehensive instrument as well as by the present, shortened instrument. Positively or negatively perceived changes in ERI correspond to changes in WOC. This result suggests that WOC, at least in part, may act as not only a coping strategy but also as an outcome from ERI. Taken together, these results concerning WOC, suggest that studies to clarify the role of the WOC dimension are needed.</p><p>The ERI model states that, when individuals stay in unfavourable conditions characterised as ERI, because there are few alternatives on the labour market or when the individual is at risk of being laid off or of facing downward mobility, they are in a “locked in position” (LIP). A strong association between LIP and ERI was shown, supporting this statement.</p> / <p>Fahlén, G. (2008). Aspects on the Effort-reward Imbalance model of psychosocial stress in the work environments. Sundsvall, Sweden: Mid Sweden University, Department of Health Sciences. ISBN 978-91-85317-94-3.</p><p>Arbetsrelaterad stress har sedan slutat av sjuttiotalet alltmer blivit uppmärksammat som en viktig bestämningsfaktor för ohälsa. En av de mest inflytelserika stressmodellerna är Ansträngning-belönings modellen (Effort-reward imbalance, ERI) som stipulerar att en obalans mellan ansträngning och belöning i arbetet orsakar en skadlig stress och att de som har ett särskilt coping-beteende som kännetecknas bland annat av oförmåga att dra sig tillbaka från sitt arbete (Work related overcommitment WOC) är särskilt sårbara. Modellen har visat ett starkt förklaringsvärde för många negativa hälsoutfall.</p><p>Det övergripande syftet med avhandlingen var att bidra till utvecklingen av ERI-modellen genom att utforska modellens egenskaper i relation till de teoretiska antagandena, uppbyggnad och tillämpning samt att öka kunskapen om modellens validitet.</p><p>Den epidemiologiska studie som användes i tre artiklar var WOLF-studien (WOrk, Lipids and Fibrinogen) där analyserna genomfördes på den delmängd som hade svarat på ERI-frågorna (n=1174) och som hade kompletta svar. För en artikel användes material från SKA-studien (Sjukskrivning, Kultur och Attityder) och omfattade de som arbetade med ohälsoärenden vid Försäkringskassan (n=5700) i samtliga fall användes data från frågeformulär.</p><p>Resultaten visade att ERI och WOC utgör riskfaktorer för störd sömn och dagtrötthet. En tydlig tröskeleffekt kunde skönjas mellan tredje och fjärde kvartilen. Eftersom dessa symptom är starkt stressrelaterade, gav resultaten stöd för användbarheten av ERI och WOC instrumenten för att skatta stress i arbetslivet.</p><p>Överensstämmelsen mellan enskilda frågor i orginalinstrumentet för ERI och ett approximativt var låg, medan överensstämmelsen mellan de två ERI skalorna bedömdes som rimlig. När approximativa instrument används bör frågor och skalor presenteras utförligt för att jämförelser ska underlättas och resultaten bör tolkas med försiktighet.</p><p>En utgångspunkt i ERI-modellen är att individer som har ett coping-beteende som karakteriseras som WOC är särskilt sårbara för en obalans mellan ansträngning och belöning, d.v.s. att ERI och WOC interagerar i synergi. Ingen sådan effekt kunde styrkas i relation till störd sömn och dagtrötthet. Det saknas också övertygande bevis för att en sådan effekt finns. WOC-måttet är relativt stabilt i oförändrade arbetsförhållanden i såväl orginalinstrumentet som i det nuvarande förkortade. Upplevda positiva eller negativa förändringar i ERI påverkade WOC i samma riktning. Resultaten indikerade att WOC, åtminstone delvis kan utgöra ett utfall av ERI, inte endast en copingstrategi. Dessa resultat gör att studier för att tydliggöra WOC-dimensionens roll i ERI modellen är önskvärda.</p><p>En annan utgångspunkt i modellen är att en av de situationer man stannar i ogynnsamma arbetsförhållanden kännetecknade av ERI, är att man har små möjligheter att byta arbete beroende på att man har få möjligheter på arbetsmarknaden eller är utsatt för risk att bli uppsagd eller att få sämre arbete, man är ”inlåst”. Resultaten visade på en stark association mellan inlåsning och ERI och gav därmed stöd åt antagandet.</p>

