Respiratory symptoms and lung function in relation to wood dust and monoterpene exposure in the wood pellet industry

Hearing loss and respiratory health symptoms among large-scale sawmill workers of the timber processing factories within the Gert Sibande District Municipality: a comparative cross-sectional study

BACKGROUND

Occupational exposure to wood dust may cause respiratory illnesses, while prolonged exposure to loud noise may cause noise-induced hearing loss.

OBJECTIVE

The objective of the study was to assess the prevalence of hearing loss and respiratory symptoms among large-scale sawmill workers within the Gert Sibande Municipality in Mpumalanga Province, South Africa.

METHODS

A comparative cross-sectional study consisting of 137 exposed and 20 unexposed randomly selected workers was undertaken from January to March 2021. The respondents completed a semi-structured questionnaire on hearing loss and respiratory health symptoms.

DATA ANALYSE

The data was analysed using Statistical Package for Social Sciences (SPSS) version 21 (Chicago II, USA). The statistical analysis of the difference between the two proportions was done using an independent student t-test. The level of significance was set at p < 0.05.

RESULTS

There was a statistically significant difference between the exposed and unexposed workers on the prevalence of respiratory symptoms like phlegm (51.8 vs. 0.0%) and shortness of breath (chest pain) (48.2 vs. 50%). There was also a statistically significant difference between the exposed and unexposed workers on the signs and symptoms of hearing loss like tinnitus (ringing in the ears) (50 vs. 33.3%), ear infections (21.4 vs. 66.7%), ruptured ear drums (16.7 vs. 0.0%), and ear injuries (11.9 vs. 0.0%). The exposed workers reported always wearing personal protective equipment (PPE) (86.9%) compared to the unexposed workers (75%). The reason for not wearing PPE consistently by the exposed workers was due to not being available (48.5%), compared to the unexposed workers who reported other reasons (100%).

CONCLUSION

The prevalence of respiratory symptoms among the exposed workers was higher than that of the unexposed workers, except for chest pains (shortness of breath). The prevalence of symptoms of hearing loss among the exposed workers was higher than the unexposed workers, except for ear infections. The results suggest that measures should be implemented at the sawmill to help protect workers' health.

Exposure Characterization of Wood Dust Particulate, Endotoxins, and (1-3)-β-d-Glucans, and Their Determinants in Mozambiquan Wood Processing Workers

OBJECTIVES

Dust generated from wood processing comprises a heterogeneous mixture of inorganic and organic particles, including wood fragments, microorganisms, endotoxins, (1-3)-β-d-glucans, and allergens. This study characterized exposure to wood dust and its determinants in the Mozambiquan wood processing industry.

METHODS

A total of 124 personal inhalable samples, collected from a stratified random sample of 30 workers, were analysed for dust particulate, endotoxins, and (1-3)-β-d-glucans. Mixed-effects models were developed to investigate significant exposure determinants.

RESULTS

The geometric mean (GM) inhalable dust particulate concentrations were 3.29 mg m-3, 98 endotoxin units (EU) m-3, and 123 ng m-3 for (1-3)-β-d-glucans. Significant predictors for higher particulate levels included machinery (GMR = 1.93), sawing (GMR = 2.80), carpentry (GMR = 2.77), or painting (GMR = 3.03) tasks. Lebombo-ironwood species was associated with higher dust particulate levels (GMR = 1.97). Determinants of endotoxin concentrations included working with dry wood and damp cleaning methods, which were associated with lower levels. Working in closed buildings (GMR = 3.10) and dry sweeping methods were associated with higher (1-3)-β-d-glucan concentrations (GMR = 1.99).

CONCLUSIONS

Work tasks in certain exposure groups (machinery, sawing, carpentry, painting), processing certain wood species (Lebombo-ironwood) and working in closed buildings were associated with higher exposures, whilst using dry wood and damp cleaning practices reduced exposure levels.

