Prevalence of byssinosis in Swedish cotton mills.

The prevalence of byssinosis and of chronic bronchitis was studied in a questionnaire investigation among workers in bale opening areas, carding rooms, and spinning rooms in five Swedish cotton mills. Airborne dust and Gram-negative bacteria was measured. Nineteen per cent of the interviewed workers reported symptoms of light byssinosis (grade 1/2). The prevalence of symptoms was not related to the duration of employment, and cases of byssinosis were found among people who had worked in cotton mills for only a few years. A significantly higher proportion of male than female workers reported symptoms. No difference in the extent of byssinosis was found between smokers and non-smokers, but the prevalence was significantly higher among those workers who had ceased smoking. The prevalence of byssinosis was related to the number of airborne viable Gram-negative bacteria as well as to the dust level in the different mills.     

Endemic Byssinosis in an Egyptian Village

Previous epidemiological surveys of flax byssinosis may have underestimated the incidence of permanent pulmonary disability by failing to reach those who have had to leave work. In the present study a representative sample of the inhabitants of a village where flax is processed both in the homes and in small plants was examined for byssinosis. The one in five random sample included a total of 190 male family heads living in the village. Dust exposure was evaluated. The study showed that 48·4% of the sample had byssinosis, and this included 92·5% of those working with flax in their homes and 75% of those working in plants. Permanent disability from byssinosis was present in 2·6% of the total sample and 12·1% of those exposed to dust for more than 20 years, whereas 75·8% of the latter group had symptoms of the earlier grades of byssinosis. It is concluded that prolonged exposure to flax dust did not result in a high incidence of permanent disability, and that is disability is not necessarily an eventual outcome in flax byssinosis. The absence of air pollution in the village may play a role in lowering the probability of workers becoming disabled by byssinosis in spite of the high prevalence of symptoms.     

Byssinosis Prevalence and Flax Processing

Previous evidence suggested that byssinosis in flax workers is caused by the inhalation of dust of biologically retted flax. In the present study no cases of byssinosis were found among workers in a flax plant which produces yarn by chemical degumming instead of biological retting. The absence of byssinosis in this plant could not be attributed to differences in the quantities of dust developed as compared with the conventional retting procedure.

These findings support the view that the agent in flax dust which causes symptoms of byssinosis originates during biological retting of flax and is absent from unretted flax. Chemical degumming of flax appears to be superior to biological retting procedures with respect to the health of the workers.

     

Byssinosis in Hong Kong

After a report in 1980 of the first three diagnosed locally cases and a preliminary epidemiological investigation that found little evidence of the disease, a survey was aimed at determining the prevalence of byssinosis in Hong Kong. Some 1776 workers in six cotton mills were studied using the standard MRC questionnaire and portable spirometers. Only 48 (2.7%) of the mill workers had symptoms acceptable for a diagnosis of byssinosis. The pattern of relation to dust exposure levels was similar to findings in other countries: blowing and carding process operatives had twice the prevalence rate of the spinners. Another 178 workers (10%) had symptoms of chest tightness or breathlessness or both that were not related to the first exposure after a break and therefore did not fit the standard diagnosis. Some 257 workers (14.5%) had chronic obstructive airflow disease but only 12 (4.7%) had chronic bronchitis. Job mobility had self selection of sensitive cases out of cotton dust exposure seem the most likely explanations for the low prevalence. The significance of non-specific lung ailments needs further assessment to elucidate the possible connection with cotton dust exposure.     

Byssinosis in Hong Kong.

After a report in 1980 of the first three diagnosed locally cases and a preliminary epidemiological investigation that found little evidence of the disease, a survey was aimed at determining the prevalence of byssinosis in Hong Kong. Some 1776 workers in six cotton mills were studied using the standard MRC questionnaire and portable spirometers. Only 48 (2.7%) of the mill workers had symptoms acceptable for a diagnosis of byssinosis. The pattern of relation to dust exposure levels was similar to findings in other countries: blowing and carding process operatives had twice the prevalence rate of the spinners. Another 178 workers (10%) had symptoms of chest tightness or breathlessness or both that were not related to the first exposure after a break and therefore did not fit the standard diagnosis. Some 257 workers (14.5%) had chronic obstructive airflow disease but only 12 (4.7%) had chronic bronchitis. Job mobility had self selection of sensitive cases out of cotton dust exposure seem the most likely explanations for the low prevalence. The significance of non-specific lung ailments needs further assessment to elucidate the possible connection with cotton dust exposure.     

