Marianne Schust

Traffic noise and risk of myocardial infarction.

Background: The biologic plausibility for noise stress-related cardiovascular responses is well established. Epidemiologic studies on the relationship between transportation noise and ischemic heart disease suggest a higher risk of myocardial infarction in subjects exposed to high levels of traffic noise. Methods: To determine the risk of road traffic noise for the incidence of myocardial infarction (MI), we carried out a hospital-based case-control study in the city of Berlin. We enrolled consecutive patients (n = 1881), age 20–69 years, with confirmed diagnosis of MI from 1998 through 2001. Controls (n = 2234) were matched according to sex, age, and hospital. Outdoor traffic noise level was determined for each study subject based on noise maps of the city. Standardized interviews were conducted to assess possible confounding factors and the annoyance from various noise sources. Results: The adjusted odds ratio for men exposed to sound levels of more than 70 dB(A) during the day was 1.3 (95% confidence interval = 0.88–1.8) compared with those where the sound level did not exceed 60 dB(A). In the subsample of men who lived for at least 10 years at their present address, the odds ratio was 1.8 (1.0–3.2). Noise-exposed women were not at higher risk. Conclusions: The results support the hypothesis that chronic exposure to high levels of traffic noise increases the risk for cardiovascular diseases.

A cohort study of sciatic pain and measures of internal spinal load in professional drivers

In a prospective cohort study of 537 male professional drivers, the occurrence of sciatic pain showed stronger associations with measures of internal lumbar load expressed in terms of daily compressive dose, Sed (MPa), and risk factor, R (non-dimensional), according to ISO/WD 2631-5 (2013), than with measures of daily vibration exposure calculated as either 8-h energy-equivalent frequency-weighted acceleration (ms− 2 r.m.s.) or vibration dose value (ms− 1.75) according to the EU Directive on mechanical vibration (2002). Herniated lumbar disc, previous lumbar trauma and physical work load were also powerful predictors of the occurrence of sciatic pain over time. Psychosocial work environment was poorly associated with sciatic pain. The boundary values of risk factor (R) for low and high probabilities of adverse health effects on the lumbar spine, as proposed by international standard ISO/WD 2631-5 (2013), tend to underestimate the health risk in professional drivers. Practitioner Summary: In a prospective cohort study of professional drivers, measures of internal spinal load were better predictors of the occurrence of sciatic pain than the measures of daily vibration exposure established by the EU Directive (2002). Herniated lumbar disc, lumbar trauma and physical work load were also associated with sciatic pain.

Timing of back muscles during whole-body vibration with transients : Its significance for the internal spinal load

To examine the response of back muscles to whole-body vibration (WBV) consisting of a sinusoidal “background” (4 Hz, r.m.s. acceleration 0.52 ms−2) and 10 interspersed periods with peak-to-peak amplitudes (“transients”) that varied in three steps (3.5, 7.2, and 11.1 ms−2), six surface electromyograms (EMGs) were obtained from different back muscles of 8 subjects at 3 different sitting postures (relaxed = R, bent forward = B and straight erect = E). The rectified undistorted EMGs and the force at the interface vibrator/subject of all subjects were averaged. The myoelectric activity at R was minimal, B and E were accompanied by a high basic EMG-activity and pronounced responses to the transients. The timing of the maximum EMG-responses varied. A nonlinear increase of the internal load was predicted with rising amplitudes of transients. The threshold for this prominent unfavourable biological effect might be located between 3.5 and 5 ms−2.

