RESPIRATORY SYMPTOMS AMONG FARMERS IN THE VICINITY OF A NORTH INDIAN CITY

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1 Original Article RESPIRATORY SYMPTOMS AMONG FARMERS IN THE VICINITY OF A NORTH INDIAN CITY D. Behera 1, Dharam Pal 2, D. Gupta 3 ABSTRACT Exposure to various types of farming occupation is associated with a number of respiratory problems which are both immunologic and non-immunologic in orgin. This study was undertaken to determine the prevalence of various respiratory symptoms and assess pulmonary function among farmers around the city of Chandigarh. An attempt was also made to identify the types of farming that may be associated with these symptoms. A house-to-house survey was carried out in seven villages around Chandigarh with the help of a questionnaire that was used in our earlier surveys. Lung function tests were carried Key Words : Farmers, Chronic bronchitis, cough, spirometry. out using a portable spirometer. Out of the 486 farmers included in the study, 106(21.8%) were symptomatic: chronic bronchitis (n=34), cough (n=38), bronchial asthma (n=13), post nasal drip (n=9), chest tightness (n=8) and dyspnea (n=4). The respiratory symptoms were more common among non-smokers (55.6%) than smokers (44.3%). Combined type of farming work was associated most often with respiratory symptoms followed by grain cutting. Pulmonary function parameters had lower values in smokers than in non-smokers and in symptomatic than in asymptomatic sybjects. Lung India 2005; 22 : INTRODUCTION A large proportion of farmers experience respiratory (e.g., cough with expectoration, chest tightness, sneezing, throat pain and wheezing) and/or systemic complaints (e.g. fever, muscle aches, headache) when exposed to farming environment 1. They usually experience symptoms within a few hours of working. It has been reported that the respiratory symptoms among farmers are usually not due to immunologic reactions 2. The action of grain dust appears to be independent of the complement pathway or cell cytotoxicity. Inhalation of dust, especially the grain dust, has been shown to cause release of histamine and leukotrienes from human lung tissues by a non-immunological mechanism. This mechanism has been suspected as the cause of acute bronchoconstriction in some farmers, and occurs immediately after exposure to antigens. Symptoms of chronic bronchitis have been reported to be more frequent among farmers as compared to a non-farming population and bronchial obstruction has also been found to occur more frequently than expected. A high prevalence of bronchial asthma has been reported among farmers the predominant cause likely being storage mites 3. For symptoms such as breathlessness, cough without any expectoration and wheezing, both smoking and animals rearing have been identified as the associated risk factors. Farming environment is 1 Professor, 2 Senior Resident, 3 Additional Professor, Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh Correspondence : Dr. D. Behera, Professor, Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh dbehera@glide.net.in Received September 2004, Accepted November also conducive to the development of occupational asthma and hypersensitivity pneumonitis 4. The present study was carried out to assess the frequency of respiratory symptoms among the farming community around Chandigarh and to identify the possible risk factors involved in it. MATERIAL AND METHODS A house-to-house survey was conducted in seven villages around Chandigarh and 486 farmers were included. Total number of houses covered was 216. The targeted farming population was 500. Those already diagnosed to have diabetes mellitus, hypertension, tuberculosis or any systemic illnesses were excluded from the study. These villages are situated within a distance of 3-5 km away from the city. A questionnaire developed on the pattern of BMRC with modifications and used in our earlier surveys 5 was used. The questionnaire contained questions on personal characteristics (name, age, sex, village and smoking habits) and type of farming (sowing, tilling, spraying of insecticides, cutting, grain handling, thrashing and grain storage). Questions on respiratory symptoms included: history of cough with or without any expectoration, amount of expectoration/day, winter exacerbations; history of hemoptysis and amount; history of any post nasal drip;

