The use of exoskeletons in the occupational context for primary, secondary, and tertiary prevention of work-related musculoskeletal complaints.

OCCUPATIONAL APPLICATIONS This guideline includes 20 recommendations and four key statements that achieved consensus or strong consensus regarding the application of exoskeletons in the workplace for the prevention of musculoskeletal complaints and diseases, the general use and implementation of exoskeletons, and recommendations for risk assessment. The guideline is intended for company physicians, occupational physicians, ergonomists, occupational safety specialists, and employers, and serves as information for all other actors in practical occupational safety. Due to the lack of evidence from the scientific literature, the recommendations and key statements are the result of expert discussions that were conducted at a consensus conference in accordance with the Regulations of the Association of the Scientific Medical Societies in Germany, moderated by an external consultant.

TECHNICAL ABSTRACT Background The prevention of work-related musculoskeletal complaints and diseases has high priority, considering the prevalence of musculoskeletal complaints and diseases and the associated high burden on health care systems, the economy, and the people affected. Purpose: This guideline provided recommendations for potential applications of exoskeletons in the workplace for the primary, secondary, and tertiary prevention of musculoskeletal complaints and diseases, general recommendations on the use and implementation of exoskeletons, and recommendations on risk assessment. Methods: A systematic literature search, a survey among exoskeleton manufacturers and companies using exoskeletons, and expert discussions formed the basis of the formulated recommendations and key statements. For reaching consensus on the recommendations and key statements, we applied the Nominal Group and Delphi Techniques under the supervision of an external, independent moderator. Results: We formulated 20 recommendations and four key statements, all of which reached consensus or strong consensus. Conclusion: No answers could be found in the current scientific literature to the central questions in this guideline about primary, secondary, and tertiary prevention. We outline five main directions for future research on exoskeletons in occupational settings. First, using exoskeletons for prevention should be investigated using randomized controlled trials. Second, the effects of exoskeletons on work-related musculoskeletal stress and strain should be investigated both in the body region intended to be supported by the exoskeleton as well as in other non-supported body regions. Third, the effects of exoskeletons should be investigated in samples varying in age, gender, and health status, as well as during different occupational activities. Fourth, a specific risk assessment tool for exoskeletons in occupational settings should be developed and implemented to meet and evaluate the applicable occupational health and safety standards. Fifth, there is a need to expand upon the very limited social science research on the impacts of exoskeletons on employee professional understanding, social role understanding, or diversity.

Snap-fit assembly and upper limb functional limitations in automotive production workers: a nested case-control study.

OBJECTIVES: The use of snap-fits in car-part assembling has developed into an industrial standard. Cross-sectional evidence indicates, however, that this assembling process might adversely affect workers' upper limb function. The objective of this study was to analyze incident cases of upper limb functional limitations (ULFL) in relation to exposure to snap-fit assembly. METHODS: We performed a nested case-control study within a population of 5139 blue-collar automotive production workers. Cases with ULFL detected during follow-up were matched with controls based on employment duration and investigated on their exposure to snap-fit assembly. By conditional logistic regression, we modeled the risk for ULFL according to person-years of exposure to snap-fit assembly, adjusted for gender and baseline BMI. RESULTS: Overall, 64 ULFL cases were detected during a follow-up of 20610.8 person-years (3.1 cases per 1000 person-years). Cases, matched with an average of 4 controls, had significantly longer exposure duration to snap-fit assembly compared with controls (M = 1.15 person-years, SD = 1.68 person-years vs. M = 0.41 person-years, SD = 1.25 person-years). One person-year of exposure to snap-fit assembly was associated with an approximate 20% risk increase of developing ULFLs (OR 1.23, 95% CI 1.08-1.39). CONCLUSIONS: We confirm an association between accumulated exposure to snap-fits in car-part assembling and upper limb musculoskeletal disorders. Company physicians should thus be vigilant to symptoms of musculoskeletal disorders of the upper limbs in snap-fit assembly and support the development of threshold values for snap-fit insertion forces.

Entrepreneurship, Information, and Growth.

We examine the contribution to economic growth of entrepreneurial "marketplace information" within a regional endogenous growth framework. Entrepreneurs are posited to provide an input to economic growth through the information revealed by their successes and failures. We empirically identify this information source with the regional variation in establishment births and deaths, which create geographic information asymmetries that influence subsequent entrepreneurial activity and economic growth. We find that local establishment birth and death rates are significantly and positively correlated with subsequent entrepreneurship for US counties. To account for the potential endogeneity caused by forward-looking entrepreneurs, we utilize instruments based on historic mining activity. We find that the information spillover component of local establishment birth and death rates have significant positive effects on subsequent entrepreneurship and employment growth for US counties and metropolitan areas. With the help of these intruments, we show that establishment births have a positive and significant effect on future employment growth within all counties, and that in line with the information hypothesis, local establishment death rates have a similar positive effect within metropolitan counties.