Perturbations in indices of oxidative stress, oxidative DNA damage and lung function in chronic exposure to wood dust in Southern Nigeria

OBJECTIVES

Oxidative stress (OS) and oxidative DNA damage accruing from chronic exposure to wood dust have been implicated in the development of chronic lung conditions among woodworkers. Indices of OS, inflammation, oxidative DNA damage and lung function in relation to duration of exposure to wood dust were assessed in woodworkers to determine their possible utility as risk evaluation indices for chronic lung conditions.

METHODS

Ninety participants comprising 30 active woodworkers, 30 passive woodworkers, and 30 controls were enrolled into this cross-sectional study. The total plasma peroxides, total antioxidant capacity (TAC), oxidative stress index (OSI), malondialdehyde (MDA), reduced glutathione, nitric oxide, high sensitivity C-reactive protein (hs-CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and peak expiratory flow rate (PEFR) were determined in all participants.

RESULTS

Woodworkers had lower PEFR, TAC, and higher malondialdehyde, OSI, hs-CRP, and 8-OHdG compared to controls (p < 0.05). Active woodworkers had higher malondialdehyde, 8-OHdG, and hs-CRP compared to passive woodworkers (p < 0.05). Increasing duration of exposure to wood dust is associated with higher malondialdehyde, hs-CRP, and 8-OHdG in active woodworkers (p < 0.05) and higher 8-OHdG and hs-CRP in passive woodworkers (p < 0.05). Negative correlation was observed between hs-CRP and TAC (r=-0.367, p = 0.048) in active workers.

CONCLUSION

The association of exposure to wood dust with elevated indices of inflammation, OS, lipid peroxidation, oxidative DNA damage, and reduction in antioxidants and peak expiratory flow rate; and the concomitant increase in oxidative DNA damage and inflammation with increasing duration of exposure suggest that these indices may be useful in predicting woodworkers at risk of development of chronic lung conditions.

Chronic respiratory symptoms and lung function parameters in large-scale wood factory workers in Addis Ababa, Ethiopia: a comparative cross-sectional study

BACKGROUND

Occupational wood dust causes chronic respiratory health problems as well as a decline in lung function. However, data on the prevalence of chronic respiratory symptoms and lung function parameters among large-scale wood factories workers in Ethiopia producing furniture are limited. The objective of this study was to determine the prevalence of chronic respiratory symptoms, lung function measures, and associated factors among large-scale wood industry workers in Addis Ababa, Ethiopia.

METHODS

An institution-based cross-sectional study was conducted among 232 wood workers and 232 controls. Participants for the study were selected using stratified and systematic sampling from soft drink and wood factories. The chronic respiratory symptoms were assessed using a modified American Thoracic Society (ATS) questionnaire, and lung function tests were performed using an Easy on PC spirometer in accordance with the ATS standards for spirometry. The data were imported into Epi-data version 4.4.2 and analyzed with SPSS version 23. Poisson regression, Multivariate linear regression and multivariable logistic regression analysis were used.

RESULTS

The prevalence ratio of overall chronic respiratory symptoms was significantly higher among woodworkers (65.7%) compared to controls (23.3%) in this study (PR = 2.17, 95% CI: 1.51-3.12). Current chronic respiratory symptoms were associated with gender, and previous chronic respiratory disease. Woodworkers had significantly lower Forced vital capacity (FVC) and Forced expiratory volume in the first second (FEV1) when compared to controls.

CONCLUSION

Woodworkers had a higher prevalence of chronic respiratory symptoms and lower lung function measures, which lowered lung capacity when compared to controls. To reduce workers' exposure to wood dust, engineering control methods should be implemented.

Assessment of dust exposure and chronic respiratory symptoms among workers in medium scale woodwork factories in Ethiopia; a cross sectional study

Background

Wood dust in a form of inhalable particulates can penetrate the lung tissues and affect respiratory health. Woodwork factory workers are at a greater risk of developing respiratory health problems because of exposure in their working environment, but existing data were few. The aim of this study was to assess the prevalence of chronic respiratory symptoms, associated factors, and concentration of personal total wood dust level among medium-scale woodwork factory workers.