Fahlén, G. (2008). Aspects on the Effort-reward Imbalance model of psychosocial stress in the work environments. Sundsvall, Sweden: Mid Sweden University, Department of Health Sciences. ISBN 978-91-85317-94-3. Since the late 1970s, work related stress has increasingly been recognized as an important determinant for ill-health and disease. One of the most influential stress models is the Effort-Reward Imbalance model (ERI), which stipulates that an imbalance between the perceived effort spent at work and rewards received results in noxious stress. Those with a coping behaviour called Work-related Overcommitment (WOC), including an inability to withdraw from work obligations are especially vulnerable. The model has shown strong explanatory value for a large numbers of harmful health outcomes. The general aim of this thesis was to contribute to the development of the ERI model by exploring the properties of this model in relation to its theoretical assumptions, construct, and application and to improve the knowledge of validity of the ERI-model. The study sample that was used in three papers emanated from the WOLF study (Work, Lipids and Fibrinogen). The analyses were confined to the subset of individuals who answered the ERI questions (n=1174) with complete answers. In one paper, data from the SKA study (Sick leave, Culture and Attitudes) were used and they comprised all employees at the Swedish Social Insurance Agency responsible for management and compensation of illness in the working population (n=5700). All data are based on questionnaires. The results indicate that ERI and WOC are risk factors for sleep disturbances and fatigue. A palpable threshold effect was seen between quartile three and four. Since these symptoms are strongly stress related, our results support the utility of the ERI and WOC scales in assessing stress in working life. Agreement between single questions in the original and an approximate instrument for measuring ERI were low, whereas the agreement between the two ERI scales was reasonable. When approximate instruments are used, questions and scales must be presented thoroughly to facilitate comparisons and the results should be interpreted with caution. Today there are no reasons to use such instruments in the ERI model. One statement in the ERI model is that individuals with the coping behaviour characterised as WOC are particularly vulnerable to an imbalance between perceived effort and reward; i.e., that ERI and WOC interact. No such effect was shown in relation to disturbed sleep and fatigue. There is no convincing evidence that ERI and WOC interact in synergy. Analysis demonstrated that WOC was relatively stable in perceived unchanged conditions as measured by the original, more comprehensive instrument as well as by the present, shortened instrument. Positively or negatively perceived changes in ERI correspond to changes in WOC. This result suggests that WOC, at least in part, may act as not only a coping strategy but also as an outcome from ERI. Taken together, these results concerning WOC, suggest that studies to clarify the role of the WOC dimension are needed. The ERI model states that, when