A survey of 255 workers in four cottonseed crushing mills included a respiratory health questionnaire, allergy skin testing, and measurements of lung function over the Monday working shift. Atopy was defined as having two or more positive weal reactions to common inhalant antigens. Categories of exposure to dust were based on the stage of milling, and one category contained workers with continuous exposure to cotton dust derived from linters, the cotton fibres adherent to cottonseed. Atopy and exposure to dust were found to have significant interaction: large mean declines in FEV1 and FEF 25-75 occurred only in the workers exposed to linter dust who were also atopic. Skin-testing surveys in cotton textile mills have concentrated on specific cotton antigen reactivity and its first-order relations to symptoms. Our results indicate a need to identify atopic workers, and to search for interactions between atopy and other variables that may influence acute changes in expiratory flow rates.
The prevalence of byssinosis, respiratory symptoms, acute changes of ventilatory capacity over the shift, and chronic changes of ventilatory capacity were studied in two groups of non-smoking female workers exposed to practically identical concentrations of the same type of cotton dust but for very different periods of time (16 and 4 years respectively). The prevalence of non-specific respiratory symptoms increased with the duration of exposure to cotton dust only in the subjects with byssinosis. Exposure to cotton dust caused significant reductions over the shift of the mean FEV1.0, FVC and PEF in all the groups of cotton workers examined. In byssinotics the reduction in ventilatory capacity was considerably greater in subjects with longer than in those with shorter exposure to cotton dust, while in non-byssinotics the response was approximately equal in the two groups. Inhalation of a bronchodilator at the end of the shift restored ventilatory function to its pre-shift values except in byssinotics with a longer duration of exposure to cotton dust. Chronic changes of ventilatory capacity developed only in subjects with a longer exposure to cotton dust and were common in the byssinotics.
Valić, F., and Žuškin, E. (1973).British Journal of Industrial Medicine,30, 381-384. Pharmacological prevention of acute ventilatory capacity reduction in flax dust exposure. The protective effect of the preshift application of a bronchodilator (orciprenaline), an antihistamine drug (diadril), and ascorbic acid on flax-induced acute bronchoconstriction was studied in 13 byssinotic and 7 non-byssinotic female workers exposed to airborne fibres of biologically retted flax. Orciprenaline was applied by inhalation, while diadril and ascorbic acid were given orally. All the three drugs exerted a significant preventive effect, diminishing the acute fall of ventilatory capacity during the shift. The fall in forced expiratory volume (FEV1·0) was reduced by 50% and the fall in maximal flow rate at 50% vital capacity (V̇max 50% VC) by over 65%.
Respiratory function was studied in five groups of tea workers employed in processing different types of tea. The prevalence of almost all chronic respiratory symptoms was significantly higher in workers processing dog-rose, sage, and gruzyan tea than in control workers. During the Monday workshift there was a significant mean acute decrease in maximum expiratory flow rates at 50% vital capacity (range: 4.1-8.8%) and at 25% VC (range: 7.8-21.8%) except in those exposed to camomile. Acute reductions in forced expiratory volume in one second were considerably smaller and mostly not significant. Mean acute reductions on Wednesday were similar to those on Monday with no significant differences between preshift Monday and Wednesday data. Acute decreases in flow rates at low lung volumes suggest that the bronchoconstrictor effect of the dust acts mostly on smaller airways. Preshift administration of disodium cromoglycate significantly diminished acute reduction in flow rates except in workers processing Indian tea. A comparison of Monday preshift values of ventilatory capacity in tea workers with those in controls indicates that exposure to tea dust may, in some workers, lead to chronic respiratory impairment.
Smith, G. F., Coles, G. V., Schilling, R. S. F., and Walford, Joan (1969).Brit. J. industr. Med.,26, 109-114. A study of rope workers exposed to hemp and flax. Respiratory symptoms and ventilatory capacities were studied in 54 men and 22 women exposed to the mixed dusts of hemp and flax in an English rope factory. The preparers and most of the spinners were exposed on average to concentrations of 1·7 mg./m.3 total dust and 0·5 mg./m.3 fine dust. Those employed on subsequent processes had lower exposures at concentrations of 0·5 mg./m.3 total dust and 0·1 mg./m.3 fine dust.