2 history of dyspnea on exertion; history of any wheezing with duration and any exacerbation on exposure to farming; history of chest tightness; and any systemic complaints (fever, headache and myalgia etc.). Chronic bronchitis was diagnosed if there was a history of cough with expectoration for at least three months in a year for two consecutive years. Bronchial asthma was diagnosed when there was history of recurrent cough with wheezing, associated allergy, clinical examination and reversibility with bronchodilator drugs. A thorough physical examination was done. Spirometry was carried out using a standard portable electronic spirometer (Micro medical instruments, Kent) and the following parameters were recorded: Forced vital capacity (FVC), Foreced expiratory volume in first second ( ) and Peak expiratory flow rate (PEFR). Each individual was explained how to perform the test and three readings were taken. The highest value of the three readings was recorded. The predicted values of each subject were calculated using regression equation from local population 6,7. The data was analysed using chi-square and student s t test. RESULTS There were a total of 486 farmers with 142(29.2%) being smokers (all males) and 344 (70.8%) non-smokers (214 males & 130 females). Out of 142 smokers, 94 were hooka smokers, 16 were smoking both bidi and cigaratte (Smoking index 144±12.0) and 32 were bidi smokers (smoking index 96±9,72). The age and sex distribution of the population studied was as follows: years - 18 males, 4 females; yrs-209 males, 92 females; >40 yrs-121 males, 42 females. Out of total 486 number of farmers studied, 106 (21.8%) were symptomatic with chronic bronchitis, cough, chest tightness, bronchial asthma, post nasal drip or dyspnea (Table 1). The respiratory symptoms were more common among non-smokers than in smokers (55.6% vs 44.3%, p<0.05. Combined type of farming work was associated most frequently with respiratory symptoms followed by cutting of crop (Table 2). Lung function parameters in smokers and nonsmoker subjects and those between symptomatic and asymptomatic individuals are shown in Table 3 and 4. The percentage predicted values of all the three parameters studied were less in smokers compared to nonsmokers. But even in nonsmokers, the values were less than 75% of the predicted. Similarly, the values of, FVC and PEFR in symptomatic farmers were less as compared to asymptomatic farmers, but even in the later, these were less than 75% of the predicted values. Table 1 : Distribution of the symptomatic group Symptoms Smoker* Nonsmoker* Total Male Female Male Female Chronic Bronchitis (32.1%) Cough (35.8%) Bronchial Asthma (12.3%) PND (8.5%) Chest Tightness (7.5%) Dyspnea (3.8%) 37(34.9%) 0(0%) 47(44.3%) 22(20.8%) 106(100%) *p<

3 Respiratory Symptoms among Farmers Table 2 : Relation between the occurrence of respiratory symptoms with type of farming Type of Farming Chronic Bronchial Cough PND Chest Dyspnea bronchitis asthma tightness S NS S NS S NS S NS S NS S NS Total Combined (66.0%) Cutting (14.1%) Tilling (6.6%) Sowing (4.7%) Grain (8.5%) handling S-Smokers, NS-Nonsmoker, PND-Post-nasal drip Table 3 : Comparison of pulmonary function test values among the smoker and non-smoker farmers Smoker (N=142) Non-Smoker (n=344) Parameters Means±SD %predicted Mean±SD %predicted FVC ±0.5** 2.02±0.6** (53.78%) (63.52%) FVC-P 3.52± ± ± ±0.6 (62.88%) 70.83%) -P 2.91±0.2* 2.64±0.4* PEFR ± ±109.0 (44.81%) (64.07%) PEFR-P 395.3± ±54.0 o-observed value; P-predicted value; FVC-L, =L, PEFR-L/min P<0.01 for all except* where p<0.05, and ** where p>0.05 Table 4: Comparison of pulmonary function test among symptomatic and asymptomatic farmers Symptomatic (n=106) Asymptomatic (n=380) Parameters Mean±SD % predicted Mean±SD %predicted FVC ±0.5** 2.07±0.6** (61.19%) (62.53%) FVC-P 3.17± ± ± ±0.6 (62.45%) (69.81%) -P 2.61± ±0.4 PEFR ± ±114.0 (54.82%) (59.09%) PEFR-P 360.6± ±52.0 P<0.01 for all except* where p<0.05, and ** where p>0.25 o-observed, p-predicted, FVC = L, = L. PEFR = L/min 47

