Effectiveness of a worksite intervention to reduce an occupational exposure: the Minnesota wood dust study

A cluster randomised controlled trial to reduce respiratory effects of cotton dust exposure among textile workers: the MultiTex RCT study

BACKGROUND

We determined the effectiveness of an intervention to reduce cotton dust-related respiratory symptoms and improve lung function of textile workers.

METHODS

We undertook a cluster randomised controlled trial at 38 textile mills in Karachi, Pakistan. The intervention comprised: training in occupational health for workers and managers, formation of workplace committees to promote a health and safety plan that included wet mopping and safe disposal of cotton dust, provision of simple face masks, and further publicity about the risks from cotton dust. Participating mills were randomised following baseline data collection. The impact of the intervention was measured through surveys at 3, 12 and 18 months using questionnaires, spirometry and dust measurements. The primary outcomes were 1) changes in prevalence of a composite respiratory symptom variable, 2) changes in post-bronchodilator percentage predicted forced expiratory volume in 1 s (FEV1) and 3) changes in cotton dust levels. These were assessed using two-level mixed effects linear and logistic regression.

RESULTS

Of 2031 participants recruited at baseline, 807 (40%) were available at the third follow-up. At that point, workers in the intervention arm were more likely to report an improvement in respiratory symptoms (OR 1.58, 95% CI 1.06-2.36) and lung function (FEV1 % pred: β 1.31%, 95% CI 0.04-2.57%). Personal dust levels decreased, more so in intervention mills, although we did not observe this in adjusted models due to the small number of samples.

CONCLUSION

We found the intervention to be effective in improving the respiratory health of textile workers and recommend scaling-up of such simple and feasible interventions in low- and middle-income countries.

Wood Dust Exposure Levels and Respiratory Symptoms 6 Years Apart: An Observational Intervention Study Within the Danish Furniture Industry

OBJECTIVES

Occupational exposure to wood dust can cause respiratory diseases, but few studies have evaluated the impact of declining exposure on health outcome. This study aimed to investigate whether a decline in wood dust exposure between two cross sectional studies performed in 1997-1998 and 2003-2004 was related to the prevalences of respiratory symptoms among woodworkers in a well-defined geographical area.

METHODS

Two thousand and thirty-two woodworkers from 54 plants in study 1 and 1889 woodworkers from 52 plants in study 2 returned a questionnaire on respiratory diseases and symptoms, employment and smoking habits. Current individual wood dust exposure level was assessed from 2 study specific job exposure matrix's based on task, factory size and personal passive dust measurements (2217 in study 1 and 1355 in study 2).

RESULTS

The median (range) of inhalable dust was 1.0 mg/m3 (0.2-9.8), 0.6 mg/m3 (0.1-4.6) in study 1 and study 2, respectively. In study 2, the prevalence's of self-reported asthma was higher and the prevalence's of respiratory symptoms were lower compared to study 1. In adjusted logistic regression analyses using GEE methodology to account for clustering, dust exposure level could explain the differences in prevalence of coughing, chronic bronchitis and nasal symptoms between study 1 and study 2, while no effect was found for asthma.

CONCLUSIONS

A 40% decline in wood dust exposure in a 6 year period may serve as an explanation for the decline in most respiratory symptoms, but do not seems to impact the prevalence of self-reported asthma.

The effect of educational intervention on promoting safe behaviors in textile workers

Behavioral modification is an inseparable part of a comprehensive accident prevention strategy in a workplace. This study reports a behavior modification approach applied to evaluate the effectiveness of an occupational safety training educational intervention on industrial textile workers in Borujerd, Iran. This research is a quasi-experimental Solomon four-group design participatory study conducted as a pre-test and post-test intervention. Totally, 85 workers participated in the study. The study was developed through a participatory approach, exclusively for the present research. In fact, we applied a combination concept of the PRECEDE-PROCEED model and the theory of planned behavior in planning and implementing the educational interventions. The results revealed significant improvements among all four groups within 1 and 3 months post intervention. The percentage of unsafe practices declined dramatically when the program was implemented. In conclusion, the appropriately developed educational intervention program led to improved safety practices among workers in the present study.

