| 1. |
- Beaven, C. Martyn, et al.
(författare)
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A Comparison of Blue Light and Caffeine Effects on Cognitive Function and Alertness in Humans
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10, s. e76707-
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Tidskriftsartikel (refereegranskat)abstract
- The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of similar to 40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention.
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| 2. |
- Beaven, Martyn, et al.
(författare)
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Physiological comparison of concentric and eccentric arm cycling in males and females
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:9, s. Art. no. e112079-
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Tidskriftsartikel (refereegranskat)abstract
- Lower body eccentric exercise is well known to elicit high levels of muscular force with relatively low cardiovascular and metabolic strain. As a result, eccentric exercise has been successfully utilised as an adaptive stressor to improve lower body muscle function in populations ranging from the frail and debilitated, to highly-trained individuals. Here we investigate the metabolic, cardiorespiratory, and energy costs of upper body eccentric exercise in a healthy population. Seven men and seven women performed 4-min efforts of eccentric (ECC) or concentric (CON) arm cycling on a novel arm ergometer at workloads corresponding to 40, 60, and 80% of their peak workload as assessed in an incremental concentric trial. The heart rate, ventilation, cardiac output, respiratory exchange ratio, and blood lactate concentrations were all clearly greater in CON condition at all of the relative workloads (all p<0.003). Effect size calculations demonstrated that the magnitude of the differences in VO2 and work economy between the ECC and CON exercise ranged from very large to extremely large; however, in no case did mechanical efficiency (ηMECH) differ between the conditions (all p>0.05). In contrast, delta efficiency (ηΔ), as previously defined by Coyle and colleagues in 1992, demonstrated a sex difference (men>women; p<0.05). Sex differences were also apparent in arteriovenous oxygen difference and heart rate during CON. Here, we reinforce the high-force, low cost attributes of eccentric exercise which can be generalised to the muscles of the upper body. Upper body eccentric exercise is likely to form a useful adjunct in debilitative, rehabilitative, and adaptive clinical exercise programs; however, reports of a shift towards an oxidative phenotype should be taken into consideration by power athletes. We suggest delta efficiency as a sensitive measure of efficiency that allowed the identification of sex differences.
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| 3. |
- Buxton, Jessica L., et al.
(författare)
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Multiple Measures of Adiposity Are Associated with Mean Leukocyte Telomere Length in the Northern Finland Birth Cohort 1966
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:6, s. Art. no. e99133-
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Tidskriftsartikel (refereegranskat)abstract
- Studies of leukocyte telomere length (LTL) and adiposity have produced conflicting results, and the relationship between body mass index (BMI) and telomere length throughout life remains unclear. We therefore tested association of adult LTL measured in 5,598 participants with: i) childhood growth measures (BMI and age at adiposity rebound (AR)); ii) change in BMI from childhood to adulthood and iii) adult BMI, waist-to-hip ratio (WHR), body adiposity index (BAI). Childhood BMI at AR was positively associated with LTL at 31 years in women (P = 0.041). Adult BMI and WHR in both men (P = 0.025 and P = 0.049, respectively) and women (P = 0.029 and P = 0.008, respectively), and BAI in women (P = 0.021) were inversely associated with LTL at 31 years. An increase in standardised BMI between early childhood and adulthood was associated with shorter adult LTL in women (P = 0.008). We show that LTL is inversely associated with multiple measures of adiposity in both men and women. Additionally, BMI increase in women from childhood to adulthood is associated with shorter telomeres at age 31, potentially indicating accelerated biological ageing.
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| 4. |
- Collste, Olov, et al.
(författare)
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No Myocardial Vulnerability to Mental Stress in Takotsubo Stress Cardiomyopathy
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:4, s. Art. no. e93697-
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Due to the frequent use of coronary angiography the awareness of Takotsubo stress cardiomyopathy (TSC) has increased although the exact pathophysiology of TSC is still largely unknown. Our objective was to investigate the effects of mental stress on myocardial function, heart rate variability (HRV) and salivary cortisol (SC) in TSC patients. Design: This study is a case-control study and a sub-study of the Stockholm Myocardial Infarction with Normal Coronaries (SMINC) study. Setting: Mental stress test was performed more than 6 months after the acute event in TSC patients and age- and sex-matched controls. Standard echocardiography and tissue Doppler imaging (TDI) - derived time-phases of cardiac cycle were recorded to calculate myocardial performance index (MPI) to assess ventricular function before and during mental stress. Holter-ECG recording was made to estimate HRV before, during and after mental stress. SC was measured at baseline, before and 20 minutes after mental stress. Subjects: Twenty-two TSC patients and 22 sex-and age- matched controls were recruited from the SMINC-study and investigated with a mental stress test. All TSC patients had a previous normal cardiovascular magnetic resonance investigation. Results: There were no significant differences at rest or during mental stress for left and right ventricular MPI or other standard diastolic variables between TSC patients and controls. HRV did not differ between TSC patients and controls. There was a trend towards less increase in SC after mental stress in TSC patients compared to controls. Conclusion: Mental stress did not induce a significant difference in myocardial function or HRV response between TSC and controls. Moreover, no significant difference could be seen in SC response at baseline, during or after mental stress. This study indicates that myocardial vulnerability to mental stress does not persist in TSC patients.
