Screening for obstructive sleep apnea among hospital outpatients.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is common in adults. People with OSAS have a higher risk of experiencing traffic accidents and occupational injuries (OIs). We aimed to clarify the diagnostic performance of a three-channel screening device (ApneaLinkTM) compared with the gold standard of full-night attended polysomnography (PSG) among hospital outpatients not referred for sleep-related symptoms. Furthermore, we aimed to determine whether manual revision of the ApneaLinkTM autoscore enhanced diagnostic performance. METHODS: We investigated 68 patients with OI and 44 without OI recruited from the University Hospital Basel emergency room, using a cross-sectional study design. Participating patients spent one night at home with ApneaLinkTM and within 2 weeks slept for one night at the sleep laboratory. We reanalyzed all ApneaLinkTM data after manual revision. RESULTS: We identified significant correlations between the ApneaLinkTM apnea-hypopnea index (AHI) autoscore and the AHI derived by PSG (r = 0.525; p <0.001) and between the ApneaLinkTM oxygen desaturation index (ODI) autoscore and that derived by PSG (r = 0.722; p <0.001). The ApneaLinkTM autoscore showed a sensitivity and specificity of 82% when comparing AHI ≥5 with the cutoff for AHI and/or ODI ≥15 from PSG. In Bland Altman plots the mean difference between ApneaLinkTM AHI autoscore and PSG was 2.75 with SD ± 8.80 (ß = 0.034), and between ApneaLinkTM AHI revised score and PSG -1.50 with SD ± 9.28 (ß = 0.060). CONCLUSIONS: The ApneaLinkTM autoscore demonstrated good sensitivity and specificity compared with the gold standard (full-night attended PSG). However, Bland Altman plots revealed substantial fluctuations between PSG and ApneaLinkTM AHI autoscore respectively manually revised score. This spread for the AHI from a clinical perspective is large, and therefore the results have to be interpreted with caution. Furthermore, our findings suggest that there is no clinical benefit in manually revising the ApneaLinkTM autoscore.

Relationship between domain-specific physical activity and different body composition measures in a working population.

OBJECTIVE: With respect to the overweight epidemic, this study aimed to investigate the association between domain-specific physical activity and body composition measures in Swiss male employees. METHODS: A total of 192 healthy male adults in full-time employment were investigated. Height, weight, and waist circumference were measured and body mass index was calculated. Relative fat mass and relative muscle mass were determined by bioelectric impedance analysis. Physical activity was assessed by the validated International Physical Activity Questionnaire. RESULTS: In multiple linear regressions, leisure-time activity showed an inverse association with waist circumference and relative fat mass and a positive correlation with relative muscle mass. Work activity was positively related to waist circumference and body mass index. CONCLUSIONS: This study shows that leisure-time activity may be the most effective physical activity domain for body composition. Work activity does not seem to be protective against overweight.

Sleep quality and the risk of work injury: a Swiss case-control study.

Sleep problems are a well-known risk factor for work injuries, but less is known about which vulnerable populations are most at risk. The aims of this study were to investigate the association between sleep quality and the risk of work injury and to identify factors that may modify the association. A case-control study including 180 cases and 551 controls was conducted at the University Hospital in Basel, Switzerland, from 1 December 2009 to 30 June 2011. Data on work injuries and sleep quality were collected. Adjusted odds ratios and 95% confidence intervals of the association between sleep quality and work injury were estimated in multivariable logistic regression analyses and were stratified by hypothesized effect modifiers (age, gender, job risk, shift work, sleep duration and working hours). Poor sleep quality was associated significantly with work injury of any type (P < 0.05) and with being caught in particular (P < 0.05). The association between poor sleep quality and work injury was significantly higher for workers older than 30 years (odds ratio>30 1.30 versus odds ratio≤30 0.91, P < 0.01), sleeping 7 h or less per night (odds ratio≤7 1.17 versus odds ratio>7 0.79, P < 0.05) and working 50 h or more per week (odds ratio≥50 1.79 versus odd ratio<50 1.10, P < 0.01). Work injury risk increased with increasing severity of sleep problems (P < 0.05). Prior work injury frequency increased with decreasing sleep quality (P < 0.05). Older age, short sleep duration and long working hours may enhance the risk of work injuries associated with sleep quality.

Sleep problems and work injuries: a systematic review and meta-analysis.

OBJECTIVES: Sleep problems are a potential risk factor for work injuries but the extent of the risk is unclear. We conducted a systematic review and meta-analysis to quantify the effect of sleep problems on work injuries. METHODS: A systematic literature search using several databases was performed. Sleep problems of any duration or frequency as well as work injuries of any severity were of interest. The effect estimates of the individual studies were pooled and relative risks (RR) and 95% confidence intervals (CI) were calculated through random effects models. Additionally, the population attributable risk was estimated. RESULTS: In total, 27 observational studies (n = 268,332 participants) that provided 54 relative risk estimates were included. The findings of the meta-analysis suggested that workers with sleep problems had a 1.62 times higher risk of being injured than workers without sleep problems (RR: 1.62, 95% CI: 1.43-1.84). Approximately 13% of work injuries could be attributed to sleep problems. CONCLUSION: This systematic review confirmed the association between sleep problems and work injuries and, for the first time, quantified its magnitude. As sleep problems are of growing concern in the population, these findings are of interest for both sleep researchers and occupational physicians.

Sleep problems and work injury types: a study of 180 patients in a Swiss emergency department.

INTRODUCTION: Sleep problems present a risk for work injuries and are a major occupational health concern worldwide. Knowledge about the influence of sleep problems on work injury patterns is limited. Therefore, the aim of this study was to identify potential associations between different types of work injuries and sleep quality, sleep duration, and daytime sleepiness. METHODS: In this hospital-based study, 180 male and female patients with work injuries were recruited at the Emergency Department of the University Hospital Basel, Switzerland, from December 1st 2009 to June 30th 2011. The data on work injury characteristics, sleep problems, and potential confounders, such as demographic, health, lifestyle, occupational and environmental factors, were collected. Multivariable logistic regression analyses were performed to investigate the relationship between sleep problems and various types of work injury. RESULTS: Each dimension of sleep problems - sleep quality, sleep duration and daytime sleepiness - was a significant risk factor for at least one type of work injury. The strongest association was found for musculoskeletal injuries and falls with short sleep duration (odds ratio [OR] 5.41, 95% confidence interval [CI] 1.81-16.22). The standardised scores of the Pittsburgh sleep quality index (PSQI) and the Epworth sleepiness scale (ESS) did not discriminate between injury types. CONCLUSION: Employees with sleep problems were more likely to suffer from certain types of work injuries. This should be considered by employers monitoring work injuries and implementing prevention measures in the company's health and safety management.

Muscle fibre recruitment can respond to the mechanics of the muscle contraction.

This study investigates the motor unit recruitment patterns between and within muscles of the triceps surae during cycling on a stationary ergometer at a range of pedal speeds and resistances. Muscle activity was measured from the soleus (SOL), medial gastrocnemius (MG) and lateral gastrocnemius (LG) using surface electromyography (EMG) and quantified using wavelet and principal component analysis. Muscle fascicle strain rates were quantified using ultrasonography, and the muscle-tendon unit lengths were calculated from the segmental kinematics. The EMG intensities showed that the body uses the SOL relatively more for the higher-force, lower-velocity contractions than the MG and LG. The EMG spectra showed a shift to higher frequencies at faster muscle fascicle strain rates for MG: these shifts were independent of the level of muscle activity, the locomotor load and the muscle fascicle strain. These results indicated that a selective recruitment of the faster motor units occurred within the MG muscle in response to the increasing muscle fascicle strain rates. This preferential recruitment of the faster fibres for the faster tasks indicates that in some circumstances motor unit recruitment during locomotion can match the contractile properties of the muscle fibres to the mechanical demands of the contraction.