Interventions to Reduce Exposures in the Workplace: A Systematic Review of Intervention Studies Over Six Decades, 1960-2019

Background: Reducing occupational ill-health from chemical and biological agents is realized primarily through the mitigation and elimination of hazardous exposures. Despite evidence of declining exposure in European and North-American workplaces, comprehensive studies of the effectiveness of workplace interventions for reducing hazardous exposure and associated work-related ill-health seem rare. We reviewed occupational intervention studies targeting exposure to chemical and biological agents, and determined trends in frequency and quality of such studies. Methods: We searched Embase, Medline, and Web of Science for peer-reviewed original articles on occupational intervention studies published 1960-2019, aimed at reducing workers' exposure to dusts, gases, fumes, or liquids of chemical, biological, or mineral nature, or workers' risks for associated health outcomes. The frequency of articles, intervention types, intervention endpoints, and study quality of published intervention studies between 1960 and 2019 and according to 10-year intervals were analyzed. Results: Of 3,663 retrieved articles, 146 intervention studies were identified and reviewed, of which 63 concerned control measures, 43 behavioral change, 28 use of personal protective equipment, and 12 workplace policies. Intervention endpoints were occupational exposures (73%), health outcomes (22%), and a combination of both (5%). Of reviewed studies, 38% involved a control group, 16% randomized the intervention, 86% were planned interventions, and 86% compared exposure or health outcomes pre and post intervention. Over time the number of intervention studies identified in this search increased from none during 1960-1969 to ~60 during 2000-2009 and 2010-2019, respectively. The study quality improved over time, with no studies during 1960-1989 that complied with the highest quality criteria. During 2000-2009 and 2010-2019 16 and 12% of studies, respectively, were judged to be of highest quality. Conclusion: Despite an improvement over the last six decades in the frequency and quality of intervention studies targeting exposure to chemicals and biological agents, the absolute number of intervention studies remains low, particularly when considering only high quality studies. Occupational exposure to chemical and biological agents is still causing excessive disease in workforces worldwide. To reduce occupational ill-health caused by these exposures, it is important to expand the evidence on (cost-)effectiveness and transferability of interventions to reduce exposure and health effects.

Findings From the National Machine Guarding Program: Safety Climate, Hazard Assessment, and Safety Leadership in Small Metal Fabrication Businesses

This manuscript assesses safety climate data from the National Machine Guarding Program (NMGP)—a nationwide intervention to improve machine safety.

Feedback on Measured Dust Concentrations Reduces Exposure Levels Among Farmers

BACKGROUND

The high burden of exposure to organic dust among livestock farmers warrants the establishment of effective preventive and exposure control strategies for these workers. The number of intervention studies exploring the effectiveness of exposure reduction strategies through the use of objective measurements has been limited.

OBJECTIVE

To examine whether dust exposure can be reduced by providing feedback to the farmers concerning measurements of the exposure to dust in their farm.

METHODS

The personal dust levels of farmers in 54 pig and 26 dairy cattle farms were evaluated in two measurement series performed approximately 6 months apart. Detailed information on work tasks and farm characteristics during the measurements were registered. Participating farms were randomized a priori to a control (n = 40) and an intervention group (n = 40). Shortly after the first visit, owners of intervention farms only received a letter with information on the measured dust concentrations in the farm together with some general advises on exposure reduction strategies (e.g. use of respirators during certain tasks). Relationships between measured dust concentrations and intervention status were quantified by means of linear mixed effect analysis with farm and worker id as random effects. Season, type of farming, and work tasks were treated as fixed effects. Changes in exposure over time were explored primarily at a farm level in models combined, as well as separate for pig and cattle farmers.

RESULTS

After adjustment for fixed effects, an overall reduction of 23% in personal dust exposures was estimated as a result of the intervention (P = 0.02). Exposure reductions attributable to the intervention were similar across pig and cattle farmers, but statistically significant only for pig farmers. Intervention effects among pig farmers did not depend on the individuals' information status; but among cattle farmers a significant 48% reduction in exposure was found only among individuals that reported to have been informed. No systematic differences in changes over time considering the use of respiratory protection between the intervention and control groups were observed.

CONCLUSION

The results of the present study suggest reductions between 20 and 30% in personal exposure to inhalable dust to be feasible through simple information provided to the farm owners regarding actual levels of exposure together with instructions on basic measures of prevention. The exact reasons for these effects are unclear, but likely they involve changes in behavior and working practices among intervention farmers.

Findings From the National Machine Guarding Program: A Small Business Intervention: Lockout/Tagout

OBJECTIVE

Failure to implement lockout/tagout (LOTO) procedures adversely affects the rate of work-related fatalities and serious traumatic injury and is one of the most frequently cited Occupational Safety and Health Administration standards. This study assesses the impact of a nationwide intervention to improve LOTO in small metal fabrication businesses.

