Individual, physical, and organizational risk factors for musculoskeletal disorders among municipality solid waste collectors in Shiraz, Iran

Work-related musculoskeletal disorders among desludging operators in Uganda

BACKGROUND

Despite the limited evidence, desludging operators remain at a heightened risk of work-related musculoskeletal disorders (WMSDs). This study established the prevalence and predictors of WMSDs among desludging operators in Uganda.

METHODS

A digitalized structured questionnaire was used to collect cross-sectional data on musculoskeletal disorders and routine workplace activities from 303 desludging operators in 11 cities in Uganda. These cities were purposively selected based on the presence of a fecal sludge treatment plant or wastewater treatment plant. The Nordic Musculoskeletal Questionnaire (NMQ) was used to assess WMSDs. Simple random sampling with replacements was used to select respondents. Data were analyzed using STATA version 15.0. Modified Poisson Regression was used to measure the strength of association between the independent variables and WMSDs.

RESULTS

A total of 303 study participants were interviewed (97.7% response rate). The average age of the respondents was 34.0 years (SD ± 9.8). The prevalence of WMSDs among desludging operators was 29.7%. The body parts affected by MSDs were; the elbow for 4.6% (14/303), shoulder for 5.0% (15/303), and wrist/hand for 6.3% (19/303) of the respondents. At multivariable analysis, after controlling for age, desludging operators' ability to influence the availability of equipment needed to do their work (APR = 0.45, 95% CI: 0.20-0.99), and feeling that everything done was an effort (APR = 1.70, 95% CI: 1.01-2.87) were significantly associated with WMSDs.

CONCLUSION

The prevalence of WMSDs was high among desludging operators in Uganda. Desludging operators' ability to influence the availability of equipment needed to do their work and frequency of feeling that everything done was an effort were significantly associated with WMSDs. Interventions should focus on ensuring adequate provision of ergonomic equipment and promoting practices that reduce the physical strain associated with desludging tasks. Additionally, comprehensive training programs addressing proper lifting techniques and posture awareness could significantly mitigate the risk of WMSDs among desludging-operators.

Structural equation modelling of work related musculoskeletal disorders among dumper operators

The aim of this study is to investigate the impact of personal factors, habitual factors, and work-related factors on work-related musculoskeletal disorders (WRMSDs) among dumper operators. In total, 248 dumper operators working in an iron ore mine were considered for this study. A questionnaire was developed and administered to collect dumper operators' personal, habitual, and work-related data. The reliability of the questionnaire was cross-checked by Cronbach alpha and the test-retest method. The values of Cronbach alpha for all latent variables were above 0.7, and the correlation coefficient of the questionnaire items at Time 1 and Time 2 was above 0.82. After verifying the validity (i.e., convergent and divergent) of the questionnaire data, the relationship between the factors under consideration was examined by structural equation modeling (SEM). The SEM demonstrated a moderate fit, with [Formula: see text] value of 1.386, comparative fit index (CFI) of 0.86, goodness-of-fit index (GFI) of 0.72, adjusted goodness-of-fit index (AGFI) of 0.69, Tucker-Lewis Index (TLI) of 0.83, normed fit index (NFI) of 0.71 and root mean square error of approximation (RMSEA) of 0.051. The SEM analysis revealed a positive relationship between WRMSDs and personal factors (with path coefficient = 0.313 and p < 0.05) as well as work-related factors (with path coefficient = 0.296 and p < 0.05). However, the relationship between WRMSDs and habitual factors was not statistically significant (with path coefficient = 0.142 and p > 0.05). Overall, this study provides valuable insights into the factors that influence the prevalence of WRMSDs among dumper operators. The findings highlight the significance of personal and work-related factors by which one can make a positive decision to prevent and reduce the incidence of WRMSDs among dumper operators.

Magnitude and possible risk factors of musculoskeletal disorders among street cleaners and solid waste workers: a cross-sectional study

BACKGROUND

In the absence of a standardized work environment, insurance system, occupational safety measures and expanding workload an uptrend of musculoskeletal disorders secondary to occupational hazards is observed among a wide range of occupations in developing countries including street sweepers/cleaners. The aim of this study is to determine the burden and potential factors associated with musculoskeletal disorders among street cleaners/solid waste collectors in Gondar town, Ethiopia.

