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Background Neighbourhood socioeconomic status (SES) has been shown to be related to health status and overweight independent of individual SES. However, results about the association between neighbourhood SES and physical activity among children are ambiguous. Particularly, it is unknown how socioeconomic factors influence the spatial context of children’s moderate-vigorous physical activity (MVPA) and sedentary behaviour (SB). This study aimed to investigate by means of Global Positioning System (GPS) and accelerometry whether locations where children engage in MVPA and SB differ by neighbourhood SES. Methods Participants included 83 children aged 7–9 from nine public schools located in a low- and high-SES area in Zurich, Switzerland. Children wore an accelerometer and GPS sensor for seven consecutive days. Time-matched accelerometer and GPS data was mapped with a geographic information system and each data point assigned to one of eight activity settings. The amount and proportion of MVPA and SB were calculated for every setting. To investigate differences between the two SES groups, multilevel analyses accounting for the hierarchical structure of the data were conducted. Results Both SES groups achieved most minutes in MVPA at own school, on streets and at home and recorded the highest proportions of MVPA in recreational facilities, streets and other schools. The highest amounts and proportions of SB were found at home and own school. High-SES children accumulated significantly more minutes in MVPA and SB in parks, sport facilities, other schools and streets, while the low-SES group spent more time in both activities in other places. When taking the total time spent in a setting into account and using the proportion of MVPA or SB, the only differences between the two groups were found at other schools and outside, where the high-SES children showed a significantly higher activity level (p-values, BMC Public Health, 16, ISSN:1471-2458

STROBE Statement. Checklist of items that should be included in reports of cross-sectional studies. (PDF 107 kb)

Multilevel analysis. Statistical models for the four outcome variables. (PDF 71 kb)

In the present study we aimed to track the influence of natural gaze behaviour on postural control from early childhood into adulthood. We measured time series of centre of pressure (COP) as well as head movement in three children groups aged around five (n = 16), eight (n = 15), and eleven (n = 14) and in one group of young adults (n = 15) during quiet stance with eyes closed, gaze fixed on a dot, and with gaze shifts between two dots. We adopted magnitude and irregularity of COP displacement as indexes of postural control and cross correlation between COP displacement and target oscillation as an index of the dynamical coupling between the postural and visual systems. Magnitude and irregularity of COP displacement decreased with age, which suggests a steady improvement of postural control from five to beyond eleven years of age. Cross correlations were weak and relative phases highly variable across age groups. Across conditions, and most prominently in the gaze shift conditions, 5-year-olds showed both more head movement and lower postural stability than other age groups. Finally, only in 5-year-olds did we find a marked deterioration of postural stability with gaze shifts. We thus conclude that excessive head movement, particularly during gaze shifts, may be a primary cause of lower postural stability in young children compared to older children and adults.

Background Several types of cognitive or combined cognitive-motor intervention types that might influence physical functions have been proposed in the past: training of dual-tasking abilities, and improving cognitive function through behavioral interventions or the use of computer games. The objective of this systematic review was to examine the literature regarding the use of cognitive and cognitive-motor interventions to improve physical functioning in older adults or people with neurological impairments that are similar to cognitive impairments seen in aging. The aim was to identify potentially promising methods that might be used in future intervention type studies for older adults. Methods A systematic search was conducted for the Medline/Premedline, PsycINFO, CINAHL and EMBASE databases. The search was focused on older adults over the age of 65. To increase the number of articles for review, we also included those discussing adult patients with neurological impairments due to trauma, as these cognitive impairments are similar to those seen in the aging population. The search was restricted to English, German and French language literature without any limitation of publication date or restriction by study design. Cognitive or cognitive-motor interventions were defined as dual-tasking, virtual reality exercise, cognitive exercise, or a combination of these. Results 28 articles met our inclusion criteria. Three articles used an isolated cognitive rehabilitation intervention, seven articles used a dual-task intervention and 19 applied a computerized intervention. There is evidence to suggest that cognitive or motor-cognitive methods positively affects physical functioning, such as postural control, walking abilities and general functions of the upper and lower extremities, respectively. The majority of the included studies resulted in improvements of the assessed functional outcome measures. Conclusions The current evidence on the effectiveness of cognitive or motor-cognitive interventions to improve physical functioning in older adults or people with neurological impairments is limited. The heterogeneity of the studies published so far does not allow defining the training methodology with the greatest effectiveness. This review nevertheless provides important foundational information in order to encourage further development of novel cognitive or cognitive-motor interventions, preferably with a randomized control design. Future research that aims to examine the relation between improvements in cognitive skills and the translation to better performance on selected physical tasks should explicitly take the relation between the cognitive and physical skills into account. ISSN:1471-2318