METHODS

Insurance safety consultants conducted a standardized and validated evaluation of LOTO programs and procedures. Businesses received a baseline evaluation, two intervention visits, and a 12-month follow-up evaluation.

RESULTS

The intervention was completed by 160 businesses. The mean LOTO procedure score improved from 8% to 33% (P < 0.0001), the mean program score went from 55% to 76% (P < 0.0001), and the presence of lockable disconnects went from 88% to 92% (P < 0.0001).

CONCLUSIONS

This nationwide intervention showed substantial improvements in LOTO. It provides a framework for assessing and improving LOTO.

The Collision Auto Repair Safety Study (CARSS): a health and safety intervention

BACKGROUND

Collision repair employs approximately 205,500 people in 33,400 shops. Workers are exposed to a diverse array of chemical, physical, and ergonomic hazards.

METHODS

CARSS was based on a random and purposeful sample. Baseline and one baseline and one-year evaluations consisted of 92 questions addressing issues, such as Right-to-Know, fire protection, painting-related hazards, ergonomics, electrical safety, and personal protective equipment. Owners received a report and selected at least 30% of items found deficient for remediation. In-person and web-based services were provided.

RESULTS

Forty-nine shops were evaluated at baseline and 45 at follow-up. At baseline, 54% of items were present. This improved to 71% at follow-up (P < 0.0001). Respiratory protection improved 37% (P < 0.0001) and Right-to-Know training increased 30% (P < 0.0001). Owners completed 61% of items they selected for remediation.

CONCLUSIONS

Small businesses' interventions should address the lack of personnel and administrative infrastructure. Tailored information regarding hazards and easy-to-use training and administrative programs overcome many barriers to improvement.

Exposure to crystalline silica at Alberta work sites: review of controls

From 2009 to 2013, Alberta Jobs, Skills, Training, and Labour (JSTL) conducted a project to evaluate exposure to crystalline silica and assess controls to protect workers. Information on exposure results has been previously reported; this article discusses the data collected on workplace controls. Information on work site controls was collected during exposure assessments consisting of qualitative information on controls in place and used by workers at the time of the assessments. Where there was sufficient data, the information was further analyzed to evaluate the impact of a particular control. While many types of controls were observed, they were not always effective or in use. The control available most often was respiratory protective equipment (RPE). Generally, when respirators were used, they were correctly selected for the level of measured exposure. However, not all workers who were potentially overexposed wore respirators at the time of the assessments. When the use of respirators was taken into account, about one-third of workers were still potentially exposed over the Alberta occupational exposure limit. The industries with the highest levels of exposure tended to be those with the most unprotected workers. Issues were identified with the use of improper work practices such as dry cleaning methods, lack of documented work procedures, poor housekeeping, and lack of training which may have contributed to worker exposure levels. There is a wide range in the efficacy of controls, particularly engineering controls. Most of the literature focuses on engineering controls; however administrative controls also play a role in reducing worker exposure. Data collected in this work indicated that simple changes to work procedures and behavior (such as improved housekeeping) may be effective, low-cost ways to reduce workplace exposure. More study is required to evaluate the impact and efficacy of administrative controls such as housekeeping and training. Employers must select and evaluate controls in the context of overall workplace health and safety programs and ensure that they are supported by supervision, good work practices. and training.

'Relieved Working' study: systematic development and design of an intervention to decrease occupational quartz exposure at construction worksites

Background

Occupational quartz exposure continues to be a serious hazard in the construction industry. Until now, evidence-based interventions aimed at reducing quartz exposure are scarce. The aim of this study was to systematically develop an intervention and to describe the study to evaluate its effectiveness.

Methods/Design

The intervention was developed according to the principles of the Intervention Mapping protocol, meaning that evidence from the literature was combined with information collected from stakeholders (e.g., construction workers, managers and researchers). The intervention aimed to integrate technical, behavioural and organizational factors. The intervention consists of two plenary meetings for all employers within the company, and individual visits at construction worksites, including specific intervention materials. Additionally, a demonstration session regarding control measures was organized for all managers. The effectiveness of the intervention will be evaluated in a cluster randomized controlled trial among eight construction companies, with measurements at baseline and follow-up. Outcome measures are personal respirable dust and quartz exposure by means of exposure assessment, and behavioural and organizational determinants which will be assessed by means of questionnaires. Additionally, a process evaluation will shed light on whether the intervention (does not) works, and, if so, the reasons for this.