individuals stay in unfavourable conditions characterised as ERI, because there are few alternatives on the labour market or when the individual is at risk of being laid off or of facing downward mobility, they are in a “locked in position” (LIP). A strong association between LIP and ERI was shown, supporting this statement. / Fahlén, G. (2008). Aspects on the Effort-reward Imbalance model of psychosocial stress in the work environments. Sundsvall, Sweden: Mid Sweden University, Department of Health Sciences. ISBN 978-91-85317-94-3. Arbetsrelaterad stress har sedan slutat av sjuttiotalet alltmer blivit uppmärksammat som en viktig bestämningsfaktor för ohälsa. En av de mest inflytelserika stressmodellerna är Ansträngning-belönings modellen (Effort-reward imbalance, ERI) som stipulerar att en obalans mellan ansträngning och belöning i arbetet orsakar en skadlig stress och att de som har ett särskilt coping-beteende som kännetecknas bland annat av oförmåga att dra sig tillbaka från sitt arbete (Work related overcommitment WOC) är särskilt sårbara. Modellen har visat ett starkt förklaringsvärde för många negativa hälsoutfall. Det övergripande syftet med avhandlingen var att bidra till utvecklingen av ERI-modellen genom att utforska modellens egenskaper i relation till de teoretiska antagandena, uppbyggnad och tillämpning samt att öka kunskapen om modellens validitet. Den epidemiologiska studie som användes i tre artiklar var WOLF-studien (WOrk, Lipids and Fibrinogen) där analyserna genomfördes på den delmängd som hade svarat på ERI-frågorna (n=1174) och som hade kompletta svar. För en artikel användes material från SKA-studien (Sjukskrivning, Kultur och Attityder) och omfattade de som arbetade med ohälsoärenden vid Försäkringskassan (n=5700) i samtliga fall användes data från frågeformulär. Resultaten visade att ERI och WOC utgör riskfaktorer för störd sömn och dagtrötthet. En tydlig tröskeleffekt kunde skönjas mellan tredje och fjärde kvartilen. Eftersom dessa symptom är starkt stressrelaterade, gav resultaten stöd för användbarheten av ERI och WOC instrumenten för att skatta stress i arbetslivet. Överensstämmelsen mellan enskilda frågor i orginalinstrumentet för ERI och ett approximativt var låg, medan överensstämmelsen mellan de två ERI skalorna bedömdes som rimlig. När approximativa instrument används bör frågor och skalor presenteras utförligt för att jämförelser ska underlättas och resultaten bör tolkas med försiktighet. En utgångspunkt i ERI-modellen är att individer som har ett coping-beteende som karakteriseras som WOC är särskilt sårbara för en obalans mellan ansträngning och belöning, d.v.s. att ERI och WOC interagerar i synergi. Ingen sådan effekt kunde styrkas i relation till störd sömn och dagtrötthet. Det saknas också övertygande bevis för att en sådan effekt finns. WOC-måttet är relativt stabilt i oförändrade arbetsförhållanden i såväl orginalinstrumentet som i det nuvarande förkortade. Upplevda positiva eller negativa förändringar i ERI påverkade WOC i samma riktning. Resultaten indikerade att WOC, åtminstone delvis kan utgöra ett utfall av ERI, inte endast en copingstrategi. Dessa resultat gör att studier för att tydliggöra WOC-dimensionens roll i ERI modellen är önskvärda. En annan utgångspunkt i modellen är att en av de situationer man stannar i ogynnsamma arbetsförhållanden kännetecknade av ERI, är att man har små möjligheter att byta arbete beroende på att man har få möjligheter på arbetsmarknaden eller är utsatt för risk att bli uppsagd eller att få sämre arbete, man är ”inlåst”. Resultaten visade på en stark association mellan inlåsning och ERI och gav därmed stöd åt antagandet.

