International Journal of Academic Medicine

: 2021  |  Volume : 7  |  Issue : 4  |  Page : 206--211

Respiratory morbidities among wood workers: An epidemiological study from the informal sector

Aritra Kumar Bose1, Dilip Dhaku Kadam2,  
1 Department of Community Medicine, T.N. Medical College and B.Y.L. Nair Hospital, Mumbai, India
2 Department of Community Medicine, Seth G.S. Medical College and KEM Hospital, Mumbai, India

Correspondence Address:
Dr. Dilip Dhaku Kadam
Aristo Bliss Apartment, Room No - 503, 5th Floor, Plot-15, Sector-27, Ranjanpada, Kharghar, Navi Mumbai - 410 210, Maharashtra


Introduction: Data on morbidities among workers working in the informal sector are scares; the current study attempts to determine the respiratory morbidities among wood workers and its severity. Materials and Methods: The study was a cross-sectional study conducted in the field practice area of a medical college's urban health center in a metropolitan city. One hundred and five wood workers from the study area were recruited by complete enumeration method. Data were collected using one to one interview method. Peak expiratory flow rate (PEFR) of every worker was measured using a peak expiratory flow meter. The data were analyzed using SPSS version 22. Results: Respiratory morbidities such as cough (61%), chest tightness (15.2%), and breathlessness (18.98%) were found among the workers. Nearly 68.56% of wood workers had abnormal PEFR. Decreased PEFR was significantly associated with lack of ventilation at the workplace, increased duration of work, use of electricity driven tools and tenure of the worker's job. Using logistic regression, we devised a model that shows abnormal PEFR is significantly dependent on work duration, hours of work per day, category of job, use of protective devices, and electrical instruments. Conclusions: The study pointed at a high prevalence of respiratory morbidities among wood workers. It also pointed out that the problem is in implementing occupational health standards already laid by international labor organizations (ILO). The following core competencies are addressed in this article: Medical knowledge, Patient care, Practice-based learning and improvement, Systems-based practice.

How to cite this article:
Bose AK, Kadam DD. Respiratory morbidities among wood workers: An epidemiological study from the informal sector.Int J Acad Med 2021;7:206-211

How to cite this URL:
Bose AK, Kadam DD. Respiratory morbidities among wood workers: An epidemiological study from the informal sector. Int J Acad Med [serial online] 2021 [cited 2022 Jan 18 ];7:206-211
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Occupational health is a branch of medicine that was once associated only with factories and mines. It has gradually evolved from a monodisciplinary risk-oriented activity to a multidisciplinary comprehensive approach embracing all employment types including mercantile, commercial enterprise, service trades, agriculture, and forestry. This has resulted in the expansion of the myriad of occupational diseases which man had ever known.

Respiratory diseases of occupational origin, also known as pneumoconiosis, are among the most common occupational diseases. They are caused due to long-term exposure to respirable dust. It has been documented that 10% of adult asthma cases are due to occupational dust exposure.[1] Worker working with wood is one such cadre who suffer from the ill effects of chronic exposure to dust. It is estimated that at least 2 million people are exposed to wood dust every day worldwide.[2] The adverse effects of exposure to wood dust include nasal carcinoma, allergic, irritant, cutaneous, and respiratory reactions and chronic respiratory impairment.

Atmospheric dust can be broadly categorized into two categories: (1) Respirable dust (<10 μm) and (2) nonrespirable dust (>10 μm). Wood dust is organic dust of <0.1 μm composed of cellulose, hemicelluloses, lignin, and hundreds of compounds known as “wood extractive.”[3] In cutting and sawing, wood dust consisting of fine particles of wood is released into the atmosphere. The main risk factor in the wood industry is this respirable wood dust.[4] When this fine dust enters the respiratory system to settle inside the bronchioles and alveoli, the human body initiates a foreign reaction to get rid of it initially causing lung irritation, mucus hypersecretion and cough. With continued exposure impairment of lung function, inflammation of the alveoli, airflow restriction, and finally, activity limitation.[5] This causes respiratory symptoms such as dry cough, breathlessness, chest tightness, and phlegm production etc.[2] The severity and rapidity of morbidity development are influenced by the composition of dust, the duration of exposure to dust, the concentration, and physical properties of airborne dust in the breathing zone.[6] Prolonged exposure to wood dust also causes chronic inflammation of the alveoli and bronchi, causing decreased air entry in the lungs, resulting in reduced lung function.[7]

The enumerated hazards become more severe in small industries, especially in the informal sector, where the workers' attention to working conditions is much down the priority list.[8] Studies have been conducted to find out the respiratory morbidities among carpenters around the world. Still, very few studies have tried to quantify the respiratory morbidities and their severity among the workers in the informal sector of India.