Discussion

Applying Intervention Mapping in the development of an intervention to reduce occupational quartz exposure was useful, as different stakeholders provided input for the intervention as well as the implementation strategy. Therefore, the feasibility of the intervention has been enhanced, as it appeals to construction workers and managers and will not unduly interfere with the ongoing construction work.

Trial registration number

NTR4586 (May 7th 2014).

Effectiveness of interventions to reduce flour dust exposures in supermarket bakeries in South Africa

RATIONALE

A recent study of supermarket bakery workers in South Africa demonstrated that 25% of workers were sensitised to flour allergens and 13% had baker's asthma. Evidence on exposure reduction strategies using specifically designed interventions aimed at reducing the risk of baker's asthma is scarce.

OBJECTIVES

The aim of this study was to evaluate the effectiveness of different control measures to reduce airborne flour dust exposure using a randomised design.

METHODS

A group-randomised study design was used to assign 30 bakeries of a large supermarket chain store to two intervention groups and a control group, of which 15 bakeries were studied. Full-shift environmental personal samples were used to characterise exposure to flour dust and wheat and rye allergens levels pre-intervention (n=176) and post-intervention (n=208).

RESULTS

The overall intervention effect revealed a 50% decrease in mean flour dust, wheat and rye allergen exposure. The reduction in exposure was highest for managers (67%) and bakers (47%), and lowest for counterhands (23%). For bakers, the greatest reduction in flour dust was associated with control measures such as the use of the mixer lid (67%), divider oil (63%) or focused training (54%). However, the greatest reduction (80%) was observed when using a combination of all control measures.

CONCLUSIONS

A specially designed intervention strategy reduced both flour dust and allergen levels. Best results were observed when combining both engineering controls and training. Further studies will investigate the long-term health impact of these interventions on reducing the disease burden among this group of bakers.

Essential Occupational Safety and Health Interventions for Low- and Middle-income Countries: An Overview of the Evidence

There is still a considerable burden of occupational diseases and injuries in the world. It is not well known which interventions can effectively reduce the exposures at work that cause this burden. The objective of this article is to summarize evidence from systematic reviews of interventions to prevent occupational diseases and injuries. We included systematic reviews of interventions to reduce the incidence of work-related cancer, dust-related diseases, occupational asthma, chronic obstructive pulmonary disease, noiseinduced hearing loss, back pain, and occupational injuries. We searched Medline and Embase with predefined search strategies to locate systematic reviews of these interventions. We found 23 systematic reviews of which the results are also applicable to low- and middle income countries. Effective measures to reduce exposure leading to work-related cancer, dust-related diseases, asthma, chronic obstructive pulmonary disease, noise, and injuries are available. However, better implementation of these measures is needed. Regulation, enforcement of regulation, and incentives for employers are effective interventions to achieve this goal. There is evidence that feedback and rewards for workers help in reducing occupational injuries. There is no evidence in many studies that back pain can be prevented. Personal protective equipment technically has the potential to reduce exposure but this is difficult to put into effect. There is no evidence in the studies regarding the effectiveness of education and training, preventive drugs, or health examinations. There is evidence that the implementation of technical measures enforced by regulation can prevent occupational diseases and injuries. For other interventions such as education or health examinations, there is no evidence that supports their effectiveness. More systematic reviews are needed in the area of injury prevention.

Characterization of wood dust from furniture by scanning electron microscopy and energy-dispersive x-ray analysis

Study characterized and analyzed form factor, elementary composition and particle size of wood dust, in order to understand its harmful health effects on carpenters in Quindío (Colombia). Once particle characteristics (size distributions, aerodynamic equivalent diameter (D(α)), elemental composition and shape factors) were analyzed, particles were then characterized via scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray analysis (EDXRA). SEM analysis of particulate matter showed: 1) cone-shaped particle ranged from 2.09 to 48.79 µm D(α); 2) rectangular prism-shaped particle from 2.47 to 72.9 µm D(α); 3) cylindrically-shaped particle from 2.5 to 48.79 µm D(α); and 4) spherically-shaped particle from 2.61 to 51.93 µm D(α). EDXRA reveals presence of chemical elements from paints and varnishes such as Ca, K, Na and Cr. SEM/EDXRA contributes in a significant manner to the morphological characterization of wood dust. It is obvious that the type of particles sampled is a complex function of shapes and sizes of particles. Thus, it is important to investigate the influence of particles characteristics, morphology, shapes and D(α) that may affect the health of carpenters in Quindío.

Effectiveness of health and safety in small enterprises: a systematic review of quantitative evaluations of interventions

INTRODUCTION

This systematic review was conducted to identify effective occupational health and safety interventions for small businesses.

METHODS

The review focused on peer-reviewed intervention studies conducted in small businesses with 100 or fewer employees, that were published in English and several other languages, and that were not limited by publication date. Multidisciplinary members of the review team identified relevant articles and assessed their quality. Studies assessed as medium or high quality had data extracted, which was then synthesized.

RESULTS

Five studies were deemed of medium or high quality, and proceeded to data extraction and evidence synthesis. The types of interventions identified: a combination of training and safety audits; and a combination of engineering, training, safety audits, and a motivational component, showed a limited amount of evidence in improving safety outcomes. Overall, this evidence synthesis found a moderate level of evidence for intervention effectiveness, and found no evidence that any intervention had adverse effects.

CONCLUSIONS

Even though there were few studies that adequately evaluated small business intervention, several studies demonstrate that well-designed evaluations are possible with small businesses. While stronger levels of evidence are required to make recommendations, these interventions noted above were associated with positive changes in safety-related attitudes and beliefs and workplace parties should be aware of them.

Health and working conditions in carpenter's workshops in Armenia (Colombia)

We conducted a study of the health and working conditions in 10 carpenter's workshops in the municipality of Armenia (Colombia). In these workshops, all the most exposed workers to wood dust were surveyed at the areas of sanding, brushing, immunization and painting (workers with the highest risk to get chronic respiratory disease). They were 177 workers. The use of hard and soft woods for furniture was detected. Besides, some pesticides, volatile organic solvents, synthetic epoxy resins glues and paintings, were used for finishes, which increases the risk of acquiring some neurological diseases and damage to the nervous system. Occurrence of cancer in nostrils mainly due to the use of hardwoods is an additional risk. With regard to the basic lighting conditions, it was found that half of workshops had deficiencies in special carving areas, because they were below the minimum allowable lighting limit level (500 lux). With relation to noise, all the workshops exceeded the permissible maximum limit value (85 dBA). With respect to the occurrence of occupational events, no data were found in the companies, or analysis of employee absenteeism due to the exposure to particulate matter.

Development and evaluation of an exposure control efficacy library (ECEL)

OBJECTIVES

This paper describes the development and evaluation of an evidence database on the effectiveness of risk management measures (RMMs) to control inhalation exposure. This database is referred to as Exposure Control Efficacy Library (ECEL).

METHODS

A comprehensive review of scientific journals in the occupational hygiene field was undertaken. Efficacy values for RMMs in conjunction with contextual information on study design, sampling strategy and measurement type (among other parameters) were stored in an MS Access database. In total, 433 efficacy values for six RMM groups (i.e. enclosure, local exhaust ventilation, specialized ventilation, general ventilation, suppression techniques and separation of the worker) were collected from 90 peer-reviewed publications. These RMM categories were subdivided into more specific categories.

RESULTS

Estimated average efficacy values ranged from 87% for specialized ventilation to 43% for general ventilation. Substantial variation in efficacy values was observed within RMM categories based on differences in selected covariables within each study (i.e. study design, sampling strategy, measurement type and others). More contrast in efficacy values was observed when evaluating more detailed subcategories.

CONCLUSIONS

It is envisaged that ECEL will contribute to exposure modelling, but should be supplemented with expert opinion, preferably in a formal expert elicitation procedure. The work presented here should be considered as a first attempt to collate and analyse RMM efficacy values and inclusion of additional (unpublished) exposure data is highly warranted.

Results of inspections in health hazard industries in a region of the state of Washington