Maternal exposure to hurricane destruction and fetal mortality.

BACKGROUND: The majority of research documenting the public health impacts of natural disasters focuses on the well-being of adults and their living children. Negative effects may also occur in the unborn, exposed to disaster stressors when critical organ systems are developing and when the consequences of exposure are large. METHODS: We exploit spatial and temporal variation in hurricane behaviour as a quasi-experimental design to assess whether fetal death is dose-responsive in the extent of hurricane damage. Data on births and fetal deaths are merged with Parish-level housing wreckage data. Fetal outcomes are regressed on housing wreckage adjusting for the maternal, fetal, placental and other risk factors. The average causal effect of maternal exposure to hurricane destruction is captured by difference-in-differences analyses. RESULTS: The adjusted odds of fetal death are 1.40 (1.07-1.83) and 2.37 (1.684-3.327) times higher in parishes suffering 10-50% and >50% wreckage to housing stock, respectively. For every 1% increase in the destruction of housing stock, we observe a 1.7% (1.1-2.4%) increase in fetal death. Of the 410 officially recorded fetal deaths in these parishes, between 117 and 205 may be attributable to hurricane destruction and postdisaster disorder. The estimated fetal death toll is 17.4-30.6% of the human death toll. CONCLUSIONS: The destruction caused by Hurricanes Katrina and Rita imposed significant measurable losses in terms of fetal death. Postdisaster migratory dynamics suggest that the reported effects of maternal exposure to hurricane destruction on fetal death may be conservative.

A quasi-experimental analysis of maternal altitude exposure and infant birth weight.

OBJECTIVES: We analyzed singleton births to determine the relationship between birth weight and altitude exposure. METHODS: We analyzed 715,213 singleton births across 74 counties from the western states of Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, and Washington from January 1, 2000, to December 31, 2000. Birth data were obtained from the Division of Vital Statistics, National Center for Health Statistics, for registered births. RESULTS: Regression analyses supported previous research by showing that a 1000-meter increase in maternal altitude exposure in pregnancy was associated with a 75.9-gram reduction in birth weight (95% confidence interval = -84.1, -67.6). Quantile regression models indicated significant and near-uniform depressant effects from altitude exposure across the conditional distribution of birth weight. Bivariate sample-selection models showed that a 1000-meter increase in altitude exposure, over and above baseline residential altitude, decreased birth weight by an additional 58.8 grams (95% confidence interval = -98.4, -19.2). CONCLUSIONS: Because of calculable health care-related costs associated with lower birth weight, our reported results might be of interest to clinicians practicing at higher altitudes.

Predictors for half-year outcome of impairment in daily life for back pain patients referred for physiotherapy: a prospective observational study.

BACKGROUND AND OBJECTIVE: From observational studies, there is only sparse information available on the predictors of development of impairment in daily life for patients receiving physiotherapy. Therefore, our aim was to identify factors which predict impairment in daily life for patients with back pain 6 months after receiving physiotherapy. METHODS: We conducted a prospective cohort study with 6-month follow-up. Patients were enrolled for treatment in private physiotherapy practices. Patients with a first physiotherapy referral because of thoracic or low back pain, aged 18 to 65 years were included. Primary outcome impairment was measured utilising the 16-item version of the Musculoskeletal Function Assessment Questionnaire. Therapy was documented on a standardized form. Baseline scores for impairment in daily life, symptom characteristics, sociodemographic and psychosocial factors, physical activity, nicotine consumption, intake of analgesics, comorbidity and delivered primary therapy approach were investigated as possible predictors. Univariate and multiple linear regression analyses were performed. RESULTS: A total of 792 patients participated in the study (59% female, mean age 44.4 (SD 11.4), with 6-month follow-up results available from 391 patients. In univariate analysis 17 variables reached significance. In multiple linear regression identified predictors were: impairment in daily life before therapy, mental disorders, duration of the complaints, self-prognosis on work ability, rheumatoid arthritis, age, form of stress at work and physical activity. The variables explain 34% of variance (adjusted R(2), p<0.001). CONCLUSIONS: With minimal information available from observational studies on the predictors of development of back problems for physiotherapy patients, this study adds new knowledge for forming appropriate referral guidelines. Impairment in daily life before therapy, mental disorder as comorbidity and the duration of the complaints can be named as outstanding factors. The results of this study can be used to facilitate comparison of patient therapy goals with the prognosis in everyday practice.