Methods

An institutional based cross-sectional study was conducted among 506 woodwork factory workers. We selected study participants using a simple random sampling technique. We assessed chronic respiratory symptoms using the British Medical Research Council respiratory symptoms questionnaire with a few modifications. A multivariate logistic regression model was used to identify the factors. Forty dust measurements were collected from 20 randomly selected workers using a closed-face cassette (CFC) personal sampler. We analyzed the dust samples gravimetrically using a standard microbalance scale.

Results

We recruited a random sample of 506 workers in the study with a response rate of 98%. The prevalence of chronic respiratory health symptoms among woodworkers was 69.8% with a prevalence of cough (54.6%), phlegm (52.2%), wheezing (44.6%), breathlessness (42.1%), and chest pain (42.9%). Past occupational dust exposure history (AOR = 2.09, 95% CI; 1.09–4.01), work experience > 5 years (AOR = 9.18, 95% CI; 5.27–16.00), using bio-fuel as energy for cooking (AOR = 2.42, 95% CI; 1.44–4.07), and having no occupational safety and health training (AOR = 3.38, 95% CI; 1.20–9.49) were factors that significantly associated with chronic respiratory symptoms among woodwork workers. The geometric mean (GM) of dust exposure level among woodworkers was 10.27 mg/m³, which exceeded the limit of 10 mg/m³ set by the ACGIH.

Conclusions

High prevalence of chronic respiratory symptoms was reported from woodwork factory workers. Increased work- experience, using bio-fuel as an energy source for cooking, past occupational dust exposure history, and having no occupational safety and health training were identified risk factors. The measured average personal wood dust exposure level was above the recommended occupational threshold limit value. Therefore, workers’ wood dust exposure reduction and control methods and respiratory health awareness programs should be implemented.

Peak Inhalation Exposure Metrics Used in Occupational Epidemiologic and Exposure Studies

Peak exposures are of concern because they can potentially overwhelm normal defense mechanisms and induce adverse health effects. Metrics of peak exposure have been used in epidemiologic and exposure studies, but consensus is lacking on its definition. The relevant characteristics of peak exposure are dependent upon exposure patterns, biokinetics of exposure, and disease mechanisms. The objective of this review was to summarize the use of peak metrics in epidemiologic and exposure studies. A comprehensive search of Medline, Embase, Web of Science, and NIOSHTIC-2 databases was conducted using keywords related to peak exposures. The retrieved references were reviewed and selected for indexing if they included a peak metric and met additional criteria. Information on health outcomes and peak exposure metrics was extracted from each reference. A total of 1,215 epidemiologic or exposure references were identified, of which 182 were indexed and summarized. For the 72 epidemiologic studies, the health outcomes most frequently evaluated were: chronic respiratory effects, cancer and acute respiratory symptoms. Exposures were frequently assessed using task-based and full-shift time-integrated methods, qualitative methods, and real-time instruments. Peak exposure summary metrics included the presence or absence of a peak event, highest exposure intensity and frequency greater than a target. Peak metrics in the 110 exposure studies most frequently included highest exposure intensity, average short-duration intensity, and graphical presentation of the real-time data (plots). This review provides a framework for considering biologically relevant peak exposure metrics for epidemiologic and exposure studies to help inform risk assessment and exposure mitigation.

Nasal lavage as analytical tool in assessment of exposure to particulate and microbial aerosols in wood pellet production facilities