4 DISCUSSION In this study, a total number of 486 farmers were studied, out of which 106 (21.8%) had symptoms of chronic bronchitis or bronchial asthma or complained of chest tightness, post nasal drip, dyspnoea and cough with prevalence rate of 21.8 percent. However, a study conducted among Danish farmers showed the prevalence of asthma was 7.7% and of chronic bronchitis was 23.6% in 1222 farmers 8. The prevalence of asthma and chronic bronchitis increased from 3.5% and 17.9% in years old farmers to 11.8% and 33.0% in year old farmers and from 5.5% and 17.5% in dairy farmers to 10.9% and 32.0% in pig farmers. Analysis with correction for age and smoking habits confirmed that pig farming was a risk factor for asthma, chronic bronchitis and wheezing during work. The prevalence of chronic bronchitis in this study is 6.9% and in Danish farmers it was 23.6%. The difference in the results could be due to different type of farming habits. Various types of respiratory symptoms in 22 non-smoking females partly may be related to domestic pollution due to use of cooking fuels (5). In the present study, 7.8% were having cough, which did not meet the criteria of chronic bronchitis or bronchial asthma. May be over the years they would be developing either chronic bronchitis or bronchial asthma. Thus, a total of 14.7% of the symptomatic farmers could be suffering from either chronic bronchitis or bronchial asthma. The prevalence of bronchial asthma in our study is 2.6% whereas it was 7.7% in Danish farmers which was in line with increased prevalence of bronchial asthma in European population. The respiratory symptoms were more common among the non-smoker farmers than in farmers who were smokers (69% vs 37%). Though smoking is an independent risk factor for chronic bronchitis, the possible reason for occurrence of symptoms more in nonsmoker than among the smoker could be attributed to occupational exposure. Similarly the prevalence of chronic bronchitis, bronchial asthma, post nasal drip, chest tightness & dyspnea were more in nonsmoker than among the smoker farmers, although that is not statistically significant. In an earlier study from North-Western India among 197 farmers, about 30% developed symptoms on exposure to wheat straw and vegetables 9. Their predominant symptoms comprised cough, malaise, dyspnoea and weakness. The overall prevalence of precipitating antibodies against clinically important thermophilic actinomycetes was 13.2%. On the basis of clinical and laboratory evaluation, 4 cases of farmer s lung were diagnosed and they showed improvement after receiving steroids. In the present study, we have not used serological tests, hence how many of the 106 will be having classical farmer s lung disease will be difficult to ascertain. We found that the combined type of farming is associated with increased occurrence of respiratory symptoms. Some of these farmers who were having chronic bronchitis or cough only might be due to extrinsic allergic alveolitis for which the serological tests were not done. Four of our subjects had dyspnoea only as the primary symptom wihtout any suggestion of bronchial asthma of chronic bronchitis. The pulmonary function test was normal in them. The cause of dyspnoea may be because of incipient COPD or underlying cardiac disease, which was not apparent clinically. The nose and throat examination was normal clinically in patients with post-nasal drip. The cause of chest tightness is difficult to explain. But it is a well-recognized symptom in bronchial asthma and restrictive lung diseases including Farmer s lung disease. The occurrence of various respiratory symptoms with types of farmings were not statistically significant although there was a good correlation with combined type of farming. Farmers are at increased risk of the development of respiratory symptoms compared with normal population 5,10. Spirometry values were reduced in symptomatic farmers than those without any symptoms. mean and PEFR wre reduced among those who do combined type of farming than those with cutting or sowing only. The percentage FVC is reduced in both smoker and non-smoker groups but it is more reduced in smokers group. Combined type of farming is associated with increased occurrence of respiratory symptoms, but pulmonary test abnormalities are not significant among the various types of farming groups. Only 22 females had different respiratory symptoms and indoor air pollution due to domestic cooking may be partly contributory to this. However, 48

5 Respiratory Symptoms among Farmers more number of non smoking males developing these symptoms could largely be due to factors associated with farming as they are not engaged with cooking and they stay indoors less often. Thus, the present study revealed occurrence of different respiratory symptoms amongst farmers. Lung function parameters are also affected in these subjects. In view of the fact that these symptoms are more frequent among nonsmokers than smokers, factors associated with farming, other than smoking alone may be contributory to such problems. References 1. Matson SC, Swanson MC, Reed CE, Yunginger JW. IgE and IgG mediated immune mechanisms don t mediate occupation related respiratory or systemic symptoms in hog farmers. J Allergy Clin Immunology 1983; 72: Donham KJ, Rubino M, Thedell TD, Kammermeyer J. Potential health hazards to agricultural workers in swine confinement buildings. J Occup Med 1977; 19: Van Haga Harmsten M, Johnsson SGO, Hoglund S, Tull P, wiren A, Zetterstorm O. Storage mite allergey is common in a farming population. Clin Allergy 1985;15: Dopico GA, Reddan W, Flaherty D, et al. Respiratory abnormalities among grain handlers, Am Rev Rspir Dis 1977; 115: Behera D, Jindal SK. Respiratory symptoms in women exposed to domestic cooking fuels. Chest 1991; 110: Malik SK, Jindal SK, Jindal VK. Vital capacity and forced expiratory volume, one second ( ) in normal healthy North Indian adults (I). Bull PGI1987; 21: Malik SK, Jindal SK, Jindal VK. Forced expiratory flow in normal healthy North Indian adults (II). Bull PGI1987; 21: Martin I, Ronald D. Respiratory symptoms in Danish farmers: An epidemiologically study of risk factors. Thorax 1988; 43: Gaur SN, Gangwar M, Khan ZU, Jain SK, Randhawa HS. Farmers lung disease in North Western India. Indian J Chest Dis Allied Sci 1992; 34: Malik SK. Profile of chronic bronchitis in North-India: The PGI experience ( ). Lung India 1986;4: