A population study in cotton ginnery workers in the Sudan

Khogali, M. (1969).Brit. J. industr. Med.,26, 308-313. A population study in cotton ginnery workers in the Sudan. An epidemiological study in cotton ginneries in the Sudan covered 323 permanently employed ginnery workers, a random sample of 35 seasonal farfara workers, and a control group of 24 members of a fire brigade. All the workers studied were men.

The study showed a prevalence of byssinosis (defined as chest tightness starting on return from the annual holiday and continuing for at least three consecutive days) in 20% of the ginnery workers and in 48·6% of the farfara workers. Workers exposed to dust showed a mean fall in F.E.V._1·0 of -0·10 litre during the shift, while workers not so exposed showed a mean rise of +0·23 litre; this difference was statistically significant. The F.E.V._1·0 was adjusted for age and standing height. The adjusted means of F.E.V._1·0 were significantly lower for workers exposed to dust compared with those in the control group.

The workers with byssinosis showed a statistically significant fall in F.E.V._1·0 when compared with all ginnery workers; and a highly significant fall when compared with cotton workers without chest symptoms. An attempt was made to grade the byssinotics according to the extent of fall in F.E.V._1·0 during the shift.

The concentration of fine dust (< 7 μ) was measured in each work place. There was a statistically significant association between the prevalence of byssinosis and the concentration of fine dust when comparing the ginnery and farfara workers. Also, there was a significant relationship between the mean adjusted F.E.V._1·0, the mean fall in F.E.V._1·0, and the fine dust concentration.

     

Byssinosis: a follow-up study of cotton ginnery workers in the Sudan.

A follow-up study of lung function tests and dust measurements was undertaken in ginnery workers employed in five ginning factories. Respiratory symptoms and respiratory function tests (FEV1 and FVC) were first recorded in 1967 on a total of 382 workers (323 permanently employed ginnery workers, 35 seasonal farfara workers, and 24 fire brigade men as controls). In 1969 after a six-month break from ginning before the start of the season, a follow-up study of lung function tests was undertaken on 96% of the same workers (306 ginnery workers, 35 farfara, and 24 fire brigade men). Because of the lapse of two years a new adjustment for age and height was made so as to compare the FEV1 measured in the follow-up study. The fire brigade men showed an expected fall in FEV1 during the two-year period, whereas the ginnery workers showed a rise presumably because they had had no dust exposure during the previous six months. The differences between the degree of change in these groups were statistically significant. In 1967 only the fine dust (less than 7 mum) was measured, while in 1969 the concentration of fine and medium dust, that is, less fly was measured. The factories were divided into three groups according to dust concentration. Comparison between the three factory groups and farfara shows a positive association between the level of dust concentration less fly and the prevalence of cough and phlegm. Since age did not appear to be a significant factor in the prevalence of byssinosis, comparisons between permanent workers in these three groups of factories and farfara workers taken separately were made without age standardization. The overall differences were statistically significant. There was a marked trend showing a positive association between prevalence of byssinosis and level of cotton dust concentration in the factories. The correlation between dust levels and the prevalence of byssinosis was nearly perfect when the time factor was included.     

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.     

Occupational-type exposure tests and bronchoalveolar lavage analyses in two patients with byssinosis and two asymptomatic cotton workers

Summary Two workers suffering from stage III byssinosis and claiming for compensation were examined. Bronchial obstruction was present in one case. MEF_25–75 values were significantly reduced and bronchial hyperreactivity was present in both subjects. Occupational-type exposure tests with cotton dust resulted in significant decreases in arterial oxygen pressure for more than 2 h and were associated with an obstructive ventilation pattern in one of the patients. Prolonged hypoxemia which is not paralleled by lung function changes is probably typical for byssinosis patients since we have never seen this in inhalative challenge tests with various environmental antigens and other occupational substances including flour dust. No specific IgE or IgG antibodies could be detected. In the two patients a hitherto unknown significant increase in CD23+ lymphocytes and granulocytosis were detected by bronchoalveolar lavage (BAL). Corresponding investigations in two cotton workers without any evidence of byssinosis revealed neither lung function changes after the exposure test nor striking BAL findings. Our results demonstrate the diagnostic value of specific challenge tests and BAL investigations in patients suffering from byssinosis, which is often difficult to diagnose.     

BYSSINOSIS IN CARDROOM WORKERS IN SWEDISH COTTON MILLS

The prevalence of byssinosis and chronic respiratory symptoms was studied in 117 workers in four Swedish cotton mills. Changes of forced expiratory volume in 0·75 sec. (F.E.V._0·75) during a Monday and a Wednesday were assessed in 64 male workers in four cardrooms in these mills. Dust sampling was performed with weighed millipore filters.

Prevalences of byssinosis as judged from the workers' histories were 68%, 55%, 44%, and 25% in the four mills; the lowest prevalence of 25% was found in a mill spinning both high grade cotton yarn and rayon. Among 67 workers in the mills having a byssinosis prevalence of 68% and 55%, 60% were non-smokers, 70% had chronic cough, and 27% had chronic dyspnoea. The F.E.V._0·75 decreased on Monday in workers who gave a history of Monday dyspnoea, and to a lesser degree, but still significantly, in those who did not.

In spite of marked differences in fine dust (i.e., dust smaller than 2 mm. diameter) concentrations in the four cardrooms, no significant relations between dust content, byssinosis prevalence, and F.E.V._0·75 changes on Monday could be demonstrated.

The prevention and treatment of byssinosis is discussed. Workers at risk should receive a periodical medical examination including at least a spirographical pulmonary function test at intervals of one year or less.

     

The health investigation of cotton textile workers in Beijing

This study reports findings from a survey of byssinosis among 289 cotton workers in certain cotton textile mills in Beijing. Incidence of byssinosis was 4.2% (12 cases). It decreased with a lower concentration of cotton dust and increased with yearly increment of cotton dust exposure. An elevation in body temperature over 37 degrees C was present among 14.2% of the workers on the first working day after rest. Acute lung function decrement was related to high dust concentration in the rooms. The higher the dust concentration in the rooms, the more evident was the chronic lung function decrement. Chronic bronchitis in cotton workers was higher than in controls. Incidence of byssinosis in smoking cotton workers was higher than in nonsmoking cotton workers.     

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.     

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.

     

Byssinosis in the Egyptian Cotton Industry: Changes in Ventilatory Capacity during the Day

A study in Egypt of 99 male cotton workers in a cotton ginnery and spinning mill, and of a control group of 12 power station workers, showed that the groups exposed to cotton dust had significantly greater falls in indirect maximum breathing capacity (I.M.B.C.) during the shift than groups not exposed to dust. Long-term effects of exposure to cotton dust were studied by examining the I.M.B.C.s measured at the beginning of the shift after adjustment to allow for differences in age and sitting height. The adjusted mean value for those with byssinosis was 10·1 litres/min. lower than for normal cotton workers and 19·6 litres/min. lower than for the power station workers. Four men were judged by their breathlessness on slight exertion and low ventilatory capacities to be seriously disabled with byssinosis.

In four other mills, all spinning similar types of cotton, changes in I.M.B.C. during the shift correlated highly with dust concentrations and indicated a safe level of dustiness of 1 mg./m.³ (total dust) at which the effects on ventilatory capacity were minimal.

     

Role of histamine in the aetiology of byssinosis. I Blood histamine concentrations in workers exposed to cotton and flax dusts

The formation or the accumulation, or both, of histamine in the lungs may be potentiated by agent(s) present in cotton dust at higher level(s) than in flax dust and negligible in cottonseed dust. It has been suggested that such potentiation may be due to the activation of the ability of the lung to produce histamine and/or produce or recruit mast cells; this may present an acceptable explanation of the mechanism by which the propagation of the chronic effect of the dust proceeds in cotton and flax workers. Histamine accumulated in the lung over the weekend is released on exposure to dust causing the symptoms of byssinosis. The difference in the rate of histamine metabolism relative to the rate of histamine formation in byssinotic subjects leads to a more prolonged histamine accumulation than in symptom free subjects, with the consequent appearance of the symptoms of byssinosis. Continuous exposure to dust, without weekend interruption, leads to equivalent rates of histamine formation and metabolism with non-considerable histamine accumulation in the lungs and consequent absence of the symptoms of byssinosis.     

A comparative study of respiratory function in female non-smoking cotton and jute workers

Valić, F., and Žuškin, E. (1971).Brit. J. industr. Med.,28, 364-368. A comparative study of respiratory function in female non-smoking cotton and jute workers. To compare the effect of cotton and jute dust, respiratory symptoms were studied and respiratory function measured in 60 cotton and 91 jute non-smoking female workers of similar age distribution, similar length of exposure to dust, and exposed to similar respirable airborne dust concentrations. Cotton workers had a significantly higher prevalence of byssinosis, of persistent cough, and of dyspnoea (P < 0·01) than jute workers. Among cotton workers 28·3% were found to have characteristic symptoms of byssinosis, whereas none was found among jute workers.

Exposure to cotton but also to jute dust caused significant reductions of FEV_1·0, FVC, and PEF (P < 0·01) over the first working shift in the week. Functional grading of jute and cotton dust effects has shown that about 30% of cotton workers had functional grades F1 and F2, while only 13% of jute workers were found in the same grades (F1). It is concluded that cotton dust may be considered more active than jute though the latter cannot be considered inactive.

     

Role of histamine in the aetiology of byssinosis. I Blood histamine concentrations in workers exposed to cotton and flax dusts.

The formation or the accumulation, or both, of histamine in the lungs may be potentiated by agent(s) present in cotton dust at higher level(s) than in flax dust and negligible in cottonseed dust. It has been suggested that such potentiation may be due to the activation of the ability of the lung to produce histamine and/or produce or recruit mast cells; this may present an acceptable explanation of the mechanism by which the propagation of the chronic effect of the dust proceeds in cotton and flax workers. Histamine accumulated in the lung over the weekend is released on exposure to dust causing the symptoms of byssinosis. The difference in the rate of histamine metabolism relative to the rate of histamine formation in byssinotic subjects leads to a more prolonged histamine accumulation than in symptom free subjects, with the consequent appearance of the symptoms of byssinosis. Continuous exposure to dust, without weekend interruption, leads to equivalent rates of histamine formation and metabolism with non-considerable histamine accumulation in the lungs and consequent absence of the symptoms of byssinosis.     

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。     

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.     

Respiratory symptoms and cotton dust exposure; results of a 15 year follow up observation

Aims: To determine chronic effects of long term exposure to cotton dust and endotoxin on incidence of respiratory symptoms and the effect of cessation of exposure.

Methods: Respiratory health in 429 Chinese cotton textile workers (study group) and 449 silk textile workers (control group) was followed prospectively from 1981 to 1996. Byssinosis, chest tightness, and non-specific respiratory symptoms were assessed by means of identical standardised questionnaires at four time points. Exposures to cotton dust and endotoxin were estimated using area samples collected at each survey. Incidence and persistence of symptoms were examined in relation to cumulative exposure and exposure cessation using generalised estimating equations (GEE).

Results: Among cotton workers, the cumulative incidence of byssinosis and chest tightness was 24% and 23%, respectively, and was significantly more common in smokers than in non-smokers. A high proportion of symptoms was found to be intermittent, rather than persistent. Among silk workers, no typical byssinosis was identified; the incidence of chest tightness was 10%. Chronic bronchitis, cough, and dyspnoea were more common and persistent in the cotton group than in the silk group. Significantly lower odds ratios for symptoms were observed in cotton workers who left the cotton mills; risk was also related to years since last worked. Multivariate analysis indicated a trend for higher cumulative exposure to endotoxin in relation to a higher risk for byssinosis.

Conclusion: Chronic exposure to cotton dust is related to both work specific and non-specific respiratory symptoms. Byssinosis is more strongly associated with exposure to endotoxin than to dust. Cessation of exposure may improve the respiratory health of cotton textile workers; the improvement appears to increase with time since last exposure.

     

Diurnal Variation in Ventilatory Capacity: An Epidemiological Study of Cotton and other Factory Workers employed on Shift Work

The change in F.E.V._0·75 during a working shift was studied in a random sample of 473 men employed in three cotton mills in The Netherlands working a three-shift system. Results were also obtained for 198 men, not exposed to industrial dust, who were working in a biscuit factory and two textile factories in the same area. The men were seen only during the shift on which they were working at the time of the study.

Men with byssinosis gave a typical picture of the effects of cotton dust on susceptible workers: a generally low F.E.V. with a marked reduction during the shift; –0·16 l. on the early morning shift, and –0·25 l. and –0·33 l. respectively on the afternoon and night shifts.

Men without byssinosis in the card and blow rooms showed mean changes in F.E.V. during the shift similar to those of men working in the spinning room: a slight rise in the early morning shift of +0·02 l. followed by a fall in both afternoon and night shifts in the region of –0·10 litres. This pattern of change was also found among the workers in the non-dusty factories. The rise in the early shift cannot be explained by the clearing of mucus from the air passages; cotton workers without respiratory symptoms and men in the non-dusty factories who did not produce sputum still showed an increase in F.E.V. during the early shift, though less marked than that of men with respiratory symptoms or who produced phlegm.

The evidence suggests that a diurnal variation in lung function exists and should be taken into consideration both in epidemiological studies and when ventilatory capacity tests are used in periodic medical examinations.

     

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.     

Differential Aerosol Challenge Studies in Byssinosis

Cotton textile mill workers with conditions diagnosed as byssinosis or not byssinosis by a modified Medical Research Council (MRC) questionnaire were challenged with extracts of cotton dust fractionated by filter membrane dialysis, and volatilization. Byssinotic subjects responded with a significant decrease in FEV_1.0 and with clinical symptoms to the inhalation of whole raw cotton extract and nonvolatile, nondialyzable cotton extract compared to saline, volatile extract, and dialyzable extract. Subjects without byssinosis responded the same to saline as to all other extracts. Comparison of responses of byssinotic and nonbyssinotic subjects showed no statistically significant differences with any extract. It was concluded that the active agent in cotton dust is water soluble, filterable at 0.22μ, nonvolatile at 40C, and nondialyzable but may not be active only in that group of patients identified as byssinotic by questionnaire.     

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.