Indian Journal of Clinical Anatomy and Physiology


Effect of occupational exposure to dust on pulmonary function tests in individuals working in saw mills in Raichur district


Full Text PDF



Author Details: Praveen Patil*,K Vijay Krishna

Volume : 6

Issue : 1

Online ISSN : 2394-2126

Print ISSN : 2394-2118

Article First Page : 77

Article End Page : 80


Abstract

Introduction: In general, Exposure to dust at working places causes deterioration of pulmonary functions, increased prevalence of respiratory diseases, worsening of existing illnesses and also increased incidences of cancer and deaths. There are many saw mills situated in Raichur district of Karnataka and many workers are engaged in working at saw mills. They are exposed to saw dust during there working hours. So the present study was taken up to evaluate the effect of wood dust exposure on pulmonary functions of these individuals and also to know the additive effect of smoking on respiratory health of these individuals.

Aim: To estimate the effect of saw dust exposure on PFT of saw mill workers. To compare the effect of saw dust exposure on PFT of smokers and non-smokers among saw mill workers.

Materials and Methods: Data collection was effected by way of an interviewer-administered, questionnaire to determine years of exposure as from date of employment, site or position at workplace, use of safety gadgets such as dust masks and earplugs to prevent entry of airborne microorganisms and dust into the mouth, nose and ear which can cause infections, etc. All the male workers in saw mills of age between 20-50 years were included. Results were expressed as Mean ± SD and Statistical comparison of measured variables between the 2 groups was carried out using unpaired-t-test and difference among mean values were calculated at a level of P<0>

Results: A significant difference in FVC, FEV1, FEV1/FVC ratio between saw mill workers and control group was found. We have also found a marked decrease (P<0>1 andFEV1/FVC ratio of smokers in comparison with non-smokers.

Conclusion: It is concluded from our study that exposure to saw dust causes inflammation which leads to decrease in lung compliance. Lesser compliance causes declined PFT values. A decrease in FVC in present study is an indication of restrictive lung disease conditions and decreased FEV1/FVC ration indication of Obstructive lung diseases.

Keywords: FVC, FEV1, FEV1/FVC ratio, Lung compliance, Obstructive lung diseases, PFT, Saw Mill, Smokers.

Introduction

In general, “Exposure to dust at working places causes deterioration of pulmonary functions, increased prevalence of respiratory diseases, worsening of existing illnesses and also increased incidences of cancer and deaths”.[1][2][3][4][5][6][7] Human health may be significantly affected by various organic and inorganic chemical substances, toxins and microorganisms present in wood dust.[8][9][10] It is also observed that throat irritation, oral cavity irritation, congestion in chest, dermatitis, urticaria, inflammation of alveoli, decreased pulmonary functions with reduced Forced Expiratory Volume (FEV1) may caused by these substances. These symptoms are observed when the dust exposure level exceeds higher than 5 mg/m3.[3][10][11][12][13][14][15][16] United States National Institute of Occupational Health and Safety (NIOSH) recommend that wood dust concentration should not exceed 1 mg/m[3] in the working atmosphere for a 8-hour working period.[17]The pulmonary function test is most important measure to assess lung functioning and efficiency. Measurement of dynamic lung functions is more important than that of static lung volumes. In respiratory diseases related to occupation, Spirometry plays a significant role in the diagnosis and prognosis of these diseases and is one of the most important diagnostic tools which describes the effect of restriction or obstruction on the lung function.[18][19]

 Disabilities and work related disorders are the major complaints in saw mill worker population. The respirable dust (<10>[20]

Community based studies have demonstrated that occupational exposure to dust or gases cause increased relative risks for respiratory symptoms consistent with chronic obstructive pulmonary disease (COPD) as well as for excess annual declines in Forced Expiratory Volume in one second (FEV1).[21]

A research study on sawmill workers concluded that due to saw dust exposure a significant reduction in FEV1, expiratory flow rate and forced vital capacity in saw mill workers as compared to controls.[22][23] Pulmonary obstruction, emphysema, pleural effusion, pneumothorax, pulmonary edema and poliomyelitis are being a pathophysiological aspects of a drop in the lung function parameters.[24] Similarly, the forced expiratory volume in first second reduced in obstructive lung diseases due to increased airway resistance during expiration and in restrictive lung diseases lung volumes are reduced due to decreased compliance of the lungs.[25] The decline in FEV1 is a convenient standard against which we can measure marked declines in subjects with the history of chronic obstructive pulmonary disease (COPD) or in subject exposed to environmental pollutants.[26]

Many studies have also elaborated the effect of smoking on respiratory illness in association with occupational dust exposure. A study conducted by Laraqui et al[27]on carpenters proved that smoking was significantly associated with symptoms of respiratory illness. Another study conducted by Marcuccilli et al[28] noted that besides occupational exposure to wood, tobacco had an influence on the occurrence of cough and expectoration. All the above research results suggest the fact that more often lung function impairments is related to a synergistic effect between tobacco and wood dust and not a separate impact of only one.