Daily variation in natural disaster casualties: information flows, safety, and opportunity costs in tornado versus hurricane strikes.

Casualties from natural disasters may depend on the day of the week they strike. With data from the Spatial Hazard Events and Losses Database for the United States (SHELDUS), daily variation in hurricane and tornado casualties from 5,043 tornado and 2,455 hurricane time/place events is analyzed. Hurricane forecasts provide at-risk populations with considerable lead time. Such lead time allows strategic behavior in choosing protective measures under hurricane threat; opportunity costs in terms of lost income are higher during weekdays than during weekends. On the other hand, the lead time provided by tornadoes is near zero; hence tornados generate no opportunity costs. Tornado casualties are related to risk information flows, which are higher during workdays than during leisure periods, and are related to sheltering-in-place opportunities, which are better in permanent buildings like businesses and schools. Consistent with theoretical expectations, random effects negative binomial regression results indicate that tornado events occurring on the workdays of Monday through Thursday are significantly less lethal than tornados that occur on weekends. In direct contrast, and also consistent with theory, the expected count of hurricane casualties increases significantly with weekday occurrences. The policy implications of observed daily variation in tornado and hurricane events are considered.

Associations between standardized school performance tests and mixtures of Pb, Zn, Cd, Ni, Mn, Cu, Cr, Co, and V in community soils of New Orleans.

In New Orleans a strong inverse association was previously identified between community soil lead and 4th grade school performance. This study extends the association to zinc, cadmium, nickel, manganese, copper, chromium, cobalt, and vanadium in community soil and their comparative effects on 4th grade school performance. Adjusting for poverty, food security, racial composition, and teacher-student ratios, regression results show that soil metals variously reduce and compress student scores. Soil metals account for 22%-24% while food insecurity accounts for 29%-37% of variation in school performance. The impact on grade point averages were Ni > Co > Mn > Cu ~ Cr ~ Cd > Zn > Pb, but metals are mixtures in soils. The quantities of soil metal mixtures vary widely across the city with the largest totals in the inner city and smallest totals in the outer city. School grade point averages are lowest where the soil metal mixtures and food insecurity are highest.

Maternal benzene exposure and low birth weight risk in the United States: a natural experiment in gasoline reformulation.

We investigate the relationship between maternal exposure to benzene and birth weight outcomes for resident births in the United States in 1996 and 1999, taking advantage of a natural experiment afforded by the regulation of benzene content of gasoline in various American cities. Regression results show that a unit increase (µg/m(3)) in maternal exposure to benzene reduces birth weight by 16.5 g (95% CI, 17.6 to 15.4). A unit increase in benzene exposure increases the odds of a low birth weight event by 7%. Similarly, a 1 µg/m(3) increase in benzene concentration increases the odds of very low birth weight event by a multiplicative factor of 1.23 (95% CI, 1.19 to 1.28). Difference-in-differences analyses show that birth weight increased by 13.7 g (95% CI, 10.7 to 16.8) and the risk of low birth weight decreased by a factor of .95 (95% CI, .93 to .98) in counties experiencing a 25% decline in benzene concentrations from 1996 to 1999. Public health policy and economic implications of results are discussed.

Economics of disaster risk, social vulnerability, and mental health resilience.

We investigate the relationship between exposure to Hurricanes Katrina and/or Rita and mental health resilience by vulnerability status, with particular focus on the mental health outcomes of single mothers versus the general public. We advance a measurable notion of mental health resilience to disaster events. We also calculate the economic costs of poor mental health days added by natural disaster exposure. Negative binomial analyses show that hurricane exposure increases the expected count of poor mental health days for all persons by 18.7% (95% confidence interval [CI], 7.44-31.14%), and by 71.88% (95% CI, 39.48-211.82%) for single females with children. Monthly time-series show that single mothers have lower event resilience, experiencing higher added mental stress. Results also show that the count of poor mental health days is sensitive to hurricane intensity, increasing by a factor of 1.06 (95% CI, 1.02-1.10) for every billion (U.S.$) dollars of damage added for all exposed persons, and by a factor of 1.08 (95% CI, 1.03-1.14) for single mothers. We estimate that single mothers, as a group, suffered over $130 million in productivity loss from added postdisaster stress and disability. Results illustrate the measurability of mental health resilience as a two-dimensional concept of resistance capacity and recovery time. Overall, we show that natural disasters regressively tax disadvantaged population strata.