Six men, all in the high exposure group, had symptoms of byssinosis. After adjustment for age and standing height there was no statistically significant difference in the forced expiratory volume (F.E.V.1·0) between those in high dust concentrations and those in low concentrations; neither was there a significant difference between the ventilatory capacities of men with and without byssinosis.
This study shows that byssinosis is an occupational hazard confined to male workers in this factory. It does not appear to be a very serious problem and will diminish with the increasing use of synthetic materials instead of natural fibres.
Respiratory function was studied in three groups of workers employed in processing coffee. The prevalence of almost all chronic respiratory symptoms was significantly higher in coffee processors than in control workers. In each group during the Monday work shift there was a significant mean acute decrease in the maximum expiratory flow rate at 50% vital capacity (VC), ranging from 4.0% to 8.7%, and at 25% VC, ranging from 6.0% to 18.5%. Acute reductions in FEV1.0 were considerably lower, ranging from 1.3% to 2.8%. On Thursdays the acute ventilatory function changes were somewhat lower than on Mondays. Acute decreases in flow rates at low lung volumes suggest that the bronchoconstrictor effect of the dust acts mostly on smaller airways. Administration of Intal (disodium cromoglycate) before the shift considerably diminished acute reductions in flow rates. A comparison of Monday pre-shift values of ventilatory capacity in coffee workers with those in controls indicates that exposure to dust in green or roasted coffee processing may lead to persistent loss of pulmonary function.
Žuškin, E., and Valíc, F. (1973).British Journal of Industrial Medicine,30, 375-380. Respiratory response in simultaneous exposure to flax and hemp dust. The effect of exposure to high concentrations of mixtures of hemp and flax dust was studied in 124 workers in two textile mills (mill A: 65-70% hemp and the rest flax, mean dust concentration 13·9 mg/m3; and mill B: about 35% hemp and the rest flax, mean dust concentration 15·8 mg/m3). A high prevalence of byssinosis was found in both mills (80% in mill B; 46·8% in mill A) after a mean exposure of no more than 13 years. In both mills, byssinotics had a higher prevalence of all chronic respiratory symptoms than non-byssinotics. This difference was more pronounced in mill A. Forty-eight percent of byssinotic women and 43% of byssinotic men had byssinosis of grade 2 or 3. Significant mean acute reductions in FEV1·0 and ˙Vmax 50% VC on Monday were recorded in subjects with and without byssinosis with a significantly larger mean reduction in byssinotics (FEV1·0, P < 0·01; ˙Vmax 50% VC, P < 0·05). ˙Vmax 50% VC proved to be a more sensitive test for detecting acute effects of vegetable dust than FEV1·0. The acute respiratory response of the subjects exposed to similar concentrations of flax and mixtures of two different proportions of flax and hemp dust was found to be equal.
BACKGROUND: Exposure to cotton is known to produce a specific occupational disease known as byssinosis. A large population of textile workers was investigated to determine whether such exposure was also associated with chronic bronchitis once other possible aetiological factors had been accounted for. METHODS: A total of 2991 workers were investigated for the presence of symptoms compatible with chronic bronchitis. An MRC adapted respiratory questionnaire and MRC definition of chronic bronchitis were used for diagnostic labelling. Current and lifetime exposure to dust was estimated by personal and work area sampling, and the use of records of retrospective dust levels previously measured over the preceding 10 years. Airborne endotoxin exposure was measured using a quantitative turbidometric assay. Lung function tests were performed to measure forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). A control group of workers exposed to man-made fibre textiles was identified. The comparative prevalence of chronic bronchitis in the two populations was assessed, allowing for sex, age, smoking habit, and ethnic origin. Two case referent studies were also performed; cases of chronic bronchitis were separately matched with controls from the cotton and control populations to determine the effect of the symptomatic state on lung function. RESULTS: After controlling for smoking (pack years), workers in a cotton environment were significantly more likely to suffer from chronic bronchitis and this was most marked in workers over 45 years of age (odds ratio 2.51 (CI 1.3 to 4.9); p < 0.01). Regression analysis of all possible influencing parameters showed that cumulative exposure to cotton dust was significantly associated with chronic bronchitis after the effects of age, sex, smoking, and ethnic group were accounted for (p < 0.0005). In the intra-cotton population case control study a diagnosis of chronic bronchitis was associated with a small decrement in lung function compared with controls: percentage predicted FEV1 in cases 81.4% (95% CI 78.3 to 84.6), controls 86.7% (84.9 to 88.5); FVC in cases 89.9% (95% CI 87.0 to 92.9), controls 94.6% (92.8 to 96.4). After controlling for cumulative past exposure and pack years of smoking the effect of the diagnostic state remained significant for both FEV1 (p < 0.01) and FVC (p < 0.05). CONCLUSIONS: Chronic bronchitis is more prevalent in cotton workers than in those working with man-made fibre and exposure is additive to the effect of smoking. The diagnosis of chronic bronchitis is associated with a small but significant decrement in lung function.