Annual decline of ventilatory capacity and change in acute respiratory response in hemp exposure over a 10-year period

Summary A follow-up study of the effect of exposure to hemp dust on respiratory function over a 10-year period (1963–1973) was conducted in 24 female non-smoking hemp workers. The prevalence of byssinosis in 1973 (70.8%) was found to be significantly higher than 10 years earlier in 1963 (33%) (P<0.01). The prevalence of all other chronic respiratory symptoms was also considerably increased. In the control group the prevalence of all chronic respiratory symptoms was practically the same during both surveys.In hemp workers, there was a significant acute fall over the work shift in FEV_1.0 (1-second forced expiratory volume) and FVC (forced vital capacity), both in 1963 and 1973 (P<0.01), except in the group of workers who did not have byssinosis either in 1963 or in 1973. The lowest mean annual decline of FEV_1.0 within the 10-year period was found in the group without byssinosis in both 1963 and in 1973 (27 ml), followed by the group without byssinosis in 1963 but with byssinosis in 1973 (38 ml). The largest annual decline was observed in the subjects with byssinosis during both surveys (55 ml). The mean annual FEV_1.0 decline in the control group was 22 ml.     

RESPIRATORY SYMPTOMS IN MEN WHO HAD PREVIOUSLY WORKED IN A FLAX MILL IN NORTHERN IRELAND

An attempt was made to assess the importance of selective discharge by death or retirement of workers with respiratory symptoms in a flax mill in Northern Ireland.

One hundred and two men who had worked in a flax mill during 1952-62 and who were aged 35 years or more at the time of leaving were followed up. Fourteen of the men had died and 75 were interviewed. The proportion who had dyspnoea on exertion at the time of interview was significantly higher (at P<0·05) in those who had had byssinosis than in those who had not had byssinosis while in the mill, although the proportions with dyspnoea in preparers and nonpreparers did not differ significantly. The proportion who stated that they had left the mill because of exertional dyspnoea of increasing severity was also significantly higher among those who had had byssinosis than among those who had not. Most of the men who had had byssinosis stated that their symptoms had improved after they left the mill, though some thought that work in the mill had permanently affected their chests, and two said that their symptoms had become gradually more severe since discharge. Of the 14 who had died, certificates of the cause of death were traced for 12, in none of which had respiratory disease been entered as a cause of death. In one man who had been a flax preparer, chronic bronchitis had been considered a `significant condition, contributing to the death'.

The study indicates that any estimate of the prevalence of byssinosis based solely on the examination of workers in the mills underestimates the true magnitude of the problem.

     

Additive effect of smoking and cotton dust exposure on respiratory symptoms and pulmonary function of cotton textile workers

One hundred and sixty-nine and 175 cotton textile workers (CTWs) were enrolled in the first (1991) and second (1996) surveys to investigate the prevalence of byssinosis. The synergistic effect of smoking on cotton dust exposure was also evaluated. Although the difference in prevalence of abnormal pulmonary function between the first (38.5%) and second study (38.9%) was not statistically significant, smokers had significantly higher frequency than nonsmokers in both surveys. A significant trend existed between the cotton dust levels and the frequency of abnormal lung function. The significant trend was also noted in both smokers and nonsmokers. The frequency of respiratory symptoms and the prevalence of severe byssinosis in the second survey (14.9% and 12.6%, respectively) were significantly lower than that in the first survey (39.7% and 21.9%, respectively). The reduction of symptoms was due to remodeling of this old cotton mill. The prevalences of respiratory symptoms and byssinosis in smokers being significantly higher than in nonsmokers only found in the first survey, but not found in the second survey. These results indicate that smoking potentiates the effect of cotton dust exposure on respiratory symptoms and byssinosis. The second study reveals high prevalence of byssinosis still existed in Taiwanese cotton mill, although the prevalence was declining. Smoking was found to show an additive effect on cotton dust exposure. Anti-smoking campaign, occupational health program to reduce the dust exposure, and periodical medical examination are measures to prevent from byssinosis.     

BYSSINOSIS AND OTHER RESPIRATORY SYMPTOMS IN FLAX WORKERS IN NORTHERN IRELAND

A study of byssinosis and other respiratory symptoms in 2,528 flax workers aged 35 years and over in Northern Ireland is reported. This represented 82·5% of the total available population. Only 3% of workers were not seen because of absence or a refusal to co-operate. Workers were interviewed using a questionnaire based on the Questionnaire on Respiratory Symptoms (Medical Research Council, 1960a) with additional questions relating to respiratory symptoms at work.

Byssinosis was found in workers in all stages of the industry, though its prevalence was highest in flax preparers; wet spinners and wet polishers did not appear to be at serious risk of developing the condition. When the effects of other relevant factors had been allowed for, e.g., age, duration of employment, and smoking habits, differences between the prevalence in the two sexes were found to be very small. The associations between byssinosis and the age of workers and their durations of employment in flax-preparing occupations were complex, and it was thought that a selective discharge of affected workers before the study might, in part at least, explain the absence of marked associations between these variables.

Marked associations were found between both chronic bronchitis and exertional dyspnoea and the type of occupation in the mill. Workers in the early preparing occupations had a considerably higher prevalence of these conditions than expected on a null hypothesis. There were also marked associations between byssinosis and bronchitis, and between byssinosis and dyspnoea. The possible importance of these associations with regard to the aetiology of byssinosis is discussed, and it is suggested that byssinosis represents an acute, specific effect of certain textile dusts on the respiratory system, superimposed on a non-specific chronic bronchitic process.

     

Byssinosis and serum IgE concentrations in textile workers in an Italian cotton mill

ABSTRACT The relationship between serum concentrations of total IgE and byssinosis and other respiratory symptoms was evaluated in 352 textile workers (90 men, 262 women) at a cotton mill in Friuli-Venezia Giulia, Italy. The subjects were aged from 20 to 61 (mean 44) and the mean duration of employment was 20 years. One hundred and eight subjects (30·7%) were smokers. Only 2% had a positive history of atopy. A standardised questionnaire showed chronic bronchitis in 96 textile workers (27·3%) and byssinosis in 63 (17·9%). The prevalence of respiratory disorders was the same for men and women but was higher in the carding room than in other work areas. Total serum IgE concentrations (RIST, Phadebas) were analysed after log transformation. The geometric mean was 192·7 IU/ml, with no significant difference between the two sexes. This mean concentration of IgE is much higher than that reported internationally for non-atopic subjects, but similar to values found in the Italian population. The IgE concentrations of the workers in the main departments (carding, spinning, and weaving) showed no significant difference. The geometric means were not different in subsamples stratified according to respiratory diseases (cases of pure and cases of mixed forms of chronic bronchitis and byssinosis). A negative result was obtained when IgE concentrations of 289 subjects without byssinosis (¯x = 188·4 IU/ml) and 63 with byssinosis (¯x = 212·6 IU/ml) were compared; there was also no trend when the results were analysed by clinical grade of byssinosis. The same negative pattern occured when the serum IgE concentrations were examined in patients with byssinosis with different grades of chronic change in FEV₁. The results of this study support the hypothesis that there is no relationship between total serum IgE concentrations and byssinosis.     