Results from state of Washington Occupational Safety and Health Administration (OSHA) health inspections were reviewed to characterize the level of control that existed at the work sites, identify common problems, and assess the success of targeting programs in finding and correcting uncontrolled health hazards. Data were obtained from 170 inspections conducted by industrial hygienists in a four-county area in 12 industries, including 10 that were targeted. Inspection data were accessed through the use of electronic databases and inspection reports then summarized by the following industries: bathtub refinishing, carbide tool and saw sharpening, fibercement siding installation, furniture refinishing, health care clinics, janitorial floor waxing service, landscaping, lawn maintenance, tree service, road construction, stone countertop fabrication, truck bed lining, warehouse and cold storage, and wood floor finishing. Targeted health hazards included worker exposure to airborne contaminants, noise, and bloodborne pathogens typical of the industry. Method and effectiveness of control of health hazards were evaluated by counting work sites with violations associated with engineering control, personal protective equipment, hearing conservation, or training. Results are presented by industry for the number and percentage of work sites that failed to provide required protection. Poor control of health hazards was generally found across all inspected industries. Follow-up inspections and self-reports of abatement found that more than 85% were able to successfully control the hazards and abate the violations. The results are further discussed as they relate to methods of control and risk and identifying existing and emerging high health hazard industries. Based on employment data and the poor hazard control that was found, most if not all the industries can be described as high health hazard, small-employer industries. The results can be used for the planning of interventions in other regions and industries.

Design and analysis of group-randomized trials in cancer: a review of current practices

BACKGROUND

Previous reviews have identified problems in the design and analysis of group-randomized trials in a number of areas. Similar problems may exist in cancer research, but there have been no comprehensive reviews.

METHODS

We searched Medline and PubMed for group-randomized trials focused on cancer prevention and control that were published between 2002 and 2006. We located and reviewed 75 articles to determine whether articles included evidence of taking group randomization into account in establishing the size of the trial, such as reporting the expected intraclass correlation, the group component of variance, or the variance inflation factor. We also examined the analytical approaches to determine their appropriateness.

RESULTS

Only 18 (24%) of the 75 articles documented appropriate methods for sample size calculations. Only 34 (45%) limited their reports to analyses judged to be appropriate. Fully 26 (34%) failed to report any analyses that were judged to be appropriate. The most commonly used inappropriate analysis was an analysis at the individual level that ignored the groups altogether. Nine articles (12%) did not provide sufficient information.

CONCLUSIONS

Many investigators who use group-randomized trials in cancer research do not adequately attend to the special design and analytic challenges associated with these trials. Failure to do so can lead to reporting type I errors as real effects, mislead investigators and policy-makers, and slow progress toward control and prevention of cancer. A collaborative effort by investigators, statisticians, and others will be required to ensure that group-randomized trials are planned and analyzed using appropriate methods so that the scientific community can have confidence in the published results.

"Pizza is cheaper than salad": assessing workers' views for an environmental food intervention

OBJECTIVE

"Images of a Healthy Worksite" aims to provide easy access to healthful foods and to reduce sedentarism at the worksite-to prevent weight gain. Formative research for the nutrition intervention component was aimed at gaining a broad understanding of the sociocultural role of food and eating among workers and worker perspectives on socially feasible and culturally acceptable environmental intervention strategies.

RESEARCH METHODS AND PROCEDURES

Using an adapted PRECEDE health planning model, we conducted ecological, educational, environmental, and administrative assessments at the worksite. Through 15 in-depth interviews, five focus groups, and community mapping at two sites with 79 administrators, managers, workers, and food service personnel (51% men, 82% white), we assessed workers' perspectives on physical, sociocultural, economic, and policy environments. Data were coded for predisposing, enabling, and reinforcing factors related to intervention strategies in vending, cafeteria, catering, and informal food environments. After classification for reach, intensity, and sustainability, objectives and evaluation plans were developed for each highly ranked strategy.

RESULTS

Key sociocultural factors affecting food and eating included: stress-related eating in a downsizing workplace, enthusiasm for employer-sponsored weight gain prevention efforts that respect personal privacy, and the consequences of organizational culture on worker access to the food and eating environment. Workers supported healthier cafeteria and catering options, bringing healthful foods closer, and labeling of healthful options.

DISCUSSION

We provide a practical and systematic approach to formative research and assess the interrelatedness of the physical, policy, economic, and sociocultural factors that affect environmental worksite interventions to prevent weight gain among employees.

Mapping safety interventions in metalworking shops

OBJECTIVE

This paper describes the selection of intervention activities designed to lower machine-related hazards and amputations in small metal fabrication businesses.

METHODS

Methods included an advisory board, employee discussions, and pilot tests. We used a stepwise intervention mapping process to identify performance objectives, behavioral determinants, and change objectives for two target populations (business owners and employees).

RESULTS

Intervention activities for owners were designed to increase knowledge about machine safety, encourage adoption of safety procedures, and motivate improvements in machine guarding. Intervention activities aimed at employees focused on building knowledge and skills of health and safety committee members.

CONCLUSIONS

The intervention mapping approach led to important insights about program goals and intervention activities. Intervention mapping also ensured a systematic and thorough review of each target population in the context of our research goals.