Nonlinear associations between blood lead in children, age of child, and quantity of soil lead in metropolitan New Orleans.

Previous studies identified a curvilinear association between aggregated blood lead (BL) and soil lead (SL) data in New Orleans census tracts. In this study we investigate the relationships between SL (mg/kg), age of child, and BL (µg/dL) of 55,551 children in 280 census tracts in metropolitan New Orleans, 2000 to 2005. Analyses include random effects regression models predicting BL levels of children (µg/dL) and random effects logistic regression models predicting the odds of BL in children exceeding 15, 10, 7, 5, and 3 µg/dL as a function of age and SL exposure. Economic benefits of SL reduction scenarios are estimated. A unit raise in median SL°·5 significantly increases the BL level in children (b=0.214 p= or <0.01), and a unit change in Age°·5 significantly increases child BL (b=0.401, p= or <0.01). A unit change in Age°·5 increases the odds of a child BL exceeding 10 µg/dL by a multiplicative factor of 1.23 (95% CI 1.21 to 1.25), and a unit (mg/kg) addition of SL increases the odds of child BL> 10 µg/dL by a factor of 1.13 (95% CI 1.12 to 1.14). Extrapolating from regression results, we find that a shift in SL regulatory standard from 400 to 100 mg/kg provides each child with an economic benefit ranging from $4710 to $12,624 ($US 2000). Children's BL is a curvilinear function of both age and level of exposure to neighborhood SL. Therefore, a change in SL regulatory standard from 400 to 100mg/kg provides children with substantial economic benefit.

Maternal hurricane exposure and fetal distress risk.

Logistic regression and spatial analytic techniques are used to model fetal distress risk as a function of maternal exposure to Hurricane Andrew. First, monthly time series compare the proportion of infants born distressed in hurricane affected and unaffected areas. Second, resident births are analyzed in Miami-Dade and Broward counties, before, during, and after Hurricane Andrew. Third, resident births are analyzed in all Florida locales with 100,000 or more persons, comparing exposed and unexposed gravid females. Fourth, resident births are analyzed along Hurricane Andrew's path from southern Florida to northeast Mississippi. Results show that fetal distress risk increases significantly with maternal exposure to Hurricane Andrew in second and third trimesters, adjusting for known risk factors. Distress risk also correlates with the destructive path of Hurricane Andrew, with higher incidences of fetal distress found in areas of highest exposure intensity. Hurricane exposed African-American mothers were more likely to birth distressed infants. The policy implications of in utero costs of natural disaster exposure are discussed.

The impact of shift work induced chronic circadian disruption on IL-6 and TNF-alpha immune responses.

AIM: Sleep disturbances induce proinflammatory immune responses, which might increase cardiovascular disease risk. So far the effects of acute sleep deprivation and chronic sleep illnesses on the immune system have been investigated. The particular impact of shift work induced chronic circadian disruption on specific immune responses has not been addressed so far. METHODS: Pittsburgh-Sleep-Quality-Index (PSQI) questionnaire and blood sampling was performed by 225 shift workers and 137 daytime workers. As possible markers the proinflammatory cytokines IL-6 and TNF-alpha and lymphocyte cell count were investigated. A medical examination was performed and biometrical data including age, gender, height, weight, waist and hip circumference and smoking habits were collected by a structured interview. RESULTS: Shift workers had a significantly higher mean PSQI score than day workers (6.73 vs. 4.66; p < 0.001). Day workers and shift workers had similar serum levels of IL-6 (2.30 vs. 2.67 resp.; p = 0.276), TNF-alpha (5.58 vs. 5.68, resp.; p = 0.841) or lymphocytes count (33.68 vs. 32.99, resp.; p = 0.404). Furthermore there were no differences in cytokine levels (IL-6 p = 0.761; TNF-alpha p = 0.759) or lymphocyte count (p = 0.593) comparing the sleep quality within the cohorts. When this calculation of sleep quality was stratified by shift and day workers irrespective of their sleep quality day workers and shift workers had similar serum levels of IL-6, TNF-alpha or lymphocytes count. Multiple linear regression analysis showed a significant correlation of lymphocytes count and smoking habits. CONCLUSION: Shift work induces chronic sleep debt. Our data reveals that chronic sleep debt might not always lead to an activation of the immune system, as we did not observe differences in lymphocyte count or level of IL-6 or TNF-alpha serum concentration between shift workers and day workers. Therefore chronic sleep restriction might be eased by a long-term compensating immune regulation which (in healthy) protects against an overstimulation of proinflammatory immune mechanisms and moderates metabolic changes, as they are known from short-term sleep deprivation or sleep related breathing disorders.