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| 5. |
- Darlow, Hanna, et al.
(författare)
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Do changes in the pace of events affect one-off judgments of duration?
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:3, s. e59847-
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Tidskriftsartikel (refereegranskat)abstract
- Five experiments examined whether changes in the pace of external events influence people's judgments of duration. In Experiments 1a–1c, participants heard pieces of music whose tempo accelerated, decelerated, or remained constant. In Experiment 2, participants completed a visuo-motor task in which the rate of stimulus presentation accelerated, decelerated, or remained constant. In Experiment 3, participants completed a reading task in which facts appeared on-screen at accelerating, decelerating, or constant rates. In all experiments, the physical duration of the to-be-judged interval was the same across conditions. We found no significant effects of temporal structure on duration judgments in any of the experiments, either when participants knew that a time estimate would be required (prospective judgments) or when they did not (retrospective judgments). These results provide a starting point for the investigation of how temporal structure affects one-off judgments of duration like those typically made in natural settings.
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| 6. |
- Elwér, Sofia, 1979-, et al.
(författare)
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Patterns of gender equality at workplaces and psychological distress
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Research in the field of occupational health often uses a risk factor approach which has been criticized by feminist researchers for not considering the combination of many different variables that are at play simultaneously. To overcome this shortcoming this study aims to identify patterns of gender equality at workplaces and to investigate how these patterns are associated with psychological distress. Questionnaire data from the Northern Swedish Cohort (n=715) have been analysed and supplemented with register data about the participants’ workplaces. The register data were used to create gender equality indicators of women/men ratios of number of employees, educational level, salary and parental leave. Cluster analysis was used to identify patterns of gender equality at the workplaces. Differences in psychological distress between the clusters were analysed by chi-square test and logistic regression analyses, adjusting for individual socio-demographics and previous psychological distress. The cluster analysis resulted in six distinctive clusters with different patterns of gender equality at the workplaces that were associated to psychological distress for women but not for men. For women the highest odds of psychological distress was found on traditionally gender unequal workplaces. The lowest overall occurrence of psychological distress as well as same occurrence for women and men was found on the most gender equal workplaces. The results from this study support the convergence hypothesis as gender equality at the workplace does not only relate to better mental health for women, but also more similar occurrence of mental ill-health between women and men. This study highlights the importance of utilizing a multidimensional view of gender equality to understand its association to health outcomes. Health policies need to consider gender equality at the workplace level as a social determinant of health that is of importance for reducing differences in health outcomes for women and men.
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| 7. |
- Hagström, Åsa, et al.
(författare)
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Semi-selective fatty acyl reductases from four Heliothine moths influence the specific pheromone composition
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:e37230, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sex pheromones are essential in moth mate communication. Information on pheromone biosynthetic genes and enzymes is needed to comprehend the mechanisms that contribute to specificity of pheromone signals. Most heliothine moths use sex pheromones with (Z)–11–hexadecenal as the major component in combination with minor fatty aldehydes and alcohols. In this study we focus on four closely related species, Heliothis virescens, Heliothis subflexa, Helicoverpa armigera and Helicoverpa assulta, which use (Z)–11–hexadecenal, (Z)–9–tetradecanal, and (Z)–9–hexadecenal in different ratios in their pheromone blend. The components are produced from saturated fatty acid precursors by desaturation, b–oxidation, reduction and oxidation. Results: We analyzed the composition of fatty acyl pheromone precursors and correlated it to the pheromone composition. Next, we investigated whether the downstream fatty–acyl reduction step modulates the ratio of alcohol intermediates before the final oxidation step. By isolating and functionally characterizing the Fatty Acyl Reductase (pgFAR) from each species we found that the pgFARs were active on a broad set of C8 to C16 fatty acyl substrates including the key pheromone precursors, Z9–14, Z9–16 and Z11–16:acyls. When presenting the three precursors in equal ratios to yeast cultures expressing any of the four pgFARs, all reduced (Z)–9–tetradecenoate preferentially over (Z)–11–hexadecenoate, and the latter over (Z)–9–hexadecenoate. Finally, when manipulating the precursor ratios in vitro, we found that the pgFARs display small differences in the biochemical activity on various substrates. Conclusions: We conclude that a pgFAR with broad specificity is involved in heliothine moth pheromone biosynthesis, functioning as a semi–selective funnel that produces species–specific alcohol product ratios depending on the fatty–acyl precursor ratio in the pheromone gland. This study further supports the key role of these in pheromone biosynthesis and emphasizes the interplay between the pheromone fatty acyl precursors and the Lepidoptera specific pgFARs in shaping the pheromone composition.
