The study of byssinosis in China: a comprehensive report

Cross-sectional studies were conducted during 1981-1983 among 861 textile workers in 3 cotton mills and 822 controls in 2 silk factories. Questionnaire and lung function tests were taken and inhalable dust concentrations were measured. Prevalence of byssinosis was 5.6%. Average dust concentrations were highest in carding rooms, 1.47-1.99 mg/m3. The correlations (r) between prevalence of byssinosis and dust concentrations was 0.64 (p less than 0.05). The prevalence of chronic bronchitis was 14.4% in cotton workers and 5.1% in controls (p less than 0.05). Acute FEV1 percent decrement (greater than 5%) was higher among cotton workers (32.1%) compared to controls (14.5%) (p less than 0.001). In one cotton blanket factory, the prevalence of byssinosis and chronic bronchitis was higher among workers in the high-dust work areas. Long-term effect studies included pulmonary function test among 173 cotton workers and 373 controls, retired 1-10 years, using the flow volume curve (FVC); chest X-rays of 140 pairs of cotton workers and controls with working tenures over 20 years; and examination of lobectomy specimens of 8 textile workers matched with 16 controls. In male cotton workers, only smokers had a prominent decrement of lung function indices, except FVC. For non-smoking females, there was no difference between the two groups. Additive effects were seen between smoking and dust exposure. According to the International Labor Organization (ILO) Pneumoconiosis Classification, the prevalence of abnormality (profusion greater than 1/0) was 4.3% and 8.7% in non-smoking controls and cotton workers. The interstitial changes on X-ray due to smoking would be much heavier. Additive effects also existed between smoking and dust exposures. No significant changes attributable to dust exposure were seen on pathological section of lobectomy specimens.     

Prevalence of byssinosis and respiratory symptoms among spinners in Sudanese cotton mills

Byssinosis, other respiratory symptoms, and ventilatory capacity were investigated in 186 male spinners in two Sudanese textile mills located in Khartoum and Hassaheisa. The prevalence of byssinosis was 37% among Khartoum spinners where coarse cotton was processed, significantly higher (p less than 0.01) than the 1% found among Hassaheisa spinners, where fine cotton was used. The prevalence of chronic bronchitis was 29% in Khartoum and 2% in Hassaheisa spinners. A significant reduction in forced expiratory volumes (FEV1 after a shift) was observed in spinners of both factories. Our findings provide evidence that very low rates or absence of byssinosis, related respiratory symptoms, and significant functional abnormalities (FEV1) in the late stages of cotton yarn processing all depend on the quality of cotton used and low levels of cotton dust concentration.     

Respiratory effects of cotton dust exposure in the cotton garnetting industry

We measured exposures to total dust, vertically elutriated dust, and endotoxin and studied acute pulmonary responses among 128 workers in the cotton garnetting and mattress assembly industries. Previous studies in this segment of industry have not characterized endotoxin exposures or related them to pulmonary responses. The median 8-hour time-weighted average total dust was 0.72 mg/m3, the median vertically elutriated dust was 0.22 mg/m3, and the median endotoxin concentration was 5.2 ng/m3. Ten percent of the subjects reported chest tightness or dyspnea on Mondays. Thirteen percent of the subjects reported symptoms of chronic bronchitis. Although there was no relationship between changes in pulmonary function across the workshift and either total dust, vertically elutriated dust, or endotoxin exposure, 13% of the subjects had greater than 5% decrements in FEV1 over the workshift.     

Respiratory disease in a textile factory in Nicaragua

This is the first epidemiologic study conducted in a textile mill in Nicaragua using techniques and diagnostic criteria similar to those used in the United States and England. The prevalence of byssinosis and nonspecific respiratory symptoms were studied in 194 workers in a cotton mill in Managua. Limited environmental sampling, performed using a vertical elutriator in yarn preparation and weaving areas, indicated that exposures were similar to those reported in other parts of the developing world. A modified translated version of the Medical Research Council respiratory questionnaire was administered. Pulmonary function tests were performed before and after the Monday workshift to measure across-shift change in ventilatory function. The prevalence of byssinosis was 5.9% and all the cases occurred among exposed women. Nonspecific respiratory symptoms were also more prevalent among exposed workers. After adjusting for age, gender, smoking habit, and work tenure, the exposure odds ratios for usual cough and usual phlegm were 3.3 and 2.2, respectively. The association between exposure and across-shift decrement in FEV1 was not significant. Byssinotic workers, however, had greater decrements in FEV1% than those without byssinosis: 5.5% versus 1.8%. A consistent gender effect was observed in which both exposed and unexposed women were found to have greater across-shift decrements in FEV1 than men. The gender difference existed among long-term workers as well as workers who had been employed less than 2 years. Results are related to cotton dust exposure, as has been documented elsewhere. The poorer health status of the women in this study population deserves follow-up.     

棉纺车间空气中可吸尘,内毒素浓度与工人呼吸道反应

本文对338名棉工进行了呼吸道反应调查.并测定了车间空气中粉尘浓度及内毒素浓度.发现前纺车间可吸尘浓度在O.18～1.62m g/m~3,内毒素浓度在94.91～2682.18ng/m~3,棉尘有关症状(包括棉尘病症状和不典型症状)和慢性支气管炎患病率均比对照组高,且与车间粉尘和内毒素浓度呈正相关.与5年前比较,可吸尘或内毒素累积接触量高的男、女工人FEV_1下降均较累积接触量低者明显。     

Respiratory function and symptoms in workers exposed simultaneously to jute and hemp.

The environment and health of a working population exposed simultaneously to jute and hemp were studied. Classical symptoms of byssinosis were not present but 21 workers (7%) complained of atypical tightness of the chest. The prevalence of chronic bronchitis among the exposed workers was statistically significant in comparison with controls. Effects of dust concentrations, age and duration of exposure on the prevalence of chronic bronchitis were studied. A statistically significant reduction in FEV1.0 at the end of a work shift occurred in all the exposed workers. Bronchodilators given after the shift showed that acute reductions in forced expiratory volumes were nearly fully reversible in all exposed workers. Smokers and those with chronic bronchitis had greater reductions in FEV1.0 values at the end of the work shift.     

Respiratory problems among cotton textile mill workers in Ethiopia

This study was conducted to investigate the prevalence of respiratory problems, in particular byssinosis, and to explore factors associated with their occurrence among a group of 595 randomly selected workers representing 40.5% of those exposed to dusty operations in a typical Ethiopian cotton textile mill. A standard questionnaire on respiration was administered and pre and postshift forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were determined for each worker; workers found to have byssinosis and other respiratory diseases were compared with workers having no respiratory diseases in terms of the level and duration of exposure to cotton dust and other variables. Multiple area air samples from different sections were analysed for elutriated cotton dust concentrations (0.86-3.52 mg/m3). The prevalence of byssinosis was 43.2% among blowers and 37.5% in carders in comparison with four to 24% among workers in other sections. Prevalence of chronic bronchitis ranged from 17.6 to 47.7% and bronchial asthma from 8.5 to 20.5% across all sections. Significant across shift decrements in FEV1 and FVC were seen in those workers with respiratory tract diseases compared with those workers without such diseases. A significant dose response relation for pulmonary function and respiratory illnesses was also found by regression analysis. Preventive measures are proposed. Further research including a nationwide survey of textile mills is suggested. This is the first epidemiological study of the textile industry in Ethiopia.     

Respiratory problems among cotton textile mill workers in Ethiopia.

This study was conducted to investigate the prevalence of respiratory problems, in particular byssinosis, and to explore factors associated with their occurrence among a group of 595 randomly selected workers representing 40.5% of those exposed to dusty operations in a typical Ethiopian cotton textile mill. A standard questionnaire on respiration was administered and pre and postshift forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were determined for each worker; workers found to have byssinosis and other respiratory diseases were compared with workers having no respiratory diseases in terms of the level and duration of exposure to cotton dust and other variables. Multiple area air samples from different sections were analysed for elutriated cotton dust concentrations (0.86-3.52 mg/m3). The prevalence of byssinosis was 43.2% among blowers and 37.5% in carders in comparison with four to 24% among workers in other sections. Prevalence of chronic bronchitis ranged from 17.6 to 47.7% and bronchial asthma from 8.5 to 20.5% across all sections. Significant across shift decrements in FEV1 and FVC were seen in those workers with respiratory tract diseases compared with those workers without such diseases. A significant dose response relation for pulmonary function and respiratory illnesses was also found by regression analysis. Preventive measures are proposed. Further research including a nationwide survey of textile mills is suggested. This is the first epidemiological study of the textile industry in Ethiopia.     

Respiratory function in workers employed in the glassblowing industry

A group of 80 men employed in the glassblowing industry was studied in order to investigate the effect of this occupational exposure on respiratory function. Eighty nonexposed workers were included in the study as a control group. Glassblowers had a significantly higher prevalence of chronic bronchitis, nasal catarrh, chronic sinusitis, and nasal bleeding than control workers; length of employment in the industry did not affect the prevalence of symptoms. Many of the glassblowers complained of work shift related symptoms. Measurement of lung function among glassblowers showed there were significant increases in the forced vital capacity (FVC) and the maximum flow rates at 50% and 25% of FVC on maximum expiratory flow volume (MEFV) curves (FEF₅₀, FEF₂₅) across the work shift. Glassblowers had significantly larger preshift FVC and forced expiratory volume in 1-second (FEV₁) measurements when compared to controls. Additionally, residual volume (RV) and RV/TLC% for the glassblowers were significantly increased while the diffusing capacity (DLCO) was normal (when compared to predicted values). Our data indicate that employment in the glassblowing industry contributes to the development of chronic respiratory findings. © 1993 Wiley-Liss, Inc.     

Respiratory symptoms and lung function in jute processing workers: a primary investigation

This paper presents the results of an investigation of respiratory symptoms and lung function of 404 workers who had been exposed to jute dust in a jute mill. Measurement of total dust concentration and analysis of dust composition were also conducted. Most workers in the jute mill were exposed to jute dusts containing less than 5% silica, whereas a few workers were exposed to dusts containing approximately 10-15% silica. Male smokers and nonsmokers in the dust-exposed group had a higher prevalence of cough and chest tightness compared with those in the control group. Among dust-exposed workers, female nonsmokers had a significantly higher prevalence of cough, chronic bronchitis, chest tightness, and dyspnea than those in the control group. Lung function tests showed that dust-exposed workers had a greater incidence of abnormal lung function than did control workers, as measured by percentage of predicted forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), and FEV1.0/FVC. Dust exposure was the main cause of respiratory symptoms and abnormal values of FEV1.0, but both cigarette smoking and dust exposure contributed to the abnormal values reported for FEV1.0.     

Byssinosis in Guangzhou, China.

OBJECTIVES--To study the prevalence of byssinosis and other respiratory abnormalities in workers exposed to cotton dust in Guangzhou in two factories that processed purely cotton. METHODS--All the 1320 workers exposed were included. The controls were 1306 workers with no history of occupational dust exposure. Total dust and inhalable dust were measured by Chinese total dust sampler and American vertical elutriator respectively. A World Health Organisation questionnaire was used. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured by a Vitalograph spirometer. RESULTS--The median inhalable dust concentrations ranged from 0.41 to 1.51 mg/m3 and median total dust concentrations from 3.04 to 12.32 mg/m3. The prevalence of respiratory abnormalities in the cotton workers were (a) typical Monday symptoms 9.0%; (b) FEV1 fall by > or = 5% after a shift 16.8%; (c) FEV1 fall by > or = 10% after a shift 4.2%; (d) FEV1 < 80% predicted 6.1%; (e) FEV1/FVC < 75% 4.0%; (f) cough or phlegm 18.2%; (g) chronic bronchitis 10.9%; and (h) byssinosis, defined by (a) plus (b) 1.7%. With the exception of (d), most of the prevalences increased with increasing age, duration of exposure, and cumulative inhalable dust exposure. No increasing trends of respiratory abnormalities were found for current total dust, inhalable dust, and cumulative total dust concentrations. Compared with controls, after adjustment for sex and smoking, with the exception of (d), all the pooled relative risks of respiratory abnormalities were raised for cotton exposure. CONCLUSION--It is concluded that cumulative inhalable cotton is likely to be the cause of byssinotic symptoms, acute lung function decrements, cough, or phlegm, and chronic bronchitis.     

Is chronic airway obstruction from cotton dust exposure reversible?

BACKGROUND: Exposure to cotton dust is known to cause chronic airway obstruction, but there is little information on whether the obstructive impairment is reversible after the exposure stops. METHODS: Longitudinal changes in lung function were evaluated among 429 cotton textile workers and 449 silk workers in Shanghai, China, beginning in 1981. Both active and retired workers were tested every 4 to 6 years for 15 years. RESULTS: Overall, cotton workers had greater annual declines in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Compared with active workers, retired cotton workers had lower annual loss of FEV1, although the retired workers had a greater loss during their active employment than the currently active workers. No such trends were detected in silk workers. Annual declines in FEV1 in retired cotton workers were smaller with increasing time since retirement. Multivariate analysis showed that retirement was a substantial contributing factor for improved FEV1 and FVC in the cotton workers, especially among those who did not smoke. Correspondingly, remission of airflow obstruction, defined as a ratio of FEV1 and FVC of less than 70%, was more common in retirees than in the active workers, and more common in nonsmokers than in smokers. CONCLUSION: Chronic airway obstruction related to long-term exposure to cotton dust may be partially reversible after the exposure ceases, although lung function does not return to the level found in unexposed workers.     

Ventilatory function and allergic skin tests in cotton mill workers

Ventilatory capacity, chronic respiratory symptoms and respiratory diseases as well as intradermal skin tests were registered in a group of 112 cotton workers. The prevalence of chronic respiratory symptoms and respiratory diseases was higher among the exposed than among control workers although the differences were statistically significant only for chronic cough, nasal catarrh and byssinosis in women and for chronic cough, chronic phlegm and byssinosis in men. A similar prevalence of byssinosis was noted in women (29.4%) and in men (29.5%). Among textile workers mostly byssinosis grade 1/2 was found (women 22.1%, men 20.5%). There were statistically significant acute reductions over work shift for forced vital capacity (FVC) and one-second forced expiratory volume (FEV1). In men the values were somewhat lower than the expected normal values. A very small number of workers demonstrated positive intradermal skin tests to cotton allergen (exposed 8.2%, control 1.8%). Our data indicate that exposure to cotton dust may lead to the development of respiratory symptoms and diseases as well as to acute changes in ventilatory capacity but without an allergic reaction.     

Respiratory disease in cotton textile workers in the People's Republic of China. II. Pulmonary function results

Pulmonary function tests were performed pre and post workshift on 887 textile workers with at least two years of employment in two cotton mills and one silk mill in Shanghai, the People's Republic of China. Environmental sampling was performed with vertical elutriators, and pulmonary function was performed with standardized techniques. Cotton textile workers were found to have greater across-shift decrements in forced expiratory volume in 1 s (FEV1.0) than silk workers. Increasing duration of exposure resulted in increasing acute decrements in FEV1.0, although significant acute decrements were found in workers with less than five years of exposure. The acute changes in FEV 1.0 were noted in both symptomatic and asymptomatic cotton workers, though the difference between the across-shift change in FEV1.0 (delta FEV1.0%) of the byssinotics and nonbyssinotics increased as work duration increased. There was no difference in preshift FEV1.0 between the cotton and silk workers, but several selection factors likely influenced the observations.     

Respiratory disease in cotton textile workers in the People's Republic of China. I. Respiratory symptoms

The prevalence of byssinosis and nonspecific respiratory symptoms was studied in 887 textile workers with at least two years of employment in two cotton mills and one silk mill in Shanghai, the People's Republic of China. A standardized respiratory questionnaire was used, and environmental sampling was performed with vertical elutriators and colorimeter grading. Eight percent of the cotton textile workers complained of byssinosis. The reports of byssinosis were mostly mild (grade 1/2), more prevalent among women, and unrelated to duration of employment or elutriator dust levels. Nonspecific respiratory symptoms were significantly more prevalent among cotton textile workers than silk workers. After adjustment for age, gender, and smoking in logistic regression models, the odds ratios for the effect of working in cotton textile mills on chronic bronchitis, chronic cough, and frequent chest illness were 3.3, 2.9 and 4.7, respectively. Although none of the symptoms were related to current dust levels, the range of exposures was narrow, and information was only available on current levels of cotton dust. This study represents the first respiratory survey of the textile industry in China using diagnostic criteria similar to that used in the United States and England; it defines a cohort for prospective investigation.     

Lung function in Lancashire cotton and man made fibre spinning mill operatives.

OBJECTIVES--This survey was conducted to investigate current lung function levels in operatives working with cotton and man made fibres. Dust concentrations, smoking history, and occupational details were recorded so that factors influencing lung function could be identified. METHODS--A cross sectional study of respiratory symptoms and lung function was made in 1057 textile spinning operatives of white caucasian extraction. This represented 96.9% of the total available working population to be studied. Most (713) worked currently with cotton. The remainder worked with man made fibre. Lung function was assessed by measuring forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Exposure to cotton dust was measured in the work area and personal breathing zones, and retrospective exposure to cotton dust over a working life was estimated with accurate work history and best available hygiene data. RESULTS--3.5% of all operatives had byssinosis, 55 (5.3%) chronic bronchitis, 36 (3.5%) work related persistent cough, 55 (5.3%) non-byssinotic work related chest tightness, and 56 (5.3%) work related wheeze. A total of 212 static work area dust samples (range 0.04-3.23 mg/m3) and 213 personal breathing zone samples (range 0.14-24.95 mg/m3) were collected. Percentage of predicted FEV1 was reduced in current smokers (mean 89.5, 95% confidence interval (95% CI) 88-91) in comparison with non-smokers (93.1, 90.5-94.1) and FVC was reduced in operatives currently working with man made fibre (95.3, 93.8-96.9) in comparison with cotton (97.8, 96.6-99.0). Regression analysis identified smoking (P < 0.01), increasing age (P < 0.01), increasing time worked in the waste room (P < 0.01), and male sex (P < 0.05) as being associated with a lower FEV1 and FVC. Current and retrospective cotton dust exposures did not appear as predictor variables in the regression analysis although in a univariate analysis, FEV1 was reduced in those operatives exposed to high dust concentrations assessed by personal and work area sampling. DISCUSSION--This study has documented loss of lung function in association with exposure to cotton dust. Those operatives with work related symptoms had significantly lower FEV1 and FVC than asymptomatic workers. Although lung function seemed to be affected by high dust exposures when operatives were stratified into high and low exposure groups, regression analysis did not identify current dust concentrations as an independent factor influencing loss. Smoking habit was found to explain most of the measured change in FEV1 and FVC. It is likely that smoking and dust exposure interact to cause loss of lung function in cotton textile workers.     

Respiratory findings in spice factory workers

The respiratory consequences of working in the spice industry were studied in 92 female spice factory workers (mean age, 36 yr; mean exposure, 12 yr). A control group of 104 female workers employed in a nondusty industry was also studied. The prevalence of chronic respiratory symptoms was significantly higher in the exposed than in the control group. In particular, the prevalence of dyspnea (57.6%), chronic cough (22.8%), chronic phlegm and chronic bronchitis (19.6%), nasal catarrh (37.0%), and sinusitis (22.2%) was high when compared to controls (p less than .01). Among spice factory workers, a high prevalence of acute symptoms during the workshift was recorded. Acute reductions in lung function were statistically significant over the workshift for forced vital capacity (FVC), -2.0%; forced expiratory volume in one second (FEV1.0), -3.0%; and for maximum expiratory flow rates at 50% (FEF50), -8.3% and at 25% (FEF25), -15.2% measured on maximum expiratory flow-volume (MEFV) curves. No difference was found in across-shift ventilatory function in workers with or without chronic respiratory symptoms, except for FEF25 (with symptoms, 16.7%; without symptoms, 9.6%). Preshift administration of 40 mg of disodium cromoglycate (DSC) inhaled 15 min before the workshift significantly diminished acute reductions in FEF50 and FEF25 in exposed workers. Monday preshift FEF50 and FEF25 in exposed workers were significantly lower than in control workers (p less than .01), which suggests an early irreversible component to this illness.     

Respiratory function in animal food processing workers

A group of 71 men employed in animal food processing was studied to assess the prevalence of acute and chronic respiratory symptoms and the presence of lung function abnormalities. In addition, a control group of 55 unexposed men was studied for the prevalence of chronic respiratory symptoms. A significantly higher prevalence for most of the chronic respiratory symptoms was found among the exposed workers compared to the control workers. Those workers who smoked had a significantly higher prevalence of chronic cough, chronic phlegm, chronic bronchitis, and chest tightness than the smokers in the control group. For nonsmokers, the differences between exposed and control workers were significant for chronic phlegm and chest tightness. The frequency of acute symptoms associated with the work shift was high among the animal food workers. There were significantly lower measured values for FVC, FEV1, and FEF50 in the exposed group (smokers and nonsmokers) compared to predicted lung function values. In smokers, all measured parameters of ventilatory capacity were significantly less than predicted; for nonsmokers, the FVC and FEV1 were less than normal. Our data indicate that exposure to dust in the animal food industry may be associated with the development of acute and chronic respiratory symptoms and the impairment of lung function. Smoking, in this setting, appears to aggravate these changes.     

Respiratory and allergic disorders in workers exposed to grain and flour dusts

Symptoms suggestive of chronic bronchitis or chronic productive cough were found in 29.0% of 100 workers exposed to flour dust in a flour mill, 26.0% presenting with chronic cough and 29.0% with phlegm. In the control group, the prevalence of chronic cough and phlegm was only 6.6% in each category. While 22.0% of the workers complained of chest tightness on exposure, and 18.0% developed symptoms and signs of bronchial asthma, only 3.3% of the controls complained of chest tightness and 3.3% of asthma. Respiratory measurements before and after the working shift showed a significant drop (p less than .001) in the forced expiratory volume in 1 sec (FEV1.0) and forced vital capacity (FVC) in the exposed group. Fifty-eight percent of the exposed workers experienced a drop in FEV1.0 and FVC measurements. A positive skin reaction to wheat flour extract was recorded among 31% of the exposed workers vs. 10% of the controls. The prevalence of other associated allergic symptoms was 17.0% and 19.0% for sinusitis and conjunctivitis, respectively; in the unexposed group, the prevalence of the same symptoms ranged between 3.3% and 6.6%. A strong association was revealed between exposure to grain and flour dusts and the prevalence of respiratory and allergic disorders.     

Chronic bronchitis, work related respiratory symptoms, and pulmonary function in welders in New Zealand

OBJECTIVES: A cross sectional study of respiratory symptoms and lung function in welders was performed at eight New Zealand welding sites: 62 current welders and 75 non-welders participated. METHODS: A questionnaire was administered to record demographic data, smoking habit, and current respiratory symptoms. Current and previous welding exposures were recorded to calculate a total lifetime welding fume exposure index. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) were measured before the start of the shift. RESULTS: There were no significant differences in ethnicity, smoking habits, or years of work experience between welders and non-welders. Symptoms of chronic bronchitis were more common in current welders (11.3%) than in non-welders (5.0%). Of those workers with a cumulative exposure index to welding fume > or = 10 years, 16.7% reported symptoms of chronic bronchitis compared with 4.7% of those with a cumulative exposure index < 4 years (odds ratio (OR) 4.1, 95% confidence interval (95% CI) 0.90 to 17.6). Workers with chronic bronchitis had significantly lower measures of baseline PEF (p = 0.008) and FEV/FVC ratio (p = 0.001) than workers without chronic bronchitis. Multivariate analysis showed that current smoking (OR 9.3, 1.0 to 86.9) and total exposure index to welding fumes > 10 years (OR 9.5, 1.3 to 71.9) were independent risk factors for chronic bronchitis. The report of any work related respiratory symptom was more prevalent in welders (30.7%) than non-welders (15.0%) and workers with these symptoms had significantly lower FEV, (p = 0.004) and FVC (p = 0.04) values. Multivariate analysis identified a high proportion of time spent welding in confined spaces as the main risk factor for reporting these symptoms (OR 2.8, 1.0 to 8.3). CONCLUSION: This study has documented a high prevalence of symptoms of chronic bronchitis and other work related respiratory symptoms in current welders. Also, workers with chronic bronchitis had reduced PEF and FEV/FVC compared with those without chronic bronchitis. These symptoms related both to cigarette smoking and a measure of lifetime exposure to welding fume.