Effect Of Cotton Dust Exposure On Respiratory Health Outcomes Among Textile Workers.

BACKGROUND: Cotton dust is generated during various textile manufacturing processes. Only a few studies from Pakistan assessed cotton dust exposure and explored the relationship of duration of work in the textile industry with respiratory health outcomes. We aimed to assess cotton dust exposure and its association with lung function and respiratory symptoms among textile workers in Pakistan. METHODS: We report findings from the baseline survey of the larger study, MultiTex, among 498 adult male textile workers from six mills conducted between October 2015-March 2016 in Karachi, Pakistan. Data collection included the use of standardized questionnaires; spirometry, and area dust measurements through UCB-PATS. Multivariable logistic and linear regression models were developed to assess the association of risk factors with respiratory symptoms and illnesses. RESULTS: We found the mean age of workers to be 32.5 (±10) years; around 25% were illiterate. The prevalence of COPD, asthma, and byssinosis was 10%, 17%, and 2%, respectively. The median cotton dust exposure was 0.33 mg/m3 (IQR: 0.12-0.76). Increased duration of work among non-smokers was associated with a decline in lung function, FVC (-245 ml; 95% CI: -385.71, -104.89) and FEV1 (-200 ml; 95% CI: -328.71, -841.1). Workers with certain job titles (machine operators, helpers, and jobbers), those with greater duration of work, and higher dust exposure, were more likely to report respiratory symptoms and illnesses. CONCLUSIONS: We report a high prevalence of asthma and COPD and a low prevalence of byssinosis. Cotton dust exposure and duration of employment were associated with respiratory health outcomes. Our findings highlight the need for preventive interventions in the textile industry in Pakistan.

Byssinosis and lung health among cotton textile workers: baseline findings of the MultiTex trial in Karachi, Pakistan.

OBJECTIVES: To assess the association of exposure in cotton mills in Karachi with different definitions of byssinosis and lung health. METHODS: This cross-sectional survey took place between June 2019 and October 2020 among 2031 workers across 38 spinning and weaving mills in Karachi. Data collection involved questionnaire-based interviews, spirometry and measurements of personal exposure to inhalable dust. Byssinosis was defined using both WHO symptoms-based (work-related chest tightness), and Schilling's criteria (symptoms with decreased forced expiratory volume in 1 s (FEV1). Values of FEV1/forced vital capacity ratio below the lower limit of normality on postbronchodilator test were considered as 'chronic airflow obstruction' (CAO). RESULTS: 56% of participants had at least one respiratory symptom, while 43% had shortness of breath (grade 1). Prevalence of byssinosis according to WHO criteria was 3%, it was 4% according to Schilling's criteria, and likewise for CAO. We found low inhalable dust exposures (geometric mean: 610 µg/m3). Cigarette smoking (≥3.5 pack-years), increasing duration of employment in the textile industry and work in the spinning section were important factors found to be associated with several respiratory outcomes. CONCLUSION: We found a high prevalence of respiratory symptoms but a low prevalence of byssinosis. Most respiratory outcomes were associated with duration of employment in textile industry. We have discussed the challenges faced in using current, standard guidelines for identifying byssinosis.

Health Concerns of Textile Workers and Associated Community.

BACKGROUND: Workers in the textile industry risk developing various respiratory and pulmonary diseases due to exposure to cotton dust. The particles from the cotton lint are inhaled by the workers and results in the breathing problems including asthma, shortness of breath, cough and tightness in the chest. The poor health of labor contributes to the low productivity of the labor and in serious cases loss of jobs leading to the poverty. OBJECTIVE: To assess the prevalence of respiratory symptoms among the textile workers and associated community. To contrast the health profiles of the textile workers, associated community and the control group to factor out any confounding factors. METHODS: This study explores the health profiles of the textile workers and associated community and contrast them against the health profile of the control group to factor out any confounding factors. The study is conducted on cotton industry in Kasur, Pakistan. We interviewed 207 workers, 226 people from associated community (living in vicinities of weaving units) and 188 people for control group (from areas far away from weaving units and people are not associated with weaving industry) based on stratified random sampling technique. We employed descriptive methods and logistic regression to explore the association between respiratory diseases and weaving workers. RESULTS: Overall, prevalence of postnasal drip, byssinosis, asthma, and chronic bronchitis were 47%, 35%, 20%, and 10%, respectively, among the workers. These percentages are significantly higher than the control group. An additional year of work increase the risk of postnasal drip, byssinosis, asthma, and chronic bronchitis by 5-6%. Among workers, 43% and 21% feel difficulty in hearing against noisy background and at low volume, respectively. Due to bad light arrangements at workstations, 21% and 31% workers are suffering from myopia and hyperopia, respectively. Proportions of the workers suffering from continuous headache, skin infection, depression, and low back pain are 28%, 29%, 27%, and 44%, respectively. Chi-square test results confirms that no confounding factor like air pollution is involved in this cause-and-effect study implying the association between the cotton dust and associated diseases is not spurious. CONCLUSION: Respiratory symptoms were statistically significantly more common in the weaving workers compared to control group. Better environment at workstations, use of protective gears and education are the factors which reduce the risk of associated diseases among workers.

Contemporary Prevalence of Byssinosis in Low- and Middle-Income Countries: A Systematic Review.

We aimed to identify the contemporary prevalence of byssinosis through a systematic review. Medline, Web of Science, Embase, and Global Health databases were used to identify studies published in any language between 2000 and 2019, reporting primary data on byssinosis among adults. We used the Joanna Briggs Institute checklist to estimate the risk of bias in studies and undertook a qualitative, narrative data analysis. The review considered the prevalence of byssinosis, chest tightness, and airflow obstruction in textile workers in low- and middle-income countries (LMICs). We found 26 relevant studies that included 6930 workers across 12 countries. Most of the studies (n = 19) were from Asia, and seven from African countries. Twenty-five studies were cross-sectional surveys while one was a cohort study. The prevalence of byssinosis was reported by 18 studies, and ranged from 8% to 38%, without any clear associations, at the group level, between the prevalence of byssinosis and durations of workers' exposures. Prevalence of chest tightness ranged between 4% and 58% and that of airflow obstruction between 10% and 30%. A strong correlation (r = 0.72) was found between prevalence of byssinosis and cotton dust levels. Our findings indicate that byssinosis remains a significant, contemporary problem in some parts of the textile sector in LMICs.

Epidemiology of respiratory diseases and associated factors among female textile workers in Pakistan.

Objective. The study aimed to estimate the prevalence of byssinosis and other respiratory symptoms among women textile workers and the associated risk factors in 18 spinning mills of Faisalabad and Lahore districts of Punjab, Pakistan. Method. In this case-control study of 1054 female workers, we used the dose-response function to measure the association between dust level and respiratory disorders in cotton textile workers. Results. Working overtime and long working hours per week are significantly associated with self-reported symptoms of byssinosis. Women's age, marital status and wages were significantly associated with mitigating actions (seeing the doctor), while the education of the women was significantly associated with averting action (use of a mask). Conclusion. Regulating working hours and ensuring employees' compliance with the safety standards are expected to mitigate the health problems of female workers.

Byssinosis and tuberculosis amongst "home-based" powerloom workers in Madhya Pradesh State, India.

BACKGROUND: Byssinosis is an occupational lung disease observed among workers exposed to cotton, flax, and hemp dust. The severity and extent of Byssinosis are well recognised in the high-income countries and control measures have been implemented to prevent the disease. In India, there are conflicting evidence on burden estimation of the disease, followed by inadequate prevention and control of Byssinosis. DESIGN/METHODS: We did a cross-sectional study to assess the prevalence of Byssinosis in "home-based" power-loom workers in Mominpura, an administrative ward of Burhanpur Municipality with 2800 population in the state of Madhya Pradesh, India. 290 adults working from "home-based" power loom units were randomly selected, profiled and screened for Byssinosis like symptoms with the help of a semi-structured questionnaire and simple hand-held peak expiratory flow monitor. For epidemiological purposes the symptoms were classified based on Schilling's classification. Chest x-rays were done for selected subjects. Sputum smear microscopy for detecting TB was done for those who had Byssinosis like symptoms. RESULTS: Prevalence of Byssinosis among "home based" powerloom workers was found to be 98% [n = 283, 95 CI (95.65-98.96)]. Peak expiratory flow rate (PEFR) was reduced in 44% (n = 124), of which 81 (29%) had more than 50% PEFR reduction, and of these, 69 (29%) were in early stage of Byssinosis (Grade 0.5). 11% of study participants who had Byssinosis like symptoms, also had TB. CONCLUSIONS: Byssinosis is highly prevalent in "home-based" power loom units in Madhya Pradesh. Adequate advocacy on awareness and prevention; prompt diagnosis and linkages to treatment services in "home-based" power loom units are urgently required to address Byssinosis at an early disease stage.

Byssinosis and COPD rates among factory workers manufacturing hemp and jute.

OBJECTIVES: Prior studies have been performed on cotton textile plants throughout the world. This study was planned to identify the rate of byssinosis and chronic obstructive pulmonary disease (COPD) in hemp and jute workers and those who worked with both of them. MATERIAL AND METHODS: The study was realized in a factory which consecutively processed hemp and jute. The study enrollment included 266 people, 164 of whom were active workers and 102 were retired. A questionnaire, plain chest X-rays, physical examination and pulmonary function tests were performed. Dust levels were measured in various sections of the factory during 8 h work shifts. Endotoxin levels of various quality hemp fibers and dusts were measured. RESULTS: The rate of byssinosis (28.2%) was higher among the workers that who exposed to both jute and hemp dust. The frequency of chronic bronchitis in retired workers who previously smoked was higher (20%) as compared to currently smoking workers (17%). High dust levels were measured in some parts of the factory (mean (M) = 2.69 mg/m3). Working in dense dust areas, active smoking, being older than 40 years of age, being an ex-smoker, and working in the factory for a period exceeding 15 years were significantly associated with bronchitis and emphysema development. High endotoxin levels were determined for fine hemp dust (605 EU/mg), coarse hemp dust (336 EU/mg) and poor quality hemp fibers (114 EU/mg), whereas in fresh hemp stalks the level of endotoxin was determined to be lower (0.27 EU/mg). CONCLUSIONS: Because of high exposures to jute and hemp dusts that are associated with high byssinosis rates, personal protection and environmental hygiene is crucial to prevention of byssinosis.

Metal fume fever and polymer fume fever.

INTRODUCTION: Inhalational exposure to metal-containing fumes generated by welding and related processes may result in the development of the clinical syndrome known as "metal fume fever." Polymer fume fever is a separate and distinct but related disorder that has been associated with inhalational exposure to specific fluorinated polymer products, such as polytetrafluoroethylene or Teflon(®). We undertook a review of the peer-reviewed medical literature as it relates to these two disease entities in order to describe their epidemiology, pathophysiology, clinical presentation, diagnosis, treatment, prevention, and prognosis. METHODOLOGY: We performed a search of the PubMed ( www.pubmed.com ) and Ovid MEDLINE (ovidsp.tx.ovid.com) databases for keywords "metal fume fever," "polymer fume fever," and "fume fever," covering the period 1946 to September 2014, which resulted in a total of 141 citations. Limiting the search to articles published in the English language yielded 115 citations. These 115 articles were manually reviewed for relevance. In addition, the reference lists in each article retrieved were reviewed for additional relevant references. This left 48 relevant citations. EPIDEMIOLOGY: Metal fume fever occurs most commonly as an occupational disease in individuals who perform welding and other metal-joining activities for a living. It is estimated that 1,500-2,500 cases of metal fume fever occur annually in the United States. Polymer fume fever was initially identified as an occupational disease but increased regulations have resulted in decreased incidence in the occupational setting. Overheating of Teflon(®)-coated cookware is one of the more common mechanisms for exposure. PATHOPHYSIOLOGY: While the precise pathophysiology associated with the development of metal fume fever is yet to be elucidated, suggested pathophysiologic mechanisms include pro-inflammatory cytokine release, neutrophil activation, and oxygen radical formation. The pathophysiologic mechanism for polymer fume fever has not been definitively elucidated but may involve similar mechanisms to those proposed for metal fume fever. CLINICAL PRESENTATION: Metal fume fever typically presents with generally non-specific complaints including influenza-like symptoms, fever, shaking chills, arthalgias, myalgias, headache, and malaise. Onset of symptoms typically occurs 4-10 h following the exposure to metal-containing fumes. While metal fume fever is typically benign and self-limited, severe cases of the disease have been reported. In patients with ongoing metal fume exposure over the course of a workweek, tachyphylaxis occurs resulting in improvement in symptoms over the course of the workweek and maximal symptoms occurring after an exposure-free period such as a weekend. The clinical presentation of polymer fume fever is indistinguishable from metal fume fever, with an exposure history being necessary to distinguish the two entities. DIAGNOSIS: Chest radiographs are typically normal in cases of metal fume fever and polymer fume fever; however, mild vascular congestion may be demonstrated and severe cases may feature diffuse patchy infiltrates. Laboratory studies are typically not necessary but may demonstrate leukocytosis with leftward shift or an elevated erythrocyte sedimentation rate. TREATMENT: The primary treatment for both metal fume fever and polymer fume fever is supportive and directed at symptom relief. Oral hydration, rest, and the use of antipyretics and anti-inflammatory medications (e.g., non-steroidal anti-inflammatory drugs and aspirin) are recommended. A careful workplace exposure assessment analysis conducted by an occupational medicine specialist or clinical toxicologist in concert with a qualified industrial hygienist should be performed. PREVENTION: A careful workplace exposure assessment including measurement of ambient zinc and other metal (e.g., chrome, nickel, copper and manganese) fume concentrations or concentrations of fluorocarbon polymer decomposition products at different locations within the workplace should be performed. PROGNOSIS: Metal fume fever is typically a benign and self-limited disease entity that resolves over 12-48 h following cessation of exposure. CONCLUSIONS: Metal and polymer fume fevers generally follow a benign course with spontaneous resolution of symptoms, though both have the potential to be serious, especially in those with significant preexisting cardiorespiratory disease.

The prevalence of byssinosis among cotton workers in the north of Benin.

BACKGROUND: Cotton is the main agricultural export product in Benin. Cotton dust is thus present in the air during the handling and processing of cotton. This dust contains a mixture of substances including ground up plant matter, fibres, bacteria, fungi, soil, pesticides, noncotton matter, and other contaminants. While cotton processing is decreasing in industrialized countries, it is increasing in developing countries. Cotton processing, particularly in the early processes of spinning, can cause byssinosis. OBJECTIVE: To determine the respiratory effects of cotton dust exposure among cotton mill workers in Benin. METHODS: In a cross-sectional study, 109 workers exposed to cotton dust and 107 unexposed workers were studied. The International Commission on Occupational Health (ICOH) questionnaire was used for data collection on respiratory symptoms. For each worker, crossshift pulmonary function was performed with a dry spirometer. Based on the severity of respiratory symptoms and spirometry byssinosis was defined and classified according to the criteria of Schilling, et al. RESULTS: The mean ± SD age of the exposed and unexposed workers was 46.3 ± 7.8 and 37.0 ± 8.3 years, respectively (p<0.001). The mean FEV1 predicted value for the exposed and unexposed workers was 76.3% and 77.3%, respectively. The prevalence of grade 3 byssinosis was 21.1% (95% CI: 13.4-28.9) in exposed workers and 8.4% (95% CI: 3.1-13.7) in unexposed workers (p=0.006). On Mondays, the exposed workers had more respiratory symptoms than unexposed workers; for grade 3 byssinosis, the prevalence was 13.8% in exposed and 4.7% in unexposed workers (p=0.011). CONCLUSION: The prevalence of respiratory symptoms and byssinosis among cotton mill workers in Benin is high and needs prompt attention of health care workers and policymakers.

