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Indian Journal of Community Medicine

Epidemological Study of Chronic Bronchitis Among Textile Workers In Pondicherry

Author(s): A.K. Mishra, S.B. Rotti, A. Sahai, M. Mohan, Danabalan

Vol. 29, No. 4 (2004-10 - 2004-12)

Abstract

Objectives: 1. To determine the prevalence of chronic bronchitis and other chronic respiratory illnesses among textile workers. 2. To identify the risk factors and to determine the risk associated with them. Design: Cross-sectional study.

Setting: One textile factory in Pondicherry.

Participants: Male textile workers.

Sample size: A sample of 800 out of 6000 workers.

Study variables: Age, smoking, presence of byssinsis, duration of service, worksites, overcrowding and fuel used for cooking.

Outcome variables: Chronic bronchitis.

Statistical analysis: Proportions, Chi Square Value, Logistic regression analysis with Odds ratio.

Results: Final study sample was 761, which consisted of 96 workers from the spinning section, 503 from the weaving section and 162 from the non-dusty sections. The common symptoms recognised included byssinosis (19.7%), chronic bronchitis (17%), cough with sputum (25%), breathlessness (20%) and chest tightness (10%) were common, it was noticed that 43% of the workers with chronic bronchitis had reduction of FEV1 (80%). Analysis showed that higher age (40 years or more), smoking and presence of byssinosis were significant risk factors for chronic bronchitis.

Conclusion: Cigarette/bidi smoking acts as a significant risk factor. Efforts need to be strengthened for further reduction of the concentration of dust and also cessation of smoking.

Key Words: Chronic bronchitis, cotton textile workers and smoking

Introduction

Cotton and synthetic textile industry in India is the largest industry in the country accounting for 20 percent of industrial output and providing employment to around 20 million workers1. The workers are at risk of suffering from various chronic respiratory illnesses including byssinosis, chronic bronchitis due to exposure to the cotton dust in the worksites. In a prospective study from Mumbai the prevalence of chronic bronchitis was reported to be 11-33 percent among individuals working in cotton textile mill with various types of cotton fibres2. In other study, it was found that the prevalence increased from 1.3 percent to 18 percent with prolongation in duration of exposure from less than 15 years to more than 40 years3. Even though quite a few studies have been conducted in textile mills in India, enough emphasis has not been given on the epidemiological aspects of chronic respiratory illnesses among the workers in these mills. In Pondicherry there are about 8,000 textile workers4. But no study whatsoever has been conducted in this area. Hence this study was undertaken to find out the epidemiological aspects of the chronic respiratory illnesses especially chronic bronchitis among textile mill workers with the objective to determine the prevalence of chronic bronchitis and other chronic respiratory illnesses among textile workers and to determine the risk of chronic bronchitis with regard to some biological and environmental factors.

Material and Methods

A cross-sectional-study was undertaken in the largest and the oldest textile factory in Pondicherry (Anglo-French Textiles). This factory comes under the administrative control of Pondicherry Textile Corporation. There are around 6,000 employees, working in three shifts in all the three units of the factory. 'A' unit is the oldest one having all the worksites including spinning, weaving, processing and other departments like engineering, transport, canteen etc. But 'B' unit is the recent one having only weaving and processing departments. 'C' unit is a canvas mill, which was not included in the study because of logistic reasons. Various techniques are being used for reducing the dust concentration in both 'A' and 'B' units. They have a well-maintained health clinic inside the factory premises, which is providing routine outpatient department services including emergency services and produce health checkups. The referral services including in-patient services are provided by the ESI Hospital, Pondicherry.

Permission was obtained from the factory administration before starting the study. An interview schedule was prepared with ATS-DLD-78 Questionnaire5 and Byssinosis Questionnaire6 as the basis and was pretested in a different factory (Swadeshi Cotton Mill) on 25 workers. The study period was from October 1998 to October 1999. From the sampling universe which consisted of 6,000 workers, a sampling frame was chosen covering only male workers of age 30 years and above with atleast 10 years of service in cotton mills. A sample of 800 workers was chosen by simple random technique proprotionate to the population of workers in the different sections of the factory. Health record of the workers selected for the study were screened for heart diseases with respiratory symptoms, chronic suppurative lung diseases and pulmonary tuberculosis. If anybody was found to have anyone of those conditions, he was excluded from the study.

Each worker, before being interviewed was explained on the confidentiality of information and the consent was taken. A working case defintion was evolved for "chronic bronchitis" as those having productive cough and sputum for 3 months or more than a year for 2 consecutive years or more. Those who had breathlessness and / or chest tightness on the first day of the week / on everyday of the week/ at work taken including the previous experience in other cotton factories, particularly in similar worksites. The study subjects were considered as heavy smokers if there was a current history of smoking 10 or more "cigarettes" or "bidis" per day for the last 20 years or more. Overcrowding was considered when the norms of rooms per person (1 room for 2 person, 2 rooms for 3 persons, 3 rooms for 5 persons....) were exceeded. The statistical analysis included means, proportions, standard deviations, chi-square test, relative risk and / or odd's Ratio, 95% confidence interval and the logistic regression (backward stepwise) analysis. All the analysis was done using Epi Info. 6 and SPSS (Statistical Package for Social Sciences) version 6.0 software.

Results

Out of the sample of 800 workers chosen for the study two workers died, five workers retired and 32 workers did not give consent for the study. Thus, final study sample was reduced to 761, which included 96 workers from the spinning section, 503 from the weaving section and 162 from the non-dusty sections. Majority of them were between 40 and 60 years of age. The mean age of the workers was 48 + 6.2 years. The height range of the workers was between 150 and 178 cm with an average of 169 + 6.9 cm. All the workers came under the same economic category, since almost all were drawing Rs. 5,000/- as basic pay per month. About one third (35.7%) of the workers were smokers and among them about 40% were found to be using 10 cigarettes/bidis per day for 20 years or more (20 pack years or more). Around two third of the workers had overcrowded housing enviornment. A regards the type of fuel used for cooking, about 50% were using gas as cooking fuel followed by kerosene (32%) and wood (18%). All the workers had a smoking experience ranging between 10 and 40 years, the mean duration being 27+6.4 years.

About two third of the workers had no respiratory symptoms. The prevalence of byssinosis was found to be 19.7% in the study population. The prevalence of chronic bronchitis was 17%. Other symptoms prevailing among the workers consisted of cough with sputum (25.1%), breathlessness (20%), chest tightness (10%) and sneezing (4%). In addition, it was found that most of the symptomatic workers had more than one symptom. FVC was found to be between 2.2 and 3.8 L with a mean of 2.6+0.36L. FEV1 was between 1.5 and 3.3 L with a mean of 2.2+0.34 L. PEFR was between 207 and 464 L/min. with mean of 338+65.3 L/min. In one eighty-five (18%) workers the ratio of FEV1 to FVC was less than 75%, indicating an obstructive lung pathology. Almost same proportion of workers was found to be between 75 and 80%, which is considered as normal. However, majority (63%) of the workers were having a ratio more than 80%. This included the healthy as well as those having restrictive lung pathology. It was seen that among the 130 workers with chronic bronchitis, 43% had FEV1 less than 80% of the predicted, whereas 71% had reduced PEFR by 10% or more. Only 16% workers with chronic bronchitis had FEV1 / FEC ratio less than normal (75-80%).

The univariate analysis of the factors showed that an age of 40 years or more, current smoking bronchitis (Table I). All the significant factors of the univariate analysis were included for the logistic regression analysis (backward stepwise). This showed that the risk was 7.6 times more for the workers with age of 40 years or more compared to those with age less than 40 years (95% CI - 1.9, 29.9). It was also found that the risk was 3.4 times higher with workers having symptomatic byssinosis compared to those without it (95% CI-2.2, 4.9). The workers, smoking currently were also found to have 2.8 times (95% CI - 1.8, 4.09) higher risk of development of chronic bronchitis (Table II).

Table I: Univariate Analysis of Factors Associated With Chronic Bronchitis.

Sr.
No.
Factors No.
Studied
%age with
chronic
bronchitis
X2
Value
RR
1. Age
  40 years or more 698 18.3 9.3 6.8* (1.6,28.3)
  <40 years 63 3.2     1
2. Smoking
  Smoker 272 26.5 26.3 2.7* (1.8, 3.9)
  Non-smokers 489 11.9     1
3. Duration of Service
  25 years or more 534 15.5 2.9 0.7 (0.4, 1.07)
  <25 years 227 20.7     1
4. Presence of byssinosis
  Present 150 32.0 29.3 3.03* (2.0, 4.6)
  Absent 611 13.4     1
5. Fuel use for cooking
  Wood+kerosene 397 18.1 0.6 1.2 (0.7, 1.7)
  Gas 364 15.9     1
6. Overcrowding
  Present 492 66.9 0.35 1.1 (0.7, 1.6)
  Absent 269 33.1     1
7. Worksites
  Spinning 96 30.2 2.7 1.6 (0.9, 2.9)
  Weaving 503 13.3 5.6 0.6 (0.4, 0.9)
  Non-dusty sections 162 21.0     1
(*p<0.05)

Table II: Logistic Regression Analysis of Significant Risk Factors Associated with Chronic Bronchitis

Risk.
Factors
No.
Studied
Chronic
Bronchitis
No. (%)
Odd's
Ratio
(95% CI)
Age
40 years or more 698 18.3 7.6(1.9, 29.9)        
< 40 years 63 3.2 1.00        
Presence of byssinosis
Present 150 32.0 3.4(2.2, 4.9)        
Absent 611 13.4 1.00        
Smoking
Smoker 272 26.5 2.8(1.8, 4.09)        
Non-smoker 489 11.9 1.00        

Discussion

Chronic bronchitis is a well-known disease entity of old age. The problem becomes grave in presence of other conditions, which have an irritant effect on the lung mucosa like smoking, other indoor and outdoor pollution and incriminate worksites. In our study the prevalence of chronic bronchitis was found to be 17%, which was comparable to 11-33% among cotton textile workers in Mumbai2. Similarly the prevalence was found to be 16% among textile mill workers in another Indian study3. In general, the higher age has been established as a risk factor for chronic bronchitis. In a study from UK, cotton textile workers with age over 45 years were more likely to suffer from chronic bronchitis. This was quite comparable to the findings of out study6,9.

Besides this, smoking was also found to be a significant risk factor. The prevalence of chronic bronchitis was 26.5% among smokers and 11.9% among non-smokers in the present study, which is quite comparable to the findings of an Indian study from Mumbai showing 19.5% and 3% among smokers and non-smokers of a cotton textile mill respectively8. Our findings regarding influence of smoking were very much similar to those reported by a study from Britain in which the prevalence was higher among smokers compared to non-smokers11.

Cotton textile workers suffer from a variety of respiratory diseases because of exposure to cotton dust. It has been clearly mentioned by Kamat et al that in Indian cotton textile workers byssinosis is quite distinct drom chronic bronchitis. But in our study it was seen that 32% of the workers with byssinosis had chronic bronchitis (p<0.01), which is similar to the finding of a study by Martin et al13. Various workers have reported that dusty sections like carding, ring frame, drawing, spinning etc. were found to be associated with higher prevalence of chronic bronchitis compared to the non-dusty sections8,10. Whereas in the present study, dusty worksites like spinning and weaving sections did not show any significant association with chronic bronchitis, which is similar to the finding of the study from Lodz12.

In our study there was no significant association with the duration of service, but some workers have reported that the prevalence of chronic bronchitis increased with increase in duration of service2,9. In the present study, it was noticed that there was no significant decrease in lung function parameters like FEV1, PEFR among those suffering from chronic bronchitis compared to those without the disease. But in a study from UK, chronic bronchitis was associated with a small but significant decrement in lung functions like FVC and percent predicted of FEV16.

Conclusion

It can be concluded that cigarette/bidi smoking acts as a significant risk factor for development of chronic bronchitis. Efforts should be strengthened for further reduction of dust concentration and cessation of smoking.

Acknowledgement

We are thankful to the factory administration of the Anglo-French Textile for their kind co-operation throughout the study and also to the workers of the factory for their active participation.

References

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  10. Awad el Karim MA, Usman Y, el Haimi YA. Byssinosis : environmental & respiratory symptoms among textile workers in Sudan. Int. Arch. Occup. Environ. Health. 1986, 57(2) : 101-8.
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1. Department of P.S.M., 2. Deptt. of Physiology, JIPMER, Pondicherry

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