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| 8. |
- Heikkila, Katriina, et al.
(författare)
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Job Strain and Alcohol Intake : A Collaborative Meta-Analysis of Individual-Participant Data from 140 000 Men and Women
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7, s. Art. no. e40101-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The relationship between work-related stress and alcohol intake is uncertain. In order to add to the thus far inconsistent evidence from relatively small studies, we conducted individual-participant meta-analyses of the association between work-related stress (operationalised as self-reported job strain) and alcohol intake. Methodology and Principal Findings: We analysed cross-sectional data from 12 European studies (n = 142 140) and longitudinal data from four studies (n = 48 646). Job strain and alcohol intake were self-reported. Job strain was analysed as a binary variable (strain vs. no strain). Alcohol intake was harmonised into the following categories: none, moderate (women: 1-14, men: 1-21 drinks/week), intermediate (women: 15-20, men: 22-27 drinks/week) and heavy (women: > 20, men: > 27 drinks/week). Cross-sectional associations were modelled using logistic regression and the results pooled in random effects meta-analyses. Longitudinal associations were examined using mixed effects logistic and modified Poisson regression. Compared to moderate drinkers, non-drinkers and (random effects odds ratio (OR): 1.10, 95% CI: 1.05, 1.14) and heavy drinkers (OR: 1.12, 95% CI: 1.00, 1.26) had higher odds of job strain. Intermediate drinkers, on the other hand, had lower odds of job strain (OR: 0.92, 95% CI: 0.86, 0.99). We found no clear evidence for longitudinal associations between job strain and alcohol intake. Conclusions: Our findings suggest that compared to moderate drinkers, non-drinkers and heavy drinkers are more likely and intermediate drinkers less likely to report work-related stress.
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| 9. |
- Heikkila, Katriina, et al.
(författare)
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Job strain and the risk of inflammatory bowel diseases : individual-participant meta-analysis of 95 000 men and women
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:2, s. e88711-
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: Many clinicians, patients and patient advocacy groups believe stress to have a causal role in inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis. However, this is not corroborated by clear epidemiological research evidence. We investigated the association between work-related stress and incident Crohn's disease and ulcerative colitis using individual-level data from 95 000 European adults. Methods: We conducted individual-participant data meta-analyses in a set of pooled data from 11 prospective European studies. All studies are a part of the IPD-Work Consortium. Work-related psychosocial stress was operationalised as job strain (a combination of high demands and low control at work) and was self-reported at baseline. Crohn's disease and ulcerative colitis were ascertained from national hospitalisation and drug reimbursement registers. The associations between job strain and inflammatory bowel disease outcomes were modelled using Cox proportional hazards regression. The study-specific results were combined in random effects meta-analyses. Results: Of the 95 379 participants who were free of inflammatory bowel disease at baseline, 111 men and women developed Crohn's disease and 414 developed ulcerative colitis during follow-up. Job strain at baseline was not associated with incident Crohn's disease (multivariable-adjusted random effects hazard ratio: 0.83, 95% confidence interval: 0.48, 1.43) or ulcerative colitis (hazard ratio: 1.06, 95% CI: 0.76, 1.48). There was negligible heterogeneity among the study-specific associations. Conclusions: Our findings suggest that job strain, an indicator of work-related stress, is not a major risk factor for Crohn's disease or ulcerative colitis.
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| 10. |
- Heikkila, Katriina, et al.
(författare)
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Job Strain and Tobacco Smoking : An Individual-Participant Data Meta-Analysis of 166 130 Adults in 15 European Studies
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tobacco smoking is a major contributor to the public health burden and healthcare costs worldwide, but the determinants of smoking behaviours are poorly understood. We conducted a large individual-participant meta-analysis to examine the extent to which work-related stress, operationalised as job strain, is associated with tobacco smoking in working adults. Methodology and Principal Findings: We analysed cross-sectional data from 15 European studies comprising 166 130 participants. Longitudinal data from six studies were used. Job strain and smoking were self-reported. Smoking was harmonised into three categories never, ex- and current. We modelled the cross-sectional associations using logistic regression and the results pooled in random effects meta-analyses. Mixed effects logistic regression was used to examine longitudinal associations. Of the 166 130 participants, 17% reported job strain, 42% were never smokers, 33% ex-smokers and 25% current smokers. In the analyses of the cross-sectional data, current smokers had higher odds of job strain than never-smokers (age, sex and socioeconomic position-adjusted odds ratio: 1.11, 95% confidence interval: 1.03, 1.18). Current smokers with job strain smoked, on average, three cigarettes per week more than current smokers without job strain. In the analyses of longitudinal data (1 to 9 years of follow-up), there was no clear evidence for longitudinal associations between job strain and taking up or quitting smoking. Conclusions: Our findings show that smokers are slightly more likely than non-smokers to report work-related stress. In addition, smokers who reported work stress smoked, on average, slightly more cigarettes than stress-free smokers.
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