BACKGROUND Work injuries are a major problem worldwide. Approximately 360,000 fatal occupational injuries occur yearly, and more than 960,000 workers are injured daily. The worldwide estimated cost of work injuries is over US$ 400 billion a year. In Switzerland, the number of work injuries recognised by the Swiss National Accident Insurance Institution has remained stagnant at approximately 95 work injuries per 1,000 full-time employees annually, after a decrease in work injuries in the decade before. The stagnation of the decrease and the middle rank for work injury risk in the European comparison has resulted in a demand for revising prevention measures. A preliminary literature search on potentially important but disregarded causes of work injuries revealed that little is known about the personal factors influencing work injuries and that sleep problems may be a relevant but underestimated risk for work injury. Sleep problems are one of the most common health complaints with a varying prevalence of up to 40 % depending on the sleep problem type and examination method. Sleep problems may constrict the recovery function of sleep and lead to sleepiness during the day. Sleepiness may in turn reduce work performance and increase the risk of work injury. The role of sleep as a potential risk factor in injury prevention is still under debate. The strong belief and consensus among specialists that sleep problems have an impact on the incidence of work injuries has never been approached systematically and pooled quantitatively. No data from Switzerland are currently available on this topic. Furthermore, it is unclear whether sleep quality, sleep duration and daytime sleepiness influence the various types of work injuries differently. Additionally, limited and conflicting evidence is available on factors that modify the relationship between sleep problems and work injuries. OBJECTIVES Derived from the above knowledge gaps and research needs, the overall aims of this thesis were to (i) better understand the influence of sleep problems on work injuries, (ii) identify susceptible types of work injuries and populations most at risk and (iii) investigate whether our international findings can be verified for Switzerland. METHODS The research questions of this thesis were addressed in the framework of two separate study parts. First, a systematic literature review was performed consisting of a search of several databases. Original articles quantifying the relationship between sleep problems and work injuries were included up to July 7th, 2011. Pooled relative risks expressed in odds ratios (OR) and 95 % confidence intervals (CI) were calculated through random effects models. Several subgroup meta-analyses and meta-regression analyses were performed, and the population attributable risk was estimated. Second, a case-control study including 180 cases and 551 controls was conducted at the University Hospital of Basel, Switzerland, from December 1st 2009 to June 30th, 2011. Work injuries were defined according to Swiss law. Data on sleep problems were collected using the validated German versions of the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). The potential confounders considered included socioeconomic, health, lifestyle, occupational and environmental factors. Data analysis was performed in two steps; work injuries were investigated first, and then, we analysed the full case-control sample. RESULTS Through the systematic review, we identified 27 studies reporting 54 estimates for the relationship between sleep problems and work injuries. Meta-analysis suggested that sleep problems significantly increased the risk of suffering a work injury by 62 % (OR = 1.62, 95 % CI 1.43 – 1.84). Approximately 13 % of the work injuries were attributed to sleep problems. Subgroup meta-analysis showed that every type of sleep problem was significantly related to work injury; the highest risks were observed for taking sleep medication and breathing related sleep problems. Sleep problems tended to increase the work injury severity. Additionally, work injury risks tended to be higher in workers with more severe sleep problems. Findings from the case-control study suggested that workers with poor sleep quality had a 78 % (OR = 1.78, 95 % CI 1.01 – 3.17) higher risk of being injured at work than workers with good sleep quality. More severe sleep problems were associated with a higher work injury risk, and having sleep problems resulted in a greater history of work injuries, independent of case status. The analysis of the work injury data revealed that the work injury types most susceptible to sleep problems were falls and musculoskeletal injuries, injuries while working with or being injured by a tool or machine, and injuries while performing a side task. Sleep quality, sleep duration and daytime sleepiness were significant risk factors for at least one type of work injury. The populations identified as most at risk for sleep problem related work injuries were workers older than 30 years, sleeping 7 hours or less per night, and working 50 hours or more per week. CONCLUSIONS AND OUTLOOK This thesis adds further evidence that sleep problems are a considerable risk for work injuries. We not only systematically confirmed the suggested association between sleep problems and work injuries, we also quantitatively pooled the estimated risks for the first time. Furthermore, this thesis is the first comparison between international and Swiss results. Similar risks for sleep problem related work injuries were observed, and the international findings could therefore be verified for Switzerland. The socioeconomic burden of sleep problem related work injuries was estimated as considerable. Approximately CHF 290 million are spent on the consequences of sleep problem related work injuries in Switzerland every year. Up to every fifth work injury may be prevented if sleep problems are eliminated. The knowledge about the impact of sleep problems on work safety obliges responsible parties to take preventive action. This thesis adds valuable information on how to identify the risk of sleep problem related work injuries. The identification of the work injury types most susceptible to sleep problems may contribute to a better understanding of the injury causation and thus support a comprehensive recognition of injury causes. It may be useful to check workers involved in a fatigue related work incident for the sleep problems that are found to be associated with work injuries in this thesis to prevent them from similar events. Another approach may be to target sleep-related prevention measures to the population most at risk for sleep problem related work injuries identified in this thesis. Future studies on this topic should be conducted in basic research and applied science. Basic research in the field of sleep problem related work injuries needs to better characterise the mechanisms involved in the ways that sleep problems affect work injuries. For this purpose, laboratory simulations and epidemiological studies are needed. Furthermore, newly proposed analysis methods should be verified, and measures to assess which injury relevant aspects of sleep in the workplace setting need improvement. Applied science should be used to provide practical knowledge on how to protect workforces from sleep problem related work injuries. For a successful implementation of fatigue prevention measures, evidence-based information is needed along the causal chain of events potentially leading to an incident. To predict fatigue at the organisational and individual levels, behaviourally based methodologies need post-implementation research to define thresholds. The possibility for reducing the number of work injuries through sleep education needs to be evaluated for targeted injury prevention. Before launching a screening program for sleep problems, questions on feasibility or effectiveness need to be answered. Fatigue detection technologies and fatigue proofing systems need validation. Furthermore, occupational health and safety officers need to be trained in identifying fatigue-related factors that can cause injuries. In practice, many ideas on structural and behavioural strategies for work injury prevention exist. However, there are many unanswered questions about assessing fatigue management in the workplace. These questions need to be resolved before fatigue management systems can realise their full potential for contributing to injury prevention and helping to reduce the number of work injuries.