METHODS

A cross-sectional study design was used to determine the burden and identify potential risk factors of musculoskeletal disorders among street cleaners. Street cleaners (n = 422) working experience of at least one year were randomly selected from the community at their respective work sites (street). A face-to-face interview recorded the participant's response addressing socio-demographic, occupational, job satisfaction, disability related to basic ADL, physical measurements, and self-reported pain using the Nordic-Musculoskeletal questionnaire. The logistic regression model was created to identify potential factors associated with self-reported MSDs.

RESULTS

The sample consists of women street sweepers/cleaners (100%, n = 422, response rate 100%) with at least one-year of work experience with a mean age of 37.03 ± 8.26. About 40% of women sweepers were illiterate and 95% reported no job satisfaction. The overall prevalence of MSDs was 73% (n = 308, 95% CI; 68.5, 77.2), among them nearly 65% reported having experienced disability in performing basic ADL in the past 12 months. Low back pain was the most prevalent region (n = 216, 70.1% case versus MSDs n = 308). In univariate and multivariate logistics analysis, being overweight/obese (AOR of 4.91 (95%, 2.22, 10.87)), age group 35 and above (AOR 2.534 (1.51, 4.26)), not-satisfied with job (AOR 2.66 (1.05, 6.75)), and street cleaning distance of longer than 2 km (AOR 2.82 (1.64, 4.83)) were significantly associated with self-reported musculoskeletal disorder..

CONCLUSION

This study demonstrated higher self-reported MSDs among street sweepers/cleaners. Modifiable predictors like overweight, lack of job satisfaction, and cleaning longer distance were identified to be associated. Hence, there is a need for ergonomic measures and policy to curb these factors to reduce the burden of MSD among women street sweepers.

Effectiveness of a theory-based educational intervention on work-related musculoskeletal disorders preventive behaviors among assembly-line female workers: a study protocol for a randomized controlled trial

BACKGROUND

The use of preventive behaviors of musculoskeletal disorders (MSDs) requires proper training, which leads to correct decisions regarding maintaining postures at work and performing stretching exercises. Due to very repetitive work, applying manual force, improper postures, and static contractions of proximal muscles, assembly-line female workers suffer from musculoskeletal pains. It is assumed that structured and theory-based educational intervention using a learning-by-doing (LBD) approach may increase the preventive behaviors against MSDs and reduce the consequences of these disorders.

METHODS

This randomized controlled trial (RCT) will be conducted in three phases: phase 1: validation of the compiled questionnaire, phase 2: determining the social cognitive theory (SCT) constructs that predict the preventive behaviors of MSDs in assembly-line female workers, and phase 3: designing and implementing the educational theory. The educational intervention is based on the LBD approach, and the study population includes assembly-line female workers in electronic industries of Iran, who are randomly divided into two intervention and control groups. The intervention group received the educational intervention in the workplace and the control group does not receive any intervention. The theory-based educational intervention includes evidence-based information along with pictures, fact sheets, and published literature about a good posture at work and the need to perform proper stretching exercises. The educational intervention aims to improve the knowledge, skills, self-efficacy, and intention of assembly-line female workers to adopt preventive behaviors of MSDs.

DISCUSSION

The present study will evaluate the effects of maintaining a good posture at work and performing stretching exercises on the adherence to preventive behaviors of MSDs among assembly-line female workers. The developed intervention is easily implemented and evaluated in a short period of time based on the improved score of the rapid upper limb assessment (RULA) method and the mean score of adherence to stretching exercises and can be provided by a health, safety, and environment (HSE) expert.

TRIAL REGISTRATION

ClinicalTrials.gov IRCT20220825055792N1. Registered on 23 September 2022 with the IRCTID.

Prevalence, pattern and risk factors for work-related musculoskeletal disorders among Nigerian plumbers