The role of stress (both psychosocial and oxidative) in the pathophysiology of several chronic diseases has been documented and has become a focus for chronic disease prevention and management. Although, psychosocial stress (PS) and oxidative stress (OS) have different mechanisms through which they impact health, they both cause physiological imbalance which might subsequently lead to a disease state. Laboratory and observational studies have linked both stresses to the pathophysiology of diabetes mellitus (DM) and hypertension. However, findings from previous studies have not been entirely consistent and results have varied based on the study population and the stress-measurement tool used. Given the gaps in the literature, three studies were conducted to examine: (1) the relationship between PS and glycemic control; (2) the association between PS and estimated glomerular filtration rate (eGFR); and (3) the association between OS and hypertension among adults. In the first two studies, a longitudinal data from Kaiser Permanente Georgia (KPGA) survey on Health and Healthy Behaviors linked to patients’ laboratory and pharmacy records was used. In the third study a cross-sectional data from Study on Race, Stress and Hypertension was used. The first study examined the association between baseline measure of work-related PS and glycemic control using both cross-sectional and longitudinal designs. None of the four PS sub-scales or the overall PS measure at the work environment was significantly associated with glycemic control at either study baseline or over time. The second study examined the association between general measures of PS and changes in estimated glomerular filtration rate (eGFR) over time in a structural equation model framework. No significant direct association was observed between general PS measure and eGFR decline. However, age, race, mean arterial pressure and insulin use were found to be associated with eGFR decline. The third study examined the association between hypertension and: 1) four markers of OS (F2-Isoprostanes, Fluorescent oxidative products, copy number of mitochondrial DNA and Gamma-tocopherol); and 2) plasma nutrient based oxidative balance score (OBS). The OBS was inversely associated with hypertension, but none of the OS markers was significantly associated with hypertension after adjusting for study covariates. The current work highlights some of methodological issues in the assessment of PS to examine their relationship with DM control and complications. The study also highlights the need for more future studies to be conducted to confirm the association between OBS and hypertension, preferably longitudinal studies. If future studies confirm this finding, then the mechanisms by which OBS may influence risk of hypertension would need to be explored further.

Low back pain (LBP) is a common occupational problem and continues to be the leading cause of occupational disability.  Among diverse known risk factors, sitting is commonly considered as an important exposure related to LBP.  Both modern living and contemporary work involve increased sedentary lifestyles, including more frequent and prolonged sitting.  At present, however, the causal role of sitting on LBP development is controversial due to the contribution of several moderating factors (e.g., task demands, duration of exposures, and presence of muscle fatigue).  A few studies have assessed low back loads in seated postures, but none has investigated the effects of prolonged sitting or time-dependent variations on spinal structure and spinal loading.  Adverse effects of muscle fatigue on low back pain are well documented, yet the specific relationship between muscle fatigue and sitting-related low back pain are not fully established.  In addition to these fundamental limitations in our understanding of the physical consequences of sitting, there is also little evidence regarding the effects of task requirements on muscle fatigue and spine loading.   Therefore, the main objectives of this work were, in the context of sitting, to: 1) develop and evaluate a method to assess paraspinal muscle fatigue using electrical stimulation; 2) develop and evaluate a method (model) to quantify biomechanical loads on the lumbar spine in a seated posture; and 3) quantify the effects of prolonged seated tasks on low back loads, body discomfort, and localized muscle fatigue (LMF).  The primary hypothesis was that exposure to sitting-related LBP risks is influenced by task requirements and sitting duration.   A muscle stimulation protocol was developed to measure stimulation responses in the lumbar extensors.  A stimulation protocol, which included one conditioning train along with three 16-second stimulation train at 2 Hz, was recommended as appropriate to measure those muscles potentially fatigued during prolonged seated tasks.  A three-dimensional, sitting-specific, fatigue-sensitive, time-dependent, electromyography (EMG)-based biomechanical model of the trunk was developed to investigate the effects of seated tasks and time-dependent variations on lumbosacral loading during sitting. Reasonable levels of correspondence were found between measured and predicted lumbosacral moments under a range of seated tasks.  Lastly, the effects of prolonged sitting and psychosocial work stress on low back were quantitatively identified.  Only prolonged sitting significantly increased trunk flexion angles and led to muscle fatigue.  Relatively weak correlations were found between subjective and objective measures, though the two fatigue measurement methods (based on EMG and stimulated responses) showed a good level of correspondence.   Overall, this work provides a quantitative assessment of biomechanical exposures associated with seated tasks.  The methods developed in this work make a contribution in terms of measurement/modeling approaches that can be used to assess LBP-relevant risks during prolonged sitting.  The results of this work provide a better understanding of the effects of prolonged sitting on the risk of developing sitting-related LBP.  Finally, results regarding the influences of prolonged sitting and psychosocial demands can be used to guide future job design. / Ph. D.

No description available.

No description available.

No description available.