One-second forced expiratory volume (F.E.V.1·0) and forced vital capacity (F.V.C.) were measured before starting work in five flax hacklers with symptoms of grade II byssinosis and in five matched controls. Similar measurements were taken in each group at the end of the day shift.
A significant (P < 0·05) decline in F.E.V.1·0 was observed in the hacklers during the day on Monday, Tuesday, Wednesday, and Friday. The F.V.C. also declined significantly in the hacklers on Monday, Tuesday, and Wednesday. In the control group, ventilatory function tended to decline during the day, but this was significant only for F.E.V.1·0 on Monday. The reason for this is discussed.
Variations in the dust concentrations in the mill and in outdoor air pollution are shown to be unlikely to have affected the findings.
Morning values of F.E.V.1·0 and of F.V.C. were consistently lower in the byssinotic group than in the matched controls, suggesting that the inhalation of flax dust causes not only daily variations in lung function but longer-term impairment of ventilatory capacity as well. Additional evidence is given for this conclusion from two other studies.
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 FEV1 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 FEV1 change for cotton and silk workers, respectively. Among male cotton workers, smokers gained more FEV1 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.
respiratory disease; environmental health; cotton textile workers; endotoxin exposure; occupational health
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.
Aims: To examine early adverse pulmonary effects of exposure to cotton dust, and to identify potential risk factors, including atopy for pulmonary responses to cotton dust.
Methods: Spirometry, methacholine challenge testing, and questionnaire; performed among 101 non-smoking newly hired textile workers at baseline (prior to starting work), and at 3, 12, and 18 months after starting work. Concentrations of airborne cotton dust in various work areas were measured at each follow up survey using vertical elutriators.
Results: The incidence of non-specific respiratory symptoms was 8% at three months, then diminished afterwards. Substantial acute cross shift drops in FEV1 at each follow up survey, and longitudinal declines in FVC and FEV1 after 12 months of exposure were observed. Airway responsiveness to methacholine increased with follow up time, and was more pronounced among atopics. Increasing airway responsiveness was strongly correlated with cross shift drops in FEV1. In addition, one or more respiratory symptoms at three months was significantly, and pre-existing atopy marginally significantly, associated with cross shift drops in FEV1 after adjusting for other covariates and confounders.
Conclusion: Results suggest that non-specific respiratory symptoms, decreasing lung function, and increasing airway responsiveness are early pulmonary responses to cotton dust. In addition, the occurrence of respiratory symptoms and increasing airway responsiveness, as well as atopy, may be important predictors for acute changes in lung function among cotton textile workers.
Four cottonseed mills in the southern United States contained high levels of total and respirable dust. A survey of 172 workers showed low prevalences of byssinosis (2-3%) and chronic bronchitis (4%). Mean baseline (out of dust) lung function values were normal. Mean functional declines over the working shift were present on Monday and absent on Friday, indicating an acute bronchoconstrictor response. Despite limitations in translating measured dust levels into estimates of individual exposures, the overall dose-response relationship seems to differ from that found in the cotton textile industry.
Workers from cotton mills were exposed to cotton dust during carding in an experimental cardroom. Cotton from different geographical locations with varying amounts of endotoxin were used. Exposure levels ranged from 0.6 to 3.6 mg dust/m3 (from a vertical elutriator) and from 0.1 to 8.0 micrograms/m3 of endotoxin. No relationship was found between the decrease in FEV1 over the workshift and the amount of airborne dust. Airborne endotoxin correlated with the decrease in FEV1 and the increase in blood neutrophils. The FEV1 decrease was more pronounced among smokers. The data suggest that the amount of airborne endotoxin determines the risk for development of the acute symptoms in the byssinosis syndrome.
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.
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.
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.
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 FEV1·0, 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.