New Orleans before and after Hurricanes Katrina/Rita: a quasi-experiment of the association between soil lead and children's blood lead.

Prior to Hurricanes Katrina and Rita (HKR), significant associations were noted between soil lead (SL) and blood lead (BL) in New Orleans. Engineering failure of New Orleans levees and canal walls after HKR set the stage for a quasi-experiment to evaluate BL responses by 13 306 children to reductions in SL. High density soil surveying conducted in 46 census tracts before HKR was repeated after the flood. Paired t test results show that SL decreased from 328.54 to 203.33 mg/kg post-HKR (t = 3.296, p < or = 0.01). Decreases in SL are associated with declines in children's BL response (r = 0.308, p < or = 0.05). When SL decreased at least 1%, median children's BL declined 1.55 microg/dL. Declines in median BL are largest in census tracts with > or =50% decrease in SL. Also individual BL in children was predicted as a function of SL, adjusting for age, year of observation, and depth of flood waters. At the individual scale, BL decreased significantly in post-HKR as a function of SL, with BL decreases ranging from b = -1.20 to -1.65 microg/dL, depending on the decline of SL and whether children were born in the post-HKR period. Our results support policy to improve soil conditions for children.

Correlates shift work with increased risk of gastrointestinal complaints or frequency of gastritis or peptic ulcer in H. pylori-infected shift workers?

AIM: There is an ongoing discussion whether work under shift work conditions enhances the ulcerogenic potential of Helicobacter pylori infections. This may be induced by a disruption of the circadian rhythm. The present study assessed whether there is an association between H. pylori infection and an increased risk of gastrointestinal complaints or frequency of gastritis or peptic ulcer in H. pylori-infected shift workers. METHODS: We analyzed 615 workers divided in shift and daytime. Upper gastrointestinal diseases, medication or operation, unspecific gastrointestinal complaints, smoking habits, subjective job strain and private stress factors were monitored. The H. pylori status was analyzed using IgA and IgG antibody concentration in blood and qualitative ELISA for feces. RESULTS: It was observed that 27.6% of all workers, 34.6% of the shift workers and 16% of daytime workers were Hp positive (P = 0.004). Shift workers reported reflux or pyrosis less frequently than daytime workers. No increased lifetime prevalence for gastritis, ulcus or eradication therapy was found for shift workers. Analysis revealed a weak regression between age and Hp-positive gastritis or upper gastrointestinal complaints, smoking habits were a major confounding factor for ulcus disease. Clinical manifestation of gastritis or ulcus disease did not correlate with shift work or especially shift work including night work. CONCLUSIONS: As a result of the present study, it cannot be confirmed that there is a causal connection between shift work and upper or unspecific gastrointestinal complaints or gastritis or peptic ulcer in dependency of a H. pylori colonization.

Outpatient rehabilitation of workers with musculoskeletal disorders using structured workplace description.

OBJECTIVES: In most industrialized countries musculoskeletal disorders contribute considerably (25%) to illness induced work absence. A special interest to reduce worker absences exists in highly specialized industries such as jet manufacturing, where specific knowledge is hard to replace. We investigated the reduction and sustainability in sick leave days by a workplace oriented outpatient rehabilitation program based on structured information exchange between occupational physicians and therapists. METHODS: Sick leave days reduction and return-to-work-ratios were analysed for 79 male blue collar workers with musculoskeletal disease, who voluntarily participated in an outpatient rehabilitation treatment between 2002 and 2005. During rehabilitation therapy standardized workplace descriptions were given to the therapists and individual return-to-work (rtw) schemes were implemented. Therapy lasted from 3 to 4 weeks followed by workplace reintegration. Off-work-time was calculated from 0 to 6 years before and 0 to 3 years after rehabilitation from insurance and industrial medical reports. RESULTS: A total of 97% of the patients returned to their original job at the workplace, usually directly after the rehabilitation. Average sick leave days per year were reduced from 48.8 +/- 32.8 days before to 34.2 +/- 37.3 days after the rehabilitation. The therapy interrupted an increase in sick leave days over the years stabilizing absence at a low level for at least 2 years. Duration of illness related work absence was the only significant predictor for sick leave reduction (P < 0.05). Other common risk factors for musculoskeletal diseases like smoking or body mass index did not significantly influence the therapeutic effect. CONCLUSIONS: Our results support evidence that information exchange for workplace description and rehabilitation therapist may help to reduce sick leave days and achieve very high rtw-ratio. However it is important to observe the effects of this shared information for longer intervals.