Plumbing work is more manually driven in low-and-middle income countries (LMICs), and the prevalence of work-related musculoskeletal disorders (WMSDs) among workers who engage in plumbing in LMICs may be worse than earlier reports from developed countries. This study aimed to assess the prevalence, pattern and risk factors for work-related musculoskeletal disorders (WMSDs) among Nigerian plumbers. A total of 130 consenting plumber participated in this cross-sectional study. The Nordic Musculoskeletal questionnaire and the Job Factor Questionnaire were used to assess information on prevalence and pattern of WMSDs; and perceptions regarding work-related risks factors for WMSDs. Descriptive (mean, frequency, range, percentage and standard deviation) and inferential (Chi-square) statistics were used to analyze data. Alpha level was set at p<0.05. The mean age of the respondents is 36.56 ± 10.418 years. The mean years of experience and working hours per day are 14.15 ± 9.161 years and 8.28 ± 2.512 hours. Job characteristics were mostly installation of pipes and fixtures (99.2%), equipment and fixtures prior to installation (96.9%), and testing of plumbing system for leaks (88.5%). 12-month and 7-day prevalence of WMSDS were 84.6% and 50.8%. Low-back (63.8%), neck (55.4%) and knee (50%) were the most affected body sites. Having WMSDs limits normal activities involving the low-back (32.3%), knee (25.4%) and neck (23.8%). There was significant association between 12-month prevalence of WMSDs and use of saws and pipe cutters (χ² = 4.483; p = 0.034), while sites of affectation had significant association with 12-month and 7-day prevalence of WMSDs (p<0.05) respectively. Nigerian plumbers have a high prevalence of WMSDs affecting most commonly the low back, neck and knee. Plumbing job factors pose mild to moderate risk to developing WMSDs, and use of saws and pipe cutters significantly influence WMSDs.

Job-related stress associated with work-related upper extremity musculoskeletal disorders (UEMDs) in municipal waste collectors: the moderation and mediation effect of job support

Background

Since the policy of “keeping trash off of the ground” in Taiwan, long-term exposure to repetitive motion in waste collection process results in high risk of upper extremity musculoskeletal disorders (UEMDs). Thus, we assessed the moderation and mediation effects of job-related stress and job support on work-related UEMDs among municipal waste collectors.

Methods

A cross-sectional study was conducted in two cities located at northern Taiwan during 2018–2019. 626 municipal waste collectors voluntarily participated and anonymously filled out a structured questionnaire. The moderation and mediation effects of effort-reward imbalance (ERI) and social support on UEMDs were analyzed by Haye’s Process Macro Model.

Results

Prevalence of UEMDs in municipal waste collectors were 43.4% for neck, 56.0% for shoulder, 24.1% for upper back, and 33.1% for hand/wrist. There was high prevalence of shoulder (72.2%), neck (48%), and upper back (30%) in female workers compared to male, most significantly in shoulders. In univariate and multivariate analysis, high ERI and low job support were significantly associated with ORs of 3.11 (95% CI:1.58–6.13) for elbow, 2.79 (95% CI:1.39–5.56) for shoulder, 3.39 (95% CI:1.64–7.00) for upper back and 3.83 (95% CI:1.98–7.41) for hand/wrist. Prevalent UEMDs were positively associated with high ERI in municipal waste collectors but negatively with job support. The moderation effects of ERI and job support on UEMDs, of which the measured synergy index exceeded one, were 18.24 for shoulder, 3.32 for elbow, and 2.45 for hand/wrist, but mediation effects were not significant.

Conclusions

This study found municipal waste collectors with work-related upper extremity disorders were significantly associated with work-related psychological risk factors. Therefore, waste collection cannot only to be improved by semi-automatic and automatic processes but immediate intervention programs for the reduction of psychological risk factors is needed promptly.

Status of resource recycling stations in Taiwan and recycling work-related health effects

Resource recycling has become an integral part of environmental protection efforts. At present, the development of Taiwan's resource recovery and related works are quite mature. However, laborers or volunteers working in resource recycling stations may be exposed to different types of hazards during the recycling process. These hazards can be divided into biological, chemical, and musculoskeletal problems. These hazards are usually related to the work environment and work habits; therefore, a related control strategy is needed. Tzu Chi's recycling business has been running for over 30 years. In addition to leading the trend of resource recycling in Taiwan, many elderly people have also participated in Tzu Chi recycling stations as volunteers. These older volunteers may be more sensitive to exposure to hazards, and thus the focus of this review is to illustrate the possible hazards and health impacts of resource recovery work and to recommend relevant interventions to improve occupational health during resource recovery work.