Respiratory impairment in cotton-ginning workers exposed to cotton dust.

Dust generated during the handling and processing of cotton causes ill health of ginning workers. The purpose of this study was to determine the prevalence of respiratory symptoms among cotton-ginning workers. This study involved 188 workers of 10 cotton-ginning factories. Forced vital capacity (FVC), peak expiratory flow rate (PEFR), and forced expiratory volume in 1 s (FEV1) declined significantly with increasing duration of exposure (p < .001) of the cotton-ginning workers. Results of a standard respirator medical evaluation questionnaire indicated that, depending on duration of exposure, 51%-71% of cotton-ginning workers suffered from chest tightness, 55%-62% experienced chest pain, while 33%-42% of the workers reported frequent cough. Blood tests of the workers showed higher values of erythrocyte sedimentation rate, eosinophils, and white blood cells when exposure was longer. Byssinosis symptoms were observed among the workers. We recommend regular periodical medical check-ups, compulsory use of personal protective equipment, and proper ventilation at the workplace.

Monitoring of cotton dust and health risk assessment in small-scale weaving industry.

The present study describes the estimation of particulate matter (cotton dust) with different sizes, i.e., PM(1.0), PM(2.5), PM(4.0), and PM(10.0 µm) in small-scale weaving industry (power looms) situated in district Hafizabad, Punjab, Pakistan, and the assessment of health problems of workers associated with these pollutants. A significant difference was found in PM(1.0), PM(2.5), PM(4.0), and PM(10.0) with reference to nine different sampling stations with p values <0.05. Multiple comparisons of particulate matter with respect to size, i.e. PM(1.0), PM(2.5), PM(4.0), and PM(10.0), depict that PM(1.0) differs significantly from PM(2.5), PM(4.0), and PM(10.0), with p values <0.05 and that PM(2.5) differs significantly from PM(1.0) and PM(10.0), with p values <0.05, whereas PM(2.5) differs non-significantly from PM(4.0), with a p value >0.05 in defined sampling stations on an average basis. Majority of the workers were facing several diseases due to interaction with particulate matter (cotton dust) during working hours. Flue, cough, eye, and skin infections were the most common diseases among workers caused by particulate matter (cotton dust).

Chronic lung function decline in cotton textile workers: roles of historical and recent exposures to endotoxin.

BACKGROUND: Long-term occupational exposure to cotton dust that contains endotoxin is associated with chronic respiratory symptoms and excessive decline in forced expiratory volume in 1 sec (FEV1), but the mechanisms of endotoxin-related chronic airflow obstruction remain unclear. OBJECTIVE: In the current study, we examined temporal aspects of the exposure-response relationship between airborne endotoxin exposure, longitudinal change in FEV1, and respiratory symptoms in a cohort of Chinese cotton textile workers. METHODS: This prospective cohort study followed 447 cotton textile workers from 1981 to 2006. at approximately 5-year intervals. We used a generalized estimating equations approach to model FEV1 level and respiratory symptoms as a function of past exposure (cumulative exposure up to the start of the most recent 5-year survey interval) and cumulative exposure (within the most recent interval) to endotoxins, after adjusting for other covariates. Models were stratified by active versus retired work status and by years employed before the baseline survey (< 5 and > or = 5 years). RESULTS AND CONCLUSIONS: Past exposure to endotoxin was associated with reduced FEV1 level among retired cotton workers. Among all cotton workers, past exposure was more strongly associated with reduced FEV1 for those hired < 5 years before baseline than for those who were hired > or = 5 years after baseline. Recent endotoxin exposure was significantly associated with byssinosis, chronic bronchitis, and chronic cough.

Long-term effects of work cessation on respiratory health of textile workers: a 25-year follow-up study.

RATIONALE: The degree to which chronic respiratory health effects caused by exposures to cotton dust and endotoxin is reversible after cessation of textile work is unknown. OBJECTIVES: To investigate changes in lung function and respiratory symptoms after cessation of textile work and to determine whether past exposure to cotton dust and endotoxin or smoking history modify the associations. METHODS: We performed a prospective cohort study consisting of 447 cotton textile workers exposed to cotton dust and 472 unexposed silk textile workers, with a 25-year follow-up. Spirometry testing and respiratory questionnaires were conducted at 5-year intervals. Generalized estimated equations were used to model the average 5-year change in FEV(1) and odds ratios of respiratory symptom prevalence. MEASUREMENTS AND MAIN RESULTS: Years since cessation of textile work was positively associated with 11.3 ml/yr and 5.6 ml/yr gains in 5-year FEV(1) change for cotton and silk workers, respectively. Among male cotton workers, smokers gained more FEV(1) per year after cessation of exposure than did nonsmokers, and the risk of symptoms of chronic bronchitis and byssinosis was larger for smoking than for nonsmoking male cotton workers. CONCLUSIONS: Cessation of textile work was significantly associated with improvement in lung function and respiratory symptoms. The positive effect of work cessation was greater for cotton workers than for silk workers. For cotton workers, the improvement in lung function loss after cessation of textile work was greater among smokers, but no differences were observed for silk workers.

Prevalence of byssinosis in spinning and textile workers of Karachi, Pakistan.

The authors measured prevalence of byssinosis in spinning and textile workers of Karachi, Pakistan, and examined association of the disease with demographic and environmental factors. This was a cross-sectional study conducted in 3 spinning and textile mills and 3 colonies inhabited by spinning and textile workers. A precoded questionnaire was administered to the workers and followed by physical and clinical examination. Among 362 textile workers, the authors found the prevalence of byssinosis to be 35.6%. Educational status of the workers and section of the mill were significantly associated with prevalence of the disease. The authors conclude that there is a high prevalence of byssinosis in spinning and textile workers of Karachi. Furthermore, low education level and work in the spinning section of the mill appear to contribute significantly to the high prevalence of the disease in Pakistan.

Byssinosis: as seen in cotton spinning mill workers of Karachi.

OBJECTIVE: To identify Byssinosis in cotton spinning mill workers, probable associations of disease with factors such as different work areas, safety gadget usage and overtime and to ascertain proportions of byssinosis to accidental injuries. METHODS: This study was conducted in a spinning mill of Karachi in June 2006. Mill workers who had worked for a period of minimum 5 years were selected. A sample size of 83 conveniently selected workers participated in the research study. Data collection was done via questionnaire, and pulmonary function tests. RESULTS: The mean age of the sample was 30 +/- 6.9 years. Of all the workers 72% used safety gadgets (masks) while working and 50% availed overtime. Smokers amounted to 31% of the total subjects. Around 35% workers complained of having respiratory ailments of which 19% (16 workers) closely matched byssinotic symptoms. Pulmonary Function Tests (PFTs) confirmed 13 of 16 workers to be byssinotics, with the remaining being labeled as Probables. The overall proportion of Byssinotics in the mill was 19.28% (95% C.I. 11-27) and that of accidental injuries was 22.9%. The association of byssinosis with respect to work areas was significantly high in Ring area (O.R. = 2.04) followed by carding (O.R. = 1.3). The association of byssinosis was also high in workers who did not use safety gadgets, e.g. dust masks (O.R = 4.89) and in people who worked overtime (O.R. = 1.82). Associations with respect to duration of employment and smoking could not yield significant results. CONCLUSION: Results indicate a very high probability of association of disease to non-usage of safety gadgets and overtime working. Studies comprising of a greater sample size would show precisely the overall prevalence of the disease.

Cotton dust lung diseases.

PURPOSE OF REVIEW: Although, in the industrialized world, there is a significant decline in the prevalence of cotton dust lung diseases, studies show an increasing incidence in the developing world. With rapid industrialization of the developing world, cotton dust-induced lung diseases are poised to become a global health problem. Discovery of other vegetable dusts causing similar conditions and appreciation of a wider variety of clinical features also make this an opportune time to review this topic. RECENT FINDINGS: In addition to chronic exposure-related byssinosis and less common forms of acute byssinosis, recent reports describe the rare occurrence of cotton dust-induced pulmonary fibrosis. New data also relate long-term cotton dust exposure to symptoms and physiologic changes of chronic obstructive pulmonary disease. There have also been new developments relating the pathogenesis of cotton dust airway disease to endotoxin lipopolysaccharide found in cotton dust and bract extracts. SUMMARY: Establishment of an association between prolonged exposure to cotton and other vegetable dusts and symptoms of chronic obstructive pulmonary disease widens the clinical implication of cotton dust exposure. In addition, accumulating knowledge of endotoxins will bring about promising new developments reshaping industrial safety standards and measures to prevent cotton dust exposure.

Prevalence of byssinosis and other respiratory problems among textile mill workers in Asaba, Nigeria.

OBJECTIVES: This study was conducted to determine the distribution and severity of byssinosis and other respiratory problems in the different operation sections in a textile mill industry in Asaba. PATIENTS AND METHODS: This is a cross-sectional and analytic study in which workers directly exposed to cotton dust are compared with those not directly exposed to cotton dust at one point in time. RESULTS: A total of 735 workers were interviewed and 437 workers had respiratory examinations carried out on them. Byssinosis was diagnosed in 8 out of 405 workers (prevalence of 1.98%) who were not directly exposed to cotton dust, and 21 out of 330 workers (prevalence of 6.36%) who were directly exposed to cotton dust. The difference was found to be statistically significant (chi2 =9.25; df=1; 0.01

A 20-year follow-up study on chronic respiratory effects of exposure to cotton dust.

In order to evaluate chronic effects of long-term exposure to cotton dust on respiratory health, and the role of dust and endotoxin, longitudinal changes in lung function and respiratory symptoms were observed prospectively from 1981 to 2001 in 447 cotton textile workers, along with 472 silk textile controls. The results from five surveys conducted over the 20-yr period are reported, including standardised questionnaires, pre- and post-shift spirometric measurements, work-area inhalable dust sample collections and airborne Gram-bacterial endotoxin analysis. Cotton workers had more persistent respiratory symptoms and greater annual declines in forced expiratory volume in one second (FEV1) and forced vital capacity as compared with silk workers. After exposure cessation, in the final 5-yr period, the rate of FEV1 decline tended to slow in nonsmoking males, but not in nonsmoking females. Workers who reported byssinotic symptoms more persistently suffered greater declines in FEV1. Chronic loss in lung function was more strongly associated with exposure to endotoxin than to dust. In conclusion, the current study suggests that long-term exposure to cotton dust, in which airborne endotoxin appears to play an important role, results in substantial adverse chronic respiratory effects.

[Other obstructive diseases: byssinosis, chronic bronchitis and occupational COPD and eosinophilic bronchitis]. / Otras enfermedades obstructivas: bisinosis, bronquitis crónica y EPOC de origen laboral y bronquitis eosinofílica.

Besides occupational asthma and diseases derived from acute inhalation, other obstructive diseases also have an occupational origin. Although at present byssinosis is a rare disease in Spain, we describe its characteristics because of its historical interest amongst occupational respiratory diseases and because it is still relevant in developing countries. Chronic bronchitis can also be related to exposure at work to dust and smoke, and is often referred to as "industrial bronchitis". Historically, the relation of CPOD to occupation has been subject to controversy, but nowadays this relationship is accepted; we describe the present evidence supporting this relationship. Finally, we describe eosinophilic bronchitis without asthma, an entity that was described for the first time in 1989 and that can sometimes have an occupational origin, sharing aetiological agents with occupational asthma.