Strategies for prevention of byssinosis

Cotton dust is a heterogeneous mixture of plant parts and contaminants from the soil, weeds, and microorganisms. Research to control byssinosis has focused on methods to reduce the trash associated with harvested fiber and control the dust in the textile mill environment. Dust control has been effective in reducing the prevalence of byssinosis, but because cotton dust is a heterogeneous mixture of components, simple reduction in dust levels does not always assure the prevention of byssinosis. Research to identify the agents that cause byssinosis and development of methods to eliminate those agents from cotton is needed to prevent new cases of byssinosis.     

Effects of Hemp Dust Exposure on Nonsmoking Female Textile Workers

Symptoms of byssinosis were found in 39% of 102 female hemp workers who were nonsmokers. A higher prevalence of chronic bronchitis (P < 0.01) was found in workers with symptoms of byssinosis than in those without such symptoms. In hemp workers, either with or without symptoms of byssinosis, FEV_1.0 and FVC significantly decreased during work on the study days, Mondays and Thursdays; significantly lower reductions were registered on Thursdays. Inhalation of metaproterenol sulfate (Alupent) before work significantly diminished FEV_1.0 reduction, although not completely preventing it. Metaproterenol inhalation after work significantly increased FEV_1.0, indicating the reversibility of acute lung function changes during work. Comparison of lung function values measured before work with values obtained in the control group indicates a chronic effect of hemp dust on ventilatory function.     

Ocular and nasal irritation in operatives in Lancashire cotton and synthetic fibre mills.

OBJECTIVES--To document the prevalence of work related ocular (eyeWRI) and nasal (noseWRI) irritation in workers in spinning mills of cotton and synthetic textile fibres and to relate the prevalence of symptoms to atopy, byssinotic symptoms, work history, and measured dust concentrations in the personal breathing zone and work area. METHODS--A cross sectional study of 1048 cotton workers and 404 synthetic fibre workers was performed. A respiratory questionnaire was given to 1452 workers (95% of the total available population). Atopy was judged by skin prick tests to three common allergens. Work area cotton dust sampling (WAdust) was carried out according to EH25 guidelines in nine of the 11 spinning mills included in the study. Personal breathing zone dust concentrations were assessed with the IOM sampler to derive total dust exposure (PTdust) and a concentration calculated after the removal of fly (Pless). RESULTS--3.7% of all operatives complained of symptoms of byssinosis, 253 (17.5%) complained of eyeWRI and 165 (11%) of noseWRI. These symptoms did not relate to atopy or byssinosis, or correlate univariately with any measure of cotton dust exposure (noseWRI v WAdust r = 0.153, PTdust r = 0.118, eyeWRI v WAdust r = 0.029, PTdust r = 0.052). Both of these symptoms on logistic regression analysis were related to being of white origin (P < 0.001), female sex (P < 0.001), and younger age (P < 0.001). With regression analysis, there was a negative relation between dust concentration and prevalence of symptoms. CONCLUSION--Work related ocular and nasal irritation are the most common symptoms complained of by cotton textile workers. There was no relation between these symptoms and atopy, byssinosis, or dust concentration. It is likely that they relate to as yet unidentified agents unrelated to concentration of cotton dust.     

Prevalence of Byssinosis and Dust Levels in Flax Preparers in Northern Ireland

The association between the prevalence of both byssinosis and chronic bronchitis and the level of airborne dust was examined in workers in preparing departments in flax mills in Northern Ireland. A weak association between the dust level and byssinosis was found but not between the dust level and chronic bronchitis. It is suggested that the disparity of these associations may have arisen because the diagnosis of byssinosis, as in most recent published studies, was based on relatively acute and reversible symptoms which are more likely to be closely related to the current dust levels than the slowly developing symptoms on which the diagnosis of chronic bronchitis was based. Furthermore an association between chronic bronchitis and the dust levels is likely to be obscured to some extent by the effects of other non-industrial respiratory irritants such as tobacco smoke. Some hypotheses of the basic aetiology of byssinosis are discussed.     