The occupational health field in the cochrane collaboration

It is the aim of the Cochrane Collaboration to gather, summarise and disseminate evidence of health care interventions. Recently, the Occupational Health Field has started to do so for occupational health interventions. In this article we would like to describe the organisation and the methods used by the Field. First, the use of research information to improve the quality of occupational health practice is explained. Next, the process and contents of Cochrane Reviews are described. The pros and cons of Cochrane Reviews are listed and what occupational health practitioners can learn from it. There is a great variety of occupational health interventions that requires flexibility in which research design to use. The Occupational Health Field will enhance our understanding of the effectiveness of occupational health interventions in the coming years.

A probabilistic assessment of the impact of interventions on oncology nurses' exposure to antineoplastic agents

OBJECTIVE

The main goal was to investigate the potential of a probabilistic approach for exposure assessment and use this information to evaluate the impact of a complex of policy actions/interventions on dermal exposure to antineoplastic agents among oncology nurses. The central theme of this study was to make optimal use of existing data, supplemented only with limited additional information from a questionnaire survey.

METHODS

A task based exposure model was used to estimate dermal exposure of the hands among oncology nurses in non-academic hospitals in the Netherlands. Monte Carlo simulation was used to integrate information from available (exposure) studies and generate exposure distributions for the total population of oncology nurses in both pre- and post-intervention situation. Graphs and descriptive statistics of the simulated exposure distributions were used to evaluate trends in population exposure.

RESULTS

The inventory showed that important intervention occurred in the preparation and administering of antineoplastic agents and in the handling of urine. Hardly any changes were identified in de nursing tasks. The use of gloves seemed to have decreased for a number of tasks. The results of the analysis show that the interventions did not affect the median exposure. However frequencies of occurrence of individuals with very high and very low total dermal exposures decreased substantially in the post-intervention situation. Analysis of the effect of pregnancy showed that pregnancy is very unlikely to influence exposure or any of the key input variables.

CONCLUSIONS

The present study shows that the probabilistic approach adds valuable information to deterministic exposure assessment, especially when extrapolating data on a subpopulation to populations of individuals at large. The results show that the identified changes in the past decade in Dutch non-academic hospitals resulted in changes in the exposure distribution of antineoplastic agents among oncology nurses.

Small business owners' health and safety intentions: a cross-sectional survey

BACKGROUND

Little is known about the variables underlying small business owners' behavioural intentions toward workplace health and safety. This project explores the relationship between three mediating variables (Attitude Toward Safety, Subjective Norm and Perceived Behavioural Control) and owners' Intentions Toward Safety, following the Theory of Planned Behaviour. We also investigate the role of beliefs underlying each mediating variable.

METHODS

Seven hundred businesses (5-50 employees) were randomly selected from 4084 eligible companies in a manufacturing business database (SIC codes 24 to 39). The 348 respondents are on average 51 yrs of age, 86% male, 96% white and have 2 to 4 years of post-secondary school.

RESULTS

All three mediator variables are significantly correlated with Intentions Toward Safety; Attitude Toward Safety shows the strongest correlation, which is confirmed by path analysis. Owners with higher attitudes toward safety have a higher probability of believing that improving workplace health and safety will make employees' healthier and happier, show that they care, increase employee productivity, lower workers' compensation costs, increase product quality and lower costs.

CONCLUSION

These results suggest that interventions aimed at increasing owners' health and safety intentions (and thus, behaviours) should focus on demonstrating positive employee health and product quality outcomes.

Improving the prevention and control of hazardous substance exposures: a randomized controlled trial in manufacturing worksites

BACKGROUND

New measures of exposure prevention (EP) activity were used to evaluate the effectiveness of a 16-month management-focused intervention addressing hazardous substance exposures in manufacturing work settings.

METHODS

EP efforts were assessed using a rating scheme developed for this study. The rating scheme yields a set of measures of exposure potential and protection, which are combined into an overall EP summary rating. A randomized, controlled design was used to assess intervention effectiveness. Fifteen large manufacturing worksites completed the 16-month intervention and follow-up assessments. Analyses were conducted on the 107 production processes assessed at both baseline and final.

RESULTS

Patterns of improvement within the intervention condition were consistent with the intervention emphasis on upstream or source-focused intervention; whereas patterns in controls were consistent with prevalent practice (more downstream, worker-focused). A mixed model analysis of variance showed greater improvement in EP ratings in intervention versus controls, but the difference in improvement was moderate and statistically non-significant.

CONCLUSIONS

This study has demonstrated that EP efforts in the manufacturing sector can be systematically assessed across the full range of hazardous substances in use, and that such assessments can serve both needs assessment and effectiveness evaluation functions. Findings suggest that more sustained or intense management-focused intervention would significantly improve EP activity in manufacturing settings.

Effectiveness of personal protective equipment: relevance of dermal and inhalation exposure to chlorpyrifos among pest control operators

This study assessed the effectiveness of a custom fit personal protective equipment (PPE) program aimed at reducing occupational exposure to pesticides. The intervention study was carried out on 15 pest control operators (PCOs) during mixing/loading and application of chlorpyrifos. Each worker was measured twice; first while the worker used PPE as normal (baseline measurement), and second after making some adjustments to the PPE (postintervention measurement). The applied intervention consisted of a tight-fitting, full-face respirator, fit-testing, long gloves, chemical-proof boots, a Tyvek hood, and an instruction video that was shown prior to putting on the PPE. A comprehensive evaluation program was used for the within-subject comparisons, including assessment of potential dermal exposure, actual dermal exposure, inhalation exposure, and internal dose as measured by the urinary metabolite 3,5,6-trichloro-2-pyridinol (TCP). The PPE program resulted in a significant increase in fit factors from a mean of 670 to 132,000. Actual dermal exposure levels decreased on average by fourfold after implementation of the PPE program (baseline AM = 132.1 microg; postintervention AM = 32.6 microg). The TCP levels in urine collected 24-32 hours after spray activities were lower in the postintervention data set (AM = 21.2 microg TCP/g creatinine vs. AM = 13.9 microg TCP/g creatinine). However, it is impossible to attribute these differences totally to the PPE program since workers had significant and varying urinary TCP levels before onset of spraying activities. Linear regression models showed that dermal exposure was only a predictive parameter for TCP levels in urine in the baseline data set. Although the results should be interpreted cautiously this study suggests a protective effect of the evaluated PPE program.

Design and analysis of group-randomized trials: a review of recent practices

We reviewed group-randomized trials (GRTs) published in the American Journal of Public Health and Preventive Medicine from 1998 through 2002 and estimated the proportion of GRTs that employ appropriate methods for design and analysis. Of 60 articles, 9 (15.0%) reported evidence of using appropriate methods for sample size estimation. Of 59 articles in the analytic review, 27 (45.8%) reported at least 1 inappropriate analysis and 12 (20.3%) reported only inappropriate analyses. Nineteen (32.2%) reported analyses at an individual or subgroup level, ignoring group, or included group as a fixed effect. Hence increased vigilance is needed to ensure that appropriate methods for GRTs are employed and that results based on inappropriate methods are not published.

An exposure prevention rating method for intervention needs assessment and effectiveness evaluation

This article describes a new method for (1) systematically prioritizing needs for intervention on hazardous substance exposures in manufacturing work sites, and (2) evaluating intervention effectiveness. We developed a checklist containing six unique sets of yes/no variables organized in a 2 x 3 matrix of exposure potential versus protection (two columns) at the levels of materials, processes, and human interface (three rows). The three levels correspond to a simplified hierarchy of controls. Each of the six sets of indicator variables was reduced to a high/moderate/low rating. Ratings from the matrix were then combined to generate a single overall exposure prevention rating for each area. Reflecting the hierarchy of controls, material factors were weighted highest, followed by process, and then human interface. The checklist was filled out by an industrial hygienist while conducting a walk-through inspection (N = 131 manufacturing processes/areas in 17 large work sites). One area or process per manufacturing department was assessed and rated. Based on the resulting Exposure Prevention ratings, we concluded that exposures were well controlled in the majority of areas assessed (64% with rating of 1 or 2 on a 6-point scale), that there is some room for improvement in 26 percent of areas (rating of 3 or 4), and that roughly 10 percent of the areas assessed are urgently in need of intervention (rated as 5 or 6). A second hygienist independently assessed a subset of areas to evaluate inter-rater reliability. The reliability of the overall exposure prevention ratings was excellent (weighted kappa = 0.84). The rating scheme has good discriminatory power and reliability and shows promise as a broadly applicable and inexpensive tool for intervention needs assessment and effectiveness evaluation. Validation studies are needed as a next step. This assessment method complements quantitative exposure assessment with an upstream prevention focus.