There are many saw mills situated in Raichur district of Karnataka and many workers are engaged in working at saw mills. They are exposed to saw dust during there working hours. So the present study has been uptaken to evaluate the effect of wood dust exposure on pulmonary functions of these individuals and also to know the additive effect of smoking on respiratory health of these individuals.

Objectives

  1. To estimate the effect of saw dust exposure on PFT of saw mill workers
  2. To compare the effect of saw dust exposure on PFT of smokers and non smokers among saw mill workers

Materials and Methods

Duration of the Study: Four months (April to July-2016).

It is a Cross Sectional Study, the samples were obtained by Simple Random Sampling method. The study was conducted on saw mill workers at Raichur district in Karnataka. The Ethical Clearance Certificate was obtained by Institutional Ethical Clearance Committee and also written informed consent was obtained by all the volunteers.

A total of 60 individuals working in saw mills for more than 5 years were selected for the study.

Data collection were effected by way of questionnaire to determine exposure duration, site or position at workplace, usage of safety gadgets like dust masks and earplugs, etc., Information on general health, history of past diseases and habits such as smoking and alcohol consumption from last 1 year were obtained.

Inclusion Criteria: All the workers in saw mills of age between 20-50 years were included.

Exclusion Criteria: Individuals having cardiorespiratory diseases before entering into the occupation were excluded. Individuals aged below 20 years and above 50 years were excluded from the study. Female individuals were not included in the study due to unavailability.

ATS reference Values consider for obstructive and restrictive lung diseases.

Obstructive Lung Diseases

  1. Mild: Predicted FEV1 <100>
  2. Moderate: Predicted FEV1 <70>
  3. Moderately severe: Predicted FEV1 <60>
  4. Severe: Predicted FEV1 <50>

Restrictive Lung Diseases

A reduction in the VC without a reduction of the FEV1/FVC ratio as a restriction of the volume excursion of the lung.

  1. Mild: Predicted TLC < lower>
  2. Moderate: Predicted TLC <70>
  3. Moderately severe: Predicted TLC <60>

Statistical Analysis

Results will be expressed as Mean ± SD and Statistical comparison of measured variables between the 2 groups will be carried out using unpaired-t-test and difference among mean values will be calculated at a level of P<0>

Results

Table 1: Anthropometric parameters of saw mill workers and control group

Parameters

Saw Mill Workers

Control Group

Height(cms)

166.75±4.13

167.3±3.92

Weight(kgs)

66.43±9.25

64.76±8.94

Age(years)

33.4±5.28

33.38±5.73

Note: cms- centimeters, kgs- kilograms.

Table 2: Comparison between Mean± SD of pulmonary function tests of saw mill workers and control group

Parameters

Mean± SD of Saw Mill Workers

Mean± SD of Control Group

P- Value

FVC (ltrs)

3.0±0.49

3.3±0.31

0.0002*

FEV1 (ltrs)

2.1±0.60

2.7±0.34

0.0001*

FEV1/FVC ratio (%)

70±14.0

81±6.1

0.0001*

Note: FVC- Forced Vital Capacity, FEV- Forced Expiratory Volume, *- Significant, NS- Non significant.

 Table 2, shows Mean± SD of saw mill workers and control group. There are significant differences (P<0>1, FEV1/FVC ratio between Saw mill workers and Control groups.

Table 3: Comparison between Mean± SD of pulmonary function tests of smokers and non-smokers among saw mill workers

Parameters

Mean± SD of Smokers (N=26)

Mean± SD of Non-Smokers (N=34)

P- Value

FVC (ltrs)

2.9±0.52

3.0±0.46

0.4332NS

FEV1 (ltrs)

1.8±0.57

2.4±0.50

0.0001*

FEV1/FVC ratio (%)

60±14

78±7.7

0.0001*

Note: FVC- Forced Vital Capacity, FEV- Forced Expiratory Volume, *- Significant, NS- Non significant.

Table 3 Depicts the Mean± SD of FVC. FEV1, FEV1/FVC ratio of smokers and non-smokers among saw mill workers. There was no significant difference (P>0.05) obtained in FVC between smokers and non-smokers,

significant differences obtained in FEV1 and FEV1/FVC ratio between smokers and non-smokers among saw mill workers.

Table 4: One-Way ANOVA of pulmonary function tests of smokers, non-smokers and control group

Parameters

Mean± SD of Control (N=60)

Mean± SD of Smokers (N=26)

Mean± SD of Non-Smokers (N=34)

P- Value

FVC (ltrs)

3.3±0.31

2.9±0.52

3.0±0.46

0.0001*

FEV1 (ltrs)

2.7±0.34

1.8±0.57

2.4±0.50

0.0001*

FEV1/FVC ratio

81±6.1

60±14

78±7.7

0.0001*

Note: FVC- Forced Vital Capacity, FEV- Forced Expiratory Volume, *- Significant, NS- Non significant.

In table 4, One-Way ANOVA for PFTs showing the significant differences (P<0>

Discussion

In our study we have found a significant difference in FVC, FEV1, FEV1/FVC ratio between saw mill workers and control group (Table 2). Similar study was carried out by few researchers, they found decline in FVC, and FEV1 with prolonged exposure to saw dust at workplaces.[29]

In the present study we have also found a marked decrease(P<0>1 and FEV1/FVC ratio of smokers in comparison with non-smokers (Table 3), which indicates the added adverse effect of smoking on respiratory functions of saw mill workers who are smokers. Our study is in agreement with the results obtained by Patrick A. Hessel et al, They proposed that the significant differences in lung function were seen most strongly in smokers among sawmill workers, it is possible that smoking and occupational exposures in the sawmill are interactive.[30] Entry of particulate matter into the airways and lungs lead to increased oxidant levels and inflammatory reactions. These inflammatory reactions lead to increased oxidative stress and inflammation, increased constriction of airways and decrease in elasticity of lung tissues. Resultantly, increased airway resistance and loss of lung compliance cause decrease in forced vital capacity and forced expiratory volume.

Conclusion

It is concluded from our study that chronic exposure to saw dust causes inflammation which leads to decrease in lung compliance. Lesser compliance causes declined PFT values. A decrease in FVC in present study is an indication of restrictive lung disease conditions and decreased

FEV1/FVC ration indication of Obstructive lung diseases. By the present study it is also concluded that cigarette smoking is one of the major additive factor for lung abnormality in sawmill workers, it fastens the deterioration of lung tissues and elasticity of lungs. It is recommended that saw mill workers must use masks and glove at their work places and also they must undergo routine lung function testing.

Limitations

Female individuals were not included in the study, in the present study molecular level testing was not carried out to know the molecular basis of the decreased lung compliance.

Implications

 This study indicates the health hazards of sawmill workers. Present study results can be taken as references for the further extended studies on mill workers. The results of present study implicate the effects of saw dust, cigarette smoke and interaction of saw dust particles with cigarette smoke particles, which can be prospectively studied at molecular levels.

Acknowledgement

We are very thankful to saw mill workers for participating in our research work. We also extend our regards to all the people who have helped us in carrying the present research work.

Conflict of Interest: None.

References

  1. ^ World Health Organization, International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Wood Dust and Formaldehyde. WHO 1997.
  2. ^ U.S. Department of Health and Human Services, Public Health Service National Toxicology Program. Final Report on Carcinogens Background Document for Wood Dust. Department 2000.
  3. a, b, c Schlünssen V, Schaumburg I, Andersen NT, Sigsgaard T, Pedersen OF. Nasal Patency is related to Dust Exposure in Wood-workers. Occup Environ Med 2002;59:23–29.
  4. ^ Demers PA, Teschke K, Kennedy SM. What to Do About Softwood? A Review of Respiratory Effects and Recommendations Regarding Exposure Limits. Am J Ind Med 1997;31:385–398.
  5. ^ Cormier Y, Merlaux A, Duchaine C. Respiratory Health Impact of Working in Sawmills in Eastern Canada. Arch Environ Health 2000;55(6):424–430.
  6. ^ Demers PA, Stellman SD, Colin D, Boffetta P. Non-malignant Respiratory Disease Mortality among Woodworkers Participating in the American Cancer Society Cancer Prevention StudyII (CPS-II). Am J Ind Med 1998;34:238–243.
  7. ^ Jeanne Magaer Stellman, Michael MacCann, Leon Warshaw, Carole Brabant, Editors. Psychosocial and Organizational Factors. Encyclopaedia of Occupational Health and Safety.4th ed. Vol II. Geneva: International Labour Office; 1998. p. 2–34.
  8. ^ Mandryk J, Alwis KU, Hocking AD. Work Related Symptoms and Dose Response Relationships for Personal Exposures and Pulmonary Function among Woodworkers. Am J Ind Med 1999; 5:481–490.
  9. ^ Douwes J, McLean D, Slater T, Pearce N. Asthma and Other Respiratory Symptoms in New Zealand Pine Processing Saw-mill Workers. Am J Ind Med 2001;8:608–615.
  10. a, b Edman K, Löfstedt H, Berg P, Erıksson K, Axelsson S, Bryngelsson I, et al. Exposure Assessment to α and β-Pinene, γ3-Carene and Wood Dust in Industrial Production of Wood Pellets. Ann Occup Hyg 2003;47(3):219–226.
  11. ^ Alwis KU, Mandryk J, Hocking AD. Exposure to Biohazards in Wood Dust: Bacteria, Fungi, Endotoxins, and (1→3)-β-D-Glucans. Occup Environ Hyg 1999;14(9):598–608.
  12. ^ Chung KYK, Cuthbert J, Revell GS, Wassel SG, Sum-mers N. A Study on Dust Emission, Particle Size Distribution and Formaldehyde Concentration during Machining of Medium Density Fibreboard. Ann Occup Hyg 2000;44(6):455–466.
  13. ^ Hursthouse A, Allen F, Rowley L, Smith F. A Pilot Study of Personnel Exposure to Respirable and Inhalable dust during the Sanding and Sawing of Medium Density Fi-breboard (MDF) and Soft Wood. Int J Environ Health Res 2004;14(4):323–326.
  14. ^ Priha E, Pennanen S, Rantio T, Uitti J, Liesivuori J. Exposure to and Acute Effects of Medium Density Fiber Board Dust. J Occup Environ Hyg 2004;1:738–744.
  15. ^ Schlünssen V, Schaumburg I, Taudorf E, Mikkelsen AB, Sigsgaard T. Respiratory Symptoms and Lung Function among Danish Woodworkers. J Occup Environ Med 2002;44:82–98.
  16. ^ Alwis KU. Occupational Exposure to Wood Dust. Department of Public Health and Community Medicine Faculty of Medicine the University of Sydney, New South Wales, Australia 1998.
  17. ^ McCammon C. NIOSH Health Hazard Evaluation Report 93-700. 1993.
  18. ^ Cotes JE. Lung function: Assessment and Application in Medicine. 5th ed. Oxford; Boston: Blackwell Scientific Publications 1993.
  19. ^ Wagner NL, Beckett WS, Steinberg R. Using spirometry results in occupational medicine and research. Common errors and good practice in statistical analysis and reporting. Indian J Occup Environ Med 2006;10(1):5-10.
  20. ^ Godleski J, Godleski JJ, Verrier RL, Koutrakis P, Catalano P, Coull B. Mechanisms of morbidity and mortality from exposure to ambient air particles. Res Rep Health Eff Inst 2000;915:88–103..
  21. ^ Mohamed E, A. Dalia. Occupational exposures as a cause of chronic obstructive pulmonary disease. Egypt J Bronchol 2009;3(1):11-23.
  22. ^ Bhat MR, Ramaswamy C: A comparative study of lung functions in rice mill and saw mill workers, Indian J Physiol Pharmacol 1991;35(1):27-30.
  23. ^ Erdinc Osman and Kayihan Pala, Occupational exposure to wood dust and health effects on the respiratory system in a minor industrial estate in bursa/turkey, Int J Occup Med Environ Health 2009;22(1):43–50.
  24. ^ Meo SA. Dose Responses of Years of Exposure on Lung Function In flour Mill Workers. J Occup Health 2004;46:187–191.
  25. ^ Keele CA, Neil E, Joles N, Editors. Respiration. In: Samson Wright’s Applied Physiology. 13th Ed. New York: Butter and Tanner Ltd.; 1982.
  26. ^ Mann CV, Russell RCG, Williams WS. Bailey and Loves, Short Practice of Surgery. 22nd Ed. London: Chapman and Hall; 1995..
  27. ^ Laraqui Hossini CH, Laraqui Hossini O, Rahhali AE, Verger C, Tripodi D. Respiratory risk in carpenters and cabinet makers. Rev Mal Respir 2002;18:615-622.
  28. ^ Marcuccilli A, Perdrix A, Metras E. Evaluation of symptoms and respiratory functions in relation to wood dust exposure in joinery workshops. Arch Occup Dis 1998;59:305-314.
  29. ^ Anupriya Deshpande. Effect of Chronic Exposure to Sawdust in Workers Employed in Saw Mills: A Cross- Sectional Study. Sch J App Med Sci 2004;2(4A):1202-1205.
  30. ^ Patrick A. Hessel. Lung Health in Sawmill Workers Exposed to Pine and Spruce. Chest J 1995;108(3):642-646.