Lombalgia ed esposizione occupazionale a vibrazioni trasmesse al corpo intero e a shock meccanici: considerazioni sullo stato dell’arte

This paper offers an overview of the relation of low back pain (LBP) to occupational exposures to whole-body vibration (WBV) and mechanical shocks. LBP is a condition of multifactorial origin and is a very common health problem in the general population. Among occupational risk factors, epidemiological studies of driving occupations have provided evidence for strong associations between LBP and occupational exposures to WBV and mechanical shocks. Since it is hard to separate the contribution of WBV exposure to disorders in the lower back from that of other individual, ergonomic or psychosocial risk factors, a quantitative exposure-response relationship for WBV cannot be outlined precisely. Experimental research has provided biodynamic support to the findings of epidemiological studies, showing that in controlled laboratory conditions exposure to WBV can cause mechanical overload to the human spine. The EU Directive on mechanical vibration has established daily exposure action and limit values to protect the workers against the risk from WBV. There is some evidence that the EU exposure limit values are excessive, so much so that an elevated risk of LBP has been found for WBV exposures beneath the EU limit values. In the Italian arm of the EU VIBRISKS prospective cohort study of professional drivers, measures of internal lumbar load (compressive and shear peak forces), calculated by means of anatomy-based finite-element models, were found better predictors of the occurrence over time of low back disorders than the metrics of external exposure suggested by the EU Directive on mechanical vibration. Further biodynamic and epidemiological studies are needed to validate the findings of the VIBRISKS study.

Measures of internal lumbar load in professional drivers – the use of a whole-body finite-element model for the evaluation of adverse health effects of multi-axis vibration

The present study aimed to (1) employ the method for evaluation of vibration containing multiple shocks according to ISO/CD 2631–5:2014 (Model 1) and DIN SPEC 45697:2012 in a cohort of 537 professional drivers, (2) deliver the results for a re-analysis of epidemiological data obtained in the VIBRISKS study, (3) clarify the extent to which vibration acceleration and individual variables influence risk values, such as the daily compressive dose Sed and the risk factor R, and (4) compare the results with in vivo measurements and those obtained in previous studies with similar models. The risk factor R was influenced by the acceleration, lifetime exposure duration, sitting posture, age at the start of exposure and body mass/body mass index in order of decreasing effect. Age and annual and daily exposure duration had only a marginal effect. The daily compressive dose Sed and the risk factor R showed weak linear association with the daily vibration exposure A(8) and the vibration dose value VDV. The study revealed high shear forces in the lumbar spine. Practitioner Summary: In a re-analysis of an epidemiological study of professional drivers, a software tool available with standards DIN SPEC 45697:2012 and ISO/CD 2631–5:2014 Model 1 was used to calculate the risk to the lumbar spine in terms of daily compressive dose Sed and risk factor R. The tool was found to be suitable for risk assessment in a large cohort.

Validation of newly developed and redesigned key indicator methods for assessment of different working conditions with physical workloads based on mixed-methods design: a study protocol

Introduction The impact of work-related musculoskeletal disorders is considerable. The assessment of work tasks with physical workloads is crucial to estimate the work-related health risks of exposed employees. Three key indicator methods are available for risk assessment regarding manual lifting, holding and carrying of loads; manual pulling and pushing of loads; and manual handling operations. Three further KIMs for risk assessment regarding whole-body forces, awkward body postures and body movement have been developed de novo. In addition, the development of a newly drafted combined method for mixed exposures is planned. All methods will be validated regarding face validity, reliability, convergent validity, criterion validity and further aspects of utility under practical conditions. Methods and analysis As part of the joint project MEGAPHYS (multilevel risk assessment of physical workloads), a mixed-methods study is being designed for the validation of KIMs and conducted in companies of different sizes and branches in Germany. Workplaces are documented and analysed by observations, applying KIMs, interviews and assessment of environmental conditions. Furthermore, a survey among the employees at the respective workplaces takes place with standardised questionnaires, interviews and physical examinations. It is intended to include 1200 employees at 120 different workplaces. For analysis of the quality criteria, recommendations of the COSMIN checklist (COnsensus-based Standards for the selection of health Measurement INstruments) will be taken into account. Ethics and dissemination The study was planned and conducted in accordance with the German Medical Professional Code and the Declaration of Helsinki as well as the German Federal Data Protection Act. The design of the study was approved by ethics committees. We intend to publish the validated KIMs in 2018. Results will be published in peer-reviewed journals, presented at international meetings and disseminated to actual users for practical application.