The aim of the study was to determine the socioepidemiological determinants of respiratory morbidities among wood workers.


To study the respiratory morbidities among wood workers and access its severity using a peak flow meterTo study epidemiological determinants of these respiratory morbiditiesTo recommend appropriate health promotional measures based on the study findings.


This was a cross-sectional study conducted in the field practice area of urban health center of a medical college in a metropolitan city. Ethical approval for conducting the research was obtained from the institutional ethics committee.

Study subjects

Based on preliminary inquiries and previous surveys conducted, the total number of workers in working in the area was 108. Three workers did not give consent to participate in the study, so all 105 workers were included in the study. They were working in 35 establishments in the study area. Individual visits were made to all workers. Informal discussions were done with them to build rapport. The study's purpose was explained using an informed consent document in a language they understand, and consent was obtained from each worker included in the study. A schedule for the interview was prepared in consultation with the woodworkers giving due consideration to the feasibility of their working hours and worker availability. One-to-one interview was conducted using a questionnaire which was validated by occupational health experts.

Study design

The respondents were enquired about preemployment training and use of personal protective equipment while working. The investigators assessed the lung function, i.e., peak expiratory flow rate (PEFR) by a multiuse handheld manual peak flow meter conforming to the European Union scale. Each subject was informed about the whole manoeuver, and they were encouraged to practice the manoeuver before doing the test. The test was repeated three times on each subject after adequate rest, and largest of the three values was taken as his PEFR of that particular person. The zone (green, yellow, and red), in which PEFR of the study subject lies was noted by the investigators. Confidentiality of the study subjects was maintained. Wood workers found to have any morbidities were referred to an appropriate health facility with a referral note.

Statistical analysis

Quantitative variables were presented as means ± standard deviation, while qualitative variables were expressed in terms of proportion. Descriptive and univariate analytic techniques were used to analyze the data. Categorical variables were compared employing Chi-square test and Fisher's exact tests, whereas continuous variables were compared using Student's t-test for independent observations. To study the joint effects and interactions of various independent variables, binary logistic regression analysis was carried out to calculate multivariate P value. All the analyses were performed using statistical software SPSS Version 23 (IBM SPSS Statistics for Windows, version 23 Armonk, NY, USA: IBM Corp.).


The study participants were all males belonging to the economically productive age group ranging from 18 to 58 years (n = 33.13 years). They were hailing from states of Uttar Pradesh (UP), Bihar, and Maharashtra. We found that 32.4% of subjects had studied till primary school and 34.3% till secondary school. The workers were predominantly Muslims belonging to lower socioeconomic class (52.4%) according to modified Kuppuswamy classification. The job profile of the workers was variable, 34 (32.4%) were cutters, 20 (19%) were polishers, 18 (17.1%) were helpers, 15 (14.3%) were freelancers, while 11 (10.5%) made designs on furniture's and 7 (6.7%) were owners of their workplaces. Approximately half of the workers were working in the field for <5 years (56%).

We found that majority of the workers were working more than 8 h a day with some even working 12 h/day without taking any breaks. They were also not allowed weekly offs. About 48 (45.7%) used electric and manually operated instruments, while 44 (41.9%) used hand-driven tools, and others used only electrically driven devices. Sixty-seven (63.08%) of the workers had an addiction including alcohol, cigarette, and tobacco chewing.

Study findings indicate that 68 (64.8%) of the workplaces had no ventilation, while only 20% had cross ventilation and 15.2% had exhaust ventilation. Most of the workplace floors were cleaned ones weekly. Cleaning of the floor was done by the woodworkers themselves using nonelectrical handheld equipment's. The respiratory morbidities experienced by the workers are enumerated in [Table 1].{Table 1}

When asked regarding personal protective devices, 60% of the workers answered in negative, while 40% who were using it, very few (35%) were using it regularly. The reasons for not using protective devices are enumerated in [Table 2].{Table 2}

The distribution of PEFR according to the job profile of the workers is presented in [Table 3].{Table 3}

On applying bivariate analysis using Chi-square test, it was found that the complaints of recurrent cough among the workers were significantly associated with the absence of ventilation at workplaces (P = 0.04). PEFR in the yellow and red zone (abnormal) was found to be significantly associated with work duration of more than 8 h (P = 0.04), absence of ventilation at workplaces (P = 0.03), and use of electricity operated tools (P = 0.028) by Chi-square test as illustrated in [Table 4].{Table 4}