Respiratory symptoms and ventilatory function in sisal dust exposure

Summary A study of respiratory symptoms and ventilatory function was made in a group of 51 non-smoking female workers exposed to sisal dust and 51 control subjects matched in age and height. A higher prevalence of persistent cough (17.6%), persistent phlegm (13.7%), chronic bronchitis (9.8%) and nasal catarrh (19.6%) was found in sisal workers than in controls (5.9, 5.9, 5.9 and 0%, respectively). Not a single case of byssinosis was found in the workers surveyed.In sisal workers, FEV_1.0, FVC and PEF significantly decreased over the work shift (P<0.01). Control workers did not show significant acute changes in ventilatory function over the shift. Inhalation of Alupent (orciprenaline) before the shift significantly diminished acute reductions in ventilatory capacity during the shift. The results suggest that sisal dust does not cause byssinosis but affects ventilatory function of the exposed workers.     

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.     

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.     

Effects of Histamine Aerosol in Byssinotic Subjects

The changes in symptoms and lung function tests of 26 cotton cardroom workers were investigated before and after inhalation of histamine aerosols. Three subjects with no chest symptoms and 11 with uncomplicated byssinosis showed no evidence of any pulmonary reaction, but 12 bronchitic byssinotic subjects showed evidence of the pulmonary hypersensitivity found in patients with chronic bronchitis alone.

These findings cast doubt on the possible role of non-antigenic histamine liberators in the mechanism of production of `return-to-work' tightness in byssinosis.

     

Relationships between dust level and byssinosis and bronchitis in Lancashire cotton mills

Berry, G., Molyneux, M. K. B., and Tombleson, J. B. L. (1974). British Journal of Industrial Medicine,31, 18-27. Relationships between dust level and byssinosis and bronchitis in Lancashire cotton mills. A prospective survey of workers in 14 cotton and two man-made fibre spinning mills was carried out. A questionnaire on respiratory symptoms was completed at the start of the survey by 1 359 cotton workers and 227 workers in man-made fibre mills and again two years later by about half of these workers. Dust measurements were available for 772 women and 234 men cotton workers.

The prevalence of bronchitis was found to be unrelated to dust level but for women was related to years of exposure. The change in symptoms of bronchitis was unrelated to dust level or to length of exposure. There was, however, an increased prevalence of bronchitis in the cotton mills when compared with the man-made fibre mills, and also over the two-year period a greater proportion of symptom-free workers developed symptoms and a lower proportion of those with symptoms lost their symptoms in the cotton mills than in the man-made fibre mills.

The prevalence of byssinosis was related to smoking habits, the smokers having about 1·4 times as much byssinosis as the non- and ex-smokers after allowing for exposure. Byssinosis was associated with the dust level and years of exposure, more so for the women, and an association between the incidence of new cases over the two years and dust level was also found. After allowing for dust level, years of exposure, and smoking there were still differences between the occupational groups in byssinosis prevalence. Strippers and grinders had the highest prevalence followed by drawframe tenters. Speedframe tenters, card tenters, and comber tenters had similar prevalences and ring spinners the lowest.

     

Dust Diseases in Dundee Textile Workers: An Investigation into Chronic Respiratory Disease in Jute and Flax Industries

A survey of respiratory symptoms and function was carried out in Dundee among 123 men and women in the jute industry and 242 in the flax industry. The selection of workers was biassed in favour of those working in the dustier departments as judged by eye and those in the older age groups. A group of 72 men in a heavy engineering firm were also selected as controls for comparison.

Chronic bronchitis, as defined by Ogilvie and Newell (1957) was recorded in 27% of those interviewed, whose average age was 49. Byssinosis of various grades was recorded in 30% of all working in flax; of these 35 had cough alone worse on Monday, 34 had other respiratory symptoms worse on Monday and in only four persons did the exacerbation persist longer in the week.

In spite of the occurrence of byssinosis, chronic bronchitis was no more prevalent among flax workers than among the others, the average ventilatory function was no worse, and radiographs of the chest revealed no differences. The characteristic fall in expiratory flow rate during the course of exposure to flax dust on Mondays is similar to that found in cotton workers, and is absent in jute workers and in flax workers not admitting to symptoms of byssinosis.