1277 Newly developed and redesigned key indicator methods for assessment of different physical workloads – key elements of the validation study

Introduction The assessment of work tasks with physical workloads is crucial to estimate the work-related health risks of employees. Three key indicator methods (KIMs) are available for risk assessment regarding manual lifting, holding and carrying of loads, manual pulling and pushing, and manual handling operations. Three further KIMs regarding whole-body forces, awkward body postures and body movement have been developed de novo. The development of a combined method for mixed exposures is planned. All methods will be validated regarding face validity, reliability, convergent validity, criterion validity. Methods A mixed-methods study was designed for the validation of KIMs. The following working hypotheses (WH) are tested: WH 1: The KIMs reflect adequately the construct to be measured (face validity). WH 2: No relevant deviations occur between different users using KIMs and assessing the same workplaces (reliability). WH 3: Assessing workplaces using the KIMs and other screening methods will result in no relevant differences (convergent validity). WH 4: It is assumed that employees at workplaces with high KIM risk scores show adverse health related outcomes more frequently than non-exposed workers (criterion validity). With this background a field study was conducted in companies of different sizes and branches in Germany as part of the joint project MEGAPHYS (multilevel risk assessment of physical workloads). Ethics and dissemination: The study was planned and conducted in accordance with the Declaration of Helsinki, the design was approved by ethics committees. We intend to publish validated KIMs in 2018. Acknowledgements/funding: The (further) development and validation of the KIMs is part of project MEGAPHYS funded by BAuA and the German Social Accident Insurance (DGUV). Further MEGAPHYS partners are Institute for Occupational Safety and Health of DGUV (IFA), Institute of Ergonomics at the Darmstadt University of Technology (IAD) and Leibniz Research Centre for Working Environment and Human Factors (IfADo).

Perception of fore-and-aft whole-body vibration intensity measured by two methods

This experimental study investigated the perception of fore-and-aft whole-body vibration intensity using cross-modality matching (CM) and magnitude estimation (ME) methods. Thirteen subjects were seated on a rigid seat without a backrest and exposed to sinusoidal stimuli from 0.8 to 12.5 Hz and 0.4 to 1.6 ms− 2 r.m.s. The Stevens exponents did not significantly depend on vibration frequency or the measurement method. The ME frequency weightings depended significantly on vibration frequency, but the CM weightings did not. Using the CM and ME weightings would result in higher weighted exposures than those calculated using the ISO (2631-1, 1997) Wd. Compared with ISO Wk, the CM and ME-weighted exposures would be greater at 1.6 Hz and lesser above that frequency. The CM and ME frequency weightings based on the median ratings for the reference vibration condition did not differ significantly. The lack of a method effect for weightings and for Stevens exponents suggests that the findings from the two methods are comparable. Practitioner Summary: Frequency weighting curves for seated subjects for x-axis whole-body vibration were derived from an experiment using two different measurement methods and were compared with the Wd and Wk weighting curves in ISO 2631-1 (1997).

Combined effects of noise and whole body vibration in the working environment

The simultaneous exposure to noise and whole‐body vibration (WBV) is the most frequent combination of physical factors at workplaces. Both factors probably act not‐independently of each other. The results of the studies regarding the aural effects indicate that additional exposure to WBV amplifies the temporary threshold shift as well as of the permanent threshold shift. Various parameters, i.e., postural sway, vision, and cardiovascular changes, were investigated in experimental studies to clarify the extraaural physiological effects. The results demonstrate a dependence on the intensity and the frequency spectrum of the noise as well as of the WBV. Mutually amplifying interactions of noise and WBV were observed. The events of experimental research regarding the subjective assessment of exposure conditions suggest the following conclusions: an increase of noise intensity causes stronger sensations of the WBV intensity except for WBV with main frequencies around 2.5 Hz. Changes of WBV intensity have no ef...