On applying logistic regression after adjusting for age and height, we arrived at a model which shows that the average PEFR values of the workers are significantly influenced by the use of protective gears, the tenure of the job of the worker, type of instrument used, category of employment, and duration of work per day. The model explained 44.6% variance in average PEFR values and was able to identify 76.8% of the cases. The sensitivity and specificity of the model were 84.7% and 57.6%, respectively. The results show that, with each unit increase in job and work duration per day, the odds of having an abnormal PEFR value increase by 13.6 and 3.5 times, respectively. The odds of having an abnormal PEFR value if not using protective devices and electrical instruments are 0.39 and 1.43, respectively. Further as compared to owners, the odds of having an abnormal PEFR was 1.4 among cutters, 0.9 among design makers, 0.7 among helpers, and 0.4 among helper [Table 5].{Table 5}


In our study, most of the workers are migrants form states like UP, Bihar who have come to work in metropolitan cities to make a living. In an article by Singh, it is observed that migration from other states, mostly UP and Bihar, has increased over the past two decades.[9] Forced by poverty and in an attempt to save for their families workers are forced to work more than the working limits prescribed by factories act 1948.[10] We also found predominant use of electricity-driven tools by the workers. Electricity-driven devices eject fine dust in the atmosphere. When coupled with a poor working environment, lack of ventilation and irregular cleaning of floors can cause respiratory morbidities such as cough, breathlessness, and chest tightness. A study by Milanowski et al.[11] reported dry cough as the most common morbidity among furniture factory workers (52%). Similarly, Gómez et al.[12] in their study reported shortness of breath in 21.9% wood workers. Furthermore, lack of protective devices such as masks and hand gloves while working aggravates the respiratory morbidities. Similarly, Ezeugwu et al.,[13] in their study, reported that only 37.9% of the participants used protective devices while working. We found the lung functions of the majority of the workers were compromised. It was observed that the expiratory flow impairment was more in case of cutters, design makers, and helpers which may be due to direct and continuous exposure to wood dust. In their study, Whitehead et al.[14] found a significant association between wood dust exposure and reduced PEFR. Our study also found increased duration of work per day, lack of ventilation, use of electronic tools, and tenure of working in wood industry being significantly associated with decreased lung function which may be explained by the fact that all factors causing increase in dust concentration correlates with the decline in expiratory flow which may be detrimental to the life of the worker.


The employers must follow the minimum standards for woodworking recommended by ILO and Factories Act 1948. Basic essential requirements such as adequate space and ventilation must be provided in the workstations. These minimum necessities may be regularly monitored by shops and establishment department of Municipal Corporation. The electricity-driven equipment liberating suspended particulate matter in the air must be covered to reduce direct exposure to the dust. Cost-effective and straightforward methods such as regular cleaning of the workplace and wet moping before beginning work would decrease suspended dust. An urban health center may start an occupational health wing in collaboration with the occupational health department. This liaison will benefit all workers from organized and unorganized sectors in the nearby vicinity and help create awareness among the workers regarding the methods of prevention of respiratory diseases. This center may adapt the community-based camp approach to provide comprehensive health-care services to such workers to make them aware of the occupational hazards. The Prime Minister's health insurance scheme should be popularized among the wood workers to avail health facilities in government hospitals at no cost. The importance of proper segregation of wastes and its disposal in municipal dustbins should be stressed. Recycling of wood dust as a source of income may be popularized among wood workers. Equipment related to the monitoring of respiratory system such as peak flow meter, spirometer may be made available at the nearest UHC (study unit) and concerned physicians be trained to identify occupations related to morbidity concerning woodcraft. Services of chest physician may be made available at the UHC at least ones in 15 days.


This study needs to be considered in light of strengths and limitations. The limitation is only 105 wood workers who were working in the field practice area of urban health center could be included in the study, a larger sample would be required to generalize the study findings. Further the present study being a cross sectional study, can only be used to generate a hypothesis, further cohort studies can be undertaken to establish a causal relationship between dust concentration and the respiratory morbidities enumerated in the study. However, we are successful in quantifying the severity respiratory morbidities among workers of informal sector, which was the aim of the study.


The present study is one of India's firsts to study the respiratory morbidities in wood workers in informal sectors that were known till date. Results from this study provided insights into the high prevalence of respiratory morbidities among wood workers. It also pointed out that the problem is in the stage of implementation of standards. This calls for stringent monitoring and legislations to prevent bypassing the standards. The present study provided knowledge that helps take appropriate evidence-based actions to prevent morbidities and promote health of wood workers.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

Research quality and ethics statement

The authors of this manuscript declare that this scientific work complies with reporting quality, formatting, and reproducibility guidelines set forth by the EQUATOR Network. The authors also attest that this clinical investigation was determined to require Institutional Review Board/Ethics Committee review, and the corresponding protocol/approval number is EB34056R.


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