Moderating and Mediating Effects of Over-Commitment on the Association Between Effort–Reward Imbalance (ERI) with Upper Back and Hand/Wrist Disorders in Municipal Solid Waste Collectors

Purpose

Methods

Results

Conclusion

Dor nas extremidades inferiores, demandas físicas e psicológicas em trabalhadores da limpeza urbana: estudo transversal

Resumo Objetivo: descrever as características do trabalho e investigar a prevalência e os fatores associados à dor em membros inferiores em trabalhadores da limpeza urbana. Métodos: estudo de corte transversal, realizado na Bahia. Dados coletados entre 2009 e 2010. A dor foi avaliada por meio do Nordic Musculoskeletal Questionnaire, enquanto as demandas psicossociais no trabalho foram medidas pelo Job Content Questionnaire. Também foram avaliadas as demandas físicas, incluindo posturas gerais e manuseio de carga. A análise de regressão logística múltipla foi utilizada para identificar fatores associados à dor em membros inferiores. Resultados: 624 trabalhadores participaram da pesquisa. Constatou-se alta prevalência de dor em membros inferiores nos últimos sete dias (23,7%) e nos últimos doze meses (42,1%), sendo maior entre agentes de limpeza e coletores. A dor em membros inferiores foi associada a: mais de três anos de trabalho na empresa (OR = 1,34); alta exposição ao manuseio de cargas (OR = 1,35); demanda psicológica no trabalho (OR = 1,87); e condicionamento físico insuficiente (OR = 1,67). O trabalho na limpeza urbana envolveu grande sobrecarga física, com pressão de tempo para sua execução. Conclusão: evidenciou-se a necessidade de medidas para redução do manuseio de cargas e de mudanças na organização do trabalho, incluindo pausas durante a jornada e adequação das tarefas ao tempo disponível, a fim de evitar sobrecargas física e psicológica dos trabalhadores.

Health concerns among waste collectors during pandemic crisis

The COVID-19 pandemic has negatively affected the economic, social, and psychological aspects globally. COVID-19 can possibly spread through municipal solid waste (MSW) if it is collected, bagged, transported, and disposed inappropriately. Such situation has posed significant challenges to MSW management (MSWM), which has led waste personnel under massive pressure. This study aims to examine the health-protective behavior of sanitation workers/MSW collectors (MSWCs) during the COVID-19 crisis. Quantitative data were collected by using a self-administered survey from 418 MSWCs working in Mainland China. The study extended the traditional health-belief model and proposed education and training as a facet of the behavioral model. Result showed that education and training were a significant predictor of health-protective behavior. Moreover, the moderating incremental influence of regulative assistance significantly affected the behavioral mapping of MSWCs. This study contributes to the literature by mapping the concerns, risks, and challenges experienced by MSWCs in times of a health crisis. Policymakers should specially consider the safety and hygiene concerns of frontline workforce in the whole chain of waste management (including the outsourced operations of MSWM). Lastly, the adoption of smart communication with the frontline workforce (i.e., MSWCs) is in dire need to maintain trust and avoid rumors and misconceptions during the time of a pandemic situation.

Assessing the effectiveness of an ergonomics intervention program with a participatory approach: ergonomics settlement in an Iranian steel industry

PURPOSE

Work-related musculoskeletal disorders (WMSDs) are common occupational problems affecting the health and productivity of workers worldwide. Ergonomic intervention programs (EIPs) can play an effective role in preventing these disorders in the workplace. Assessing the effectiveness of an EIP is a challenge faced by both industries and researchers. This study was aimed at assessing the effectiveness of an EIP on human resources productivity (HRP), musculoskeletal disorders (MSDs), general health and occupational fatigue in a steel industry.

METHODS

This study was conducted in a steel industry in Isfahan, Iran, between 2018 and 2021. To assess the effectiveness of the EIP with a participatory approach, training and redesign of workstations, the criteria of HRP, MSDs, general health and occupational fatigue were investigated before and after the intervention, using HRP Questionnaire, Nordic musculoskeletal questionnaire (NMQ), 28-item General Health Questionnaire (28-GHQ), Swedish Occupational Fatigue Inventory (SOFI-20) and Occupational Fatigue/Exhaustion Recovery (OFER-15) Questionnaire, as data collection tools, respectively.

RESULTS

The implementation of EIP in the studied industry significantly led to an increase in HRP (p < 0.05). The prevalence of MSDs decreased significantly in most regions of the body after the interventions (p < 0.001). In addition, the program significantly improved general health (p < 0.001) and reduced occupational fatigue among employees (p < 0.001).

CONCLUSIONS

The implementation of EIP was significantly effective in working conditions improvement. Therefore, implementing EIP with participatory approach, workforce training, as well as redesigning of workstations are recommended in industries.