Occupational exposure to wood dust and bioaerosols may lead to numerous respiratory tract diseases. We aimed to assess a degree of workplace contamination with dust, bacteria, fungi, endotoxins, and (1 → 3)-β-D-glucans released into the air during wood processing in pellet production facilities and to check against this background the usefulness of nasal lavage (NAL) as analytical tool for assessment of combined workers' exposure to airborne dust and microbiological contaminants. In 10 pellet plants, the particulate (wood dust) aerosol concentrations were determined by using Grimm aerosol spectrometer and CIS filter sampler. The collected CIS samples were subsequently used to evaluate endotoxin and (1 → 3)-β-D-glucan concentrations. Simultaneously with particulate aerosol, bioaerosol samples were collected by using 6-stage Andersen and single-stage MAS impactors. Bacterial and fungal aerosol concentrations were calculated and all isolated microorganisms were taxonomically identified. NAL fluid samples were collected from workers exposed to studied aerosols and the concentrations of proinflammatory mediators (IL-1β, IL-6, IL-8, and TNFα) and cytological image of nasal mucosa (expressed as cell counts) were established. The dynamics of production activities resulted in wide range of observed wood dust, microorganism, endotoxin and (1 → 3)-β-D-glucan concentrations reaching periodically extremely high values up to 65 mg m^-3, 19,320 CFU m^-3, 215 ng m^-3 and 1525 ng m^-3, respectively. Environmental stress caused by exposure to particulate and microbial aerosols stimulated immune response among workers of pellet production facilities. Correlation analysis revealed that interleukin levels and the number of cells in NAL were significantly affected by both wood dust and bioaerosol concentrations. As nasal mucosa serves as the primary barrier against inhaled pollutants, NAL seems a reliable analytical material to assess work-related adverse respiratory health outcomes derived from such exposure.

Impact of habitual marijuana and tobacco smoke on severity of chronic rhinosinusitis

PURPOSE

Health concerns around cannabis (marijuana) use have focused on the possible relationship with psychosis and lower airway health, however; the effect of cannabis smoking on upper airway health has received less attention. The aim of this study is to investigate difference between exclusive tobacco cigarettes smoking compared with tobacco plus cannabis smoking regarding severity of chronic rhinosinusitis (CRS).

MATERIAL AND METHODS

A prospective cross-sectional study with two groups of CRS patients recruited (Group 1: tobacco cigarettes smokers; 100 patients and group 2: tobacco cigarettes smokers and also cannabis users; 100 patients). Recruitment occurred in a general practice in Egypt. Cannabis use was recorded by self-report. Severity of CRS was assessed and compared between 2 groups using SNOT-20 questionnaire, Lund-Mackay CT score and Lund-Kennedy (LK) endoscopy Score.

RESULTS

Group 2 patients (tobacco plus cannabis smokers) had significantly higher mean of assessment cores (SNOT-20 (P = 0.005), Lund-Mackay CT score (P = 0.006) and Lund-Kennedy (LK) endoscopy Score (P = 0.005)). Group 2 patients also had significantly higher mean of facial pain/pressure, difficulty sleep, and wake at night, lack of sleep, wake up tired, fatigue, reduced productivity, reduced concentration, frustration/restless/irritable, sad and embarrassed compared to patients in group 1.

CONCLUSION

Adult patients who smoked tobacco cigarettes plus cannabis mixed with tobacco had greater health related quality of life burden and more severe CRS compared to patients who smoked tobacco cigarettes only.

High Prevalence of Respiratory Symptoms among Particleboard Workers in Ethiopia: A Cross-Sectional Study

Work in the wood industry might be associated with respiratory health problems. The production of particleboard used for furniture making and construction is increasing in many countries, and cause dust, endotoxin and formaldehyde exposure of the workers. The aim of the study was to assess the prevalence of respiratory symptoms and to measure lung function among Ethiopian particleboard workers using Eucalyptus trees as the raw material. In total 147 workers, 74 from particleboard production and 73 controls, participated in the study. Mean wood dust in the particleboard factories was measured to be above recommended limit values. Particleboard workers had a mean age of 28 years and the controls were 25 years. They had been working for 4 and 2 years, respectively. Lung function test was done using spirometry following American Thoracic Society (ATS) recommendations. Respiratory symptoms were collected using a standard questionnaire of ATS. Particleboard workers had higher prevalence of wheezing, cough, cough with sputum production, phlegm, and shortness of breath compared to controls. Lung function status was similar in the two groups. The symptoms might be related to the work in the factories. Longitudinal studies are recommended to explore the chronic impact of work in particleboard factories on respiratory health.

Knowledge, attitude and practice related to chemical hazards and personal protective equipment among particleboard workers in Ethiopia: a cross-sectional study

BACKGROUND

Work in the wood industry is often associated with exposure to wood dust and formaldehyde. The aims of this study were to describe the Knowledge, Attitude and Practice (KAP) concerning chemical health hazards among particleboard workers and to compare the KAP among temporary and permanent workers.

METHODS

A cross-sectional study design was used to collect data by structured questionnaires in two particleboard factories in Ethiopia. A total of 159 workers and 13 management personnel participated in this study. Both closed-ended and open-ended questions were included in the interviews. Chi-square tests, T tests and correlation analyses were used for categorical and continuous data. Total knowledge score (range 0-8) was calculated as the sum score of 8 items weighing one point each. Multiple linear regression was applied to estimate the impact of employment status on total knowledge score adjusted for level of education. Content analysis was applied to analyse collected data from open-ended questions.

RESULTS

The mean age of the respondents was 28 (SD = 6) years and on average they had 3.7 [3] years of service. The permanent workers were older than the temporary workers (29 vs 26 years, p = 0.001), and a considerably high fraction of the permanent workers had vocational education (90%) compared to the temporary workers (11%). Permanent workers had higher proportion of response on knowledge of 10 of 12 topics regarding chemical hazards and attitudes on 6 of 11 of these topics than temporary workers. Permanent workers had higher knowledge scores (3.7) compared to temporary workers (1.3) (p < 0.001), also after adjusting for education (p = 0.011). Permanent workers were provided with personal protective equipment (PPE) while temporary workers were not. The qualitative data helps to understand the workers and administrative personnel attitude and thinking regarding chemical hazards and PPE.

CONCLUSIONS

The findings revealed that permanent workers have higher proportion of positive response on knowledge and attitude towards chemical health hazards than temporary workers. However, practice in use of PPE depended on access to PPE. Few temporary workers were provided with PPE.

Occupational exposure to wood dust and risk of nasopharyngeal cancer: A systematic review and meta-analysis

INTRODUCTION

Nasopharyngeal cancer (NPC) is one of the most commonly occurring cancers in some regions. While wood dust is a confirmed human carcinogen, its association with NPC remains uncertain due to inconsistent findings in the related studies. We performed the first systematic review and meta-analysis on the epidemiological evidence to examine the association between occupational exposure to wood dust and the risk of NPC.

METHODS

In this meta-analysis study, the PubMed and Scopus databases were searched for English-language publications. seven case-control studies were included in the pooled analysis.

RESULTS

These studies were published between 1991 and 2016. The heterogeneity across the studies was significant (P = 0.06, I² = 50.4%). The results of the random effects model meta-analysis showed that there was a direct relationship between occupational exposure to wood dust and NPC (OR = 1.5 95% CI: 1.09-2.07). Among different histological subtypes of NPC, there was a significantly increased risk for the nonkeratinizing carcinoma following wood dust exposure (OR = 1.68, 95%CI: 1.03-2.74). We found no evidence of publication bias across studies according to the result of the Egger's test (P of bias = 0.073).

CONCLUSIONS

This meta-analysis suggests that occupational exposure to wood dust can be associated with an increased risk of the nonkeratinizing carcinoma of the histological subtypes of nasopharyngeal cancer.

Factors Affecting Lung Function: A Review of the Literature

Lung function reference values are traditionally based on anthropometric factors, such as weight, height, sex, and age. FVC and FEV₁ decline with age, while volumes and capacities, such as RV and FRC, increase. TLC, VC, RV, FVC and FEV₁ are affected by height, since they are proportional to body size. This means that a tall individual will experience greater decrease in lung volumes as they get older. Some variables, such as FRC and ERV, decline exponentially with an increase in weight, to the extent that tidal volume in morbidly obese patients can be close to that of RV. Men have longer airways than women, causing greater specific resistance in the respiratory tract. The increased work of breathing to increase ventilation among women means that their consumption of oxygen is higher than men under similar conditions of physical intensity. Lung volumes are higher when the subject is standing than in other positions. DLCO is significantly higher in supine positions than in sitting or standing positions, but the difference between sitting and standing positions is not significant. Anthropometric characteristics are insufficient to explain differences in lung function between different ethnic groups, underlining the importance of considering other factors in addition to the conventional anthropometric measurements.