Evaluation of a passive low-back support exoskeleton (Ergo-Vest) for manual waste collection

The purpose of study was to determine the biomechanical, physiological, and subjective effect of a Passive Exoskeleton device (called Ergo-Vest) among 20 waste collectors in the working environment. Compression force and moment on L4/L5 related to 400 critical postures of the participants were estimated using the 3DSSPP software. The heart rate and energy expenditure are measured as the physiological strain using the Polar RS400 Heart Rate Monitor. Borg scale perceived exertion, system usability scale, and ergonomic design indicators of the device were collected as the subjective parameters. Compression force and moment on L4/L5 disc were decreased when the Ergo-Vest was utilised. There was no significant difference in energy expenditure and heart rate with and without the device. The workers' perceived physical exertion was decreased while using the Ergo-Vest. From the perspective of end users, the usability and ergonomic design features of the Ergo-Vest was acceptable. Practitioner summary: The prevalence of musculoskeletal disorders is high among the Iranian waste collectors. To mitigate this occupational problem, the effect of a passive exoskeleton for lower-back support (Ergo-Vest) was investigated on the workers' spine loading, physiological parameters, and perceived physical exertion. The result shows spine force reduction and lower subjective responses.

Psychological stress and associated factors among municipal solid waste collectors in Hanoi, Vietnam: A cross-sectional study

INTRODUCTION

In low and middle-income countries, the manually operated municipal waste collection system prominently depended on the performance of waste collectors (WC). Most of the literature has focused on the impact of waste collection tasks on WCs' physical health, while little was known about the psychological effects of work-related stress. This study aimed to examine the prevalence of psychological stress and related factors among waste collectors in Hanoi, Vietnam.

METHODS

A cross-sectional survey was conducted among 802 WCs in 2017. The questionnaire included the 7-item Stress component of the 21-item Depression, Anxiety and Stress Scale, and questions on demographics and work conditions. Descriptive and multivariate logistics regression analyses were conducted to examine the factors related to psychological stress among WCs.

RESULTS

Results showed that 13.4% of WCs reported stress symptoms; among them, 3.3% of WCs experienced severe stress. Factors related to lower odds of self-reported psychological stress included self-perceived frequent exposure to high and low temperatures in the working environment (OR = 0.51 and 0.52, respectively). Factors associated with the increased likelihood of symptoms included frequent exposure to hot/flammable objects (OR = 2.41), working a night shift in the last three months (OR = 1.82), education lever lower than high school (OR = 1.82), and having an insufficient monthly income (OR = 1.99).

CONCLUSION

The high percentage of workers with severe stress implies the need for mental health prevention and treatment for WCs who participated in this study.

Prevalence of musculoskeletal disorders and risk factors in recyclable material waste pickers from the dump of the structural city in Brasília, Brazil

Solid waste management is a global challenge impacting the lives of thousands of people, among them the recyclable materials waste pickers, through the separation and sale of these materials, make a living for themselves. These workers face unhealthy working conditions and are exposed to various occupational risks, which predispose the prevalence of musculoskeletal as chronic back problems.

METHOD

Exploratory cross-sectional study with a semi-structured questionnaire to investigate the prevalence of back pain and related risk factors.

RESULTS

1.025 waste pickers were interviewed, and 970 records of chronic back pain were detected. Among them, 660 were women (68.04%), 310 were men (31.96%), the average age of 40.21 years; 597 were single (61.92%); 629 (64.84%) had over 11 years of work; 942 (97.11%) worked exclusively in the open dump, 899 (92.68%) with bags, 922 (95.05%) on dayshift. We found significant associations between gender (p < 0.001); age (p < 0.001); time at work (p < 0.022) and place at work (p < 0.001). After adjusting, there were higher prevalence of chronic back pain women (OR = 1.7), older age (OR = 2.64); working more than 11 years (OR = 1.09); and working on the open dump (OR = 2.8).

CONCLUSION

The prevalence of subjective symptoms of musculoskeletal disorders was high. Women, over 36 years old, who worked more than 11 h a day in the open dump were more exposed to suffer from chronic back problems. The importance of urgently addressing the labor impacts related to solid waste management in developing countries to protect these workers and, especially, women involved in this work is emphasized.

Musculoskeletal Disorder Symptoms among Workers at an Informal Electronic-Waste Recycling Site in Agbogbloshie, Ghana

Informal recycling of electrical and electronic waste (e-waste) has myriad environmental and occupational health consequences, though information about the chronic musculoskeletal health effects on workers is limited. The aim of this study was to examine the prevalence and intensity of self-reported musculoskeletal disorder (MSD) symptoms among e-waste workers at Agbogbloshie in Ghana-the largest informal e-waste dumpsite in West Africa-relative to workers not engaged in e-waste recycling. A standardized musculoskeletal discomfort questionnaire was administered to 176 e-waste workers (73 collectors, 82 dismantlers, and 21 burners) and 41 workers in a reference group. The number of body parts with musculoskeletal discomfort were 1.62 and 1.39 times higher for collectors and dismantlers than burners, respectively. A 1-week discomfort prevalence was highest for collectors (91.8%) followed by dismantlers (89%), burners (81%), and the reference group (70.7%). The discomfort prevalence for e-waste workers was highest in the lower back (65.9%), shoulders (37.5%), and knees (37.5%). Whole-body pain scores (mean ± SE) were higher for collectors (83.7 ± 10.6) than dismantlers (45.5 ± 7.6), burners (34.0 ± 9.1), and the reference group (26.4 ± 5.9). Differences in prevalence, location, and intensity of MSD symptoms by the e-waste job category suggest specific work-related morbidity. Symptom prevalence and intensity call attention to the high risk for MSDs and work disability among informal e-waste workers, particularly collectors and dismantlers.

Occupational Health Injuries by Job Characteristics and Working Environment among Street Cleaners in South Korea

In 2018, 1822 incidents relating to death or injury occurred among street cleaners in South Korea. However, South Korea currently lacks comprehensive studies on related injuries based on street cleaners’ job characteristics and environments in the country. This study analyzed injuries according to the job characteristics and environment through a survey of 150 Korean street cleaners working in the Seoul and Gyeonggi-do areas. This study assessed three category measures—demographic, job characteristics, and environments—to determine the effects of injuries. The demographic measures consisted of age, gender, and education level. Job characteristic variables consisted of length of time on the job, job contract, monthly income, working hours per day, working start time, overtime per month, and days off per month. For job environments, this survey included job duty, classification, main tasks, work intensity, and safety equipment. The data were analyzed according to descriptive statistics, injury ratio, and Probit regression analysis. The results of the analysis demonstrated that the participants with the highest risk of injury were mostly males with less than a middle school education. Assessment of the job characteristics showed that the most prevalent length of working experience was less than 5 years, with most engaging in contract/day work. A share of 36.67% of the participants reported injuries. The most prevalent reason for injury was overwork (32.73%), and the most frequent injury area was the lower back (49.09%). In summary, injuries among street cleaners were associated with education level, job experience, days off from work, and work intensity. As such, street cleaners should receive more education to decrease the risk of injuries, regardless of the number of employees or their contract status.

Psychological and physical job demands, decision latitude, and work-related social support among Iranian waste collectors

Waste collection is known as a stressful and physically demanding job in low/middle income countries. This study aimed to assess the psychological and physical job demands, decision latitude, and work-related social support among Iranian waste collectors. In this cross-sectional study, field observation, video capture, and unstructured interviews were performed to understand the process of waste collection. Data were collected from 200 waste collectors of Shiraz city using a demographic/work characteristics questionnaire and a job content questionnaire (JCQ). Logistic regression analysis was used for the prediction of independent variables affecting job content dimensions. A p < 0.05 was considered to be statistically significant. Results show that the rate of municipal solid waste (MSW) generation in Shiraz city was 0.576 kg/capita/day, which translates into about 1076 tons of waste per day per the current population of 1,869,001. The total amount of MSW produced in Shiraz over a four-year period from 2014 to 2017 were 346,093, 363,505, 392,869, and 400,863 tons, respectively. About half of the waste collectors reported high levels of psychological and physical job demands. More than half were concerned with the low level of decision latitude and social support in the workplace. Night-workers (OR = 3.29) and smokers (OR = 2.75) reported higher psychological job demands than day-workers and non-smokers, respectively. Decision latitude and social support were inversely associated with the level of education (OR = 1.90), and daily working time (OR = 2.46), respectively. Based on the Demand-Control-Support Model, waste collectors were exposed to relatively high levels of job stress associated with occupational risk factors.