Popa, V., Gavrilescu, N., Preda, N., Teculescu, D., Plecias, M., and Cîrstea, M. (1969).Brit. J. industr. Med.,26, 101-108. An investigation of allergy in byssinosis: sensitization to cotton, hemp, flax, and jute antigens. The authors investigated allergy to cotton, hemp, flax, and jute in 41 subjects with byssinosis. In contrast with immediate skin reactions, which were seldom observed, delayed reactions were nearly always present. The incidence of positive skin tests in byssinosis was similar to that observed in all textile workers. Inhalation tests with textile allergens were negative in all but four subjects who also had a concomitant bronchial asthma. Fifteen out of 31 subjects with byssinosis had positive inhalation tests to acetylcholine but only one of the 13 tested had a positive response to the inhalation of textile macerate. Haemagglutinating antibodies to low titres could be observed in byssinosis as well as in chronic bronchitis, in bronchial asthma, and in the general population. The significance of various types of antibodies existing in byssinosis is further discussed. The authors stress the need to standardize textile allergens.
The same plan of investigation as was used in a previous study of jute workers (Gandevia and Milne, 1965) has been applied to a survey of 50 workers in the blowroom and carding and spinning area of a Sydney cotton mill. Significant decreases in ventilatory capacity were recorded on Friday, Monday, and the following Thursday, with, on the average, complete `overnight' recovery, as indicated by similar morning values. Slightly, but not significantly, greater differences were observed in seven subjects with mild byssinotic symptoms and in five subjects with an observed productive cough on request. No effect of sex, shift, or history of cough and sputum was demonstrable. By contrast with the jute workers, no influence of smoking habit was apparent. The larger decreases in ventilatory capacity were observed in those with the higher F.E.V.1·0:F.V.C. ratios, whereas the reverse trend was noted in the jute workers. The occurrence of significant large decreases in those employed in the industry for less than a month, in conjunction with other evidence, suggests that a factor of `self-selection' may be operative among cotton employees in this country and may be related to the apparently low prevalence of clinically important byssinosis. Attention is drawn to two different patterns of change of ventilatory capacity over a week in subjects exposed to dusts sometimes associated with symptoms of byssinosis; the relationship of these changes and of chronic bronchitis to the development of clinical byssinosis is discussed.
Cardiopulmonary exercise testing (CPET) plays an important role in the assessment of functional capacity in patients with interstitial lung disease. The aim of this study was to identify CPET measures that might be helpful in predicting the vital capacity and diffusion capacity outcomes of patients with thoracic sarcoidosis. A longitudinal study was conducted on 42 nonsmoking patients with thoracic sarcoidosis (median age = 46.5 years, 22 females). At the first evaluation, spirometry, the measurement of single-breath carbon monoxide diffusing capacity (DLCOsb) and CPET were performed. Five years later, the patients underwent a second evaluation consisting of spirometry and DLCOsb measurement. After 5 years, forced vital capacity (FVC)% and DLCOsb% had decreased significantly [95.5 (82-105) vs 87.5 (58-103) and 93.5 (79-103) vs 84.5 (44-102), respectively; P < 0.0001 for both]. In CPET, the peak oxygen uptake, maximum respiratory rate, breathing reserve, alveolar-arterial oxygen pressure gradient at peak exercise (P(A-a)O2), and Δ SpO2 values showed a strong correlation with the relative differences for FVC% and DLCOsb% (P < 0.0001 for all). P(A-a)O2 ≥22 mmHg and breathing reserve ≤40% were identified as significant independent variables for the decline in pulmonary function. Patients with thoracic sarcoidosis showed a significant reduction in FVC% and DLCOsb% after 5 years of follow-up. These data show that the outcome measures of CPET are predictors of the decline of pulmonary function.
Sarcoidosis; Exercise; Respiratory function tests; Respiratory mechanics
Rationale: Acute airway response, measured as cross-shift change in FEV1, to cotton dust may lead to subsequent chronic loss of lung function in exposed workers.
Objectives: To explore the association between the magnitude and frequency of cross-shift change and chronic loss of FEV1.
Methods: Four hundred eight cotton workers and 417 silk workers from Shanghai textile mills were observed prospectively for 20 years, with cross-shift measurements at baseline and follow-up surveys at approximate 5-year intervals. To account for repeated measures of 5-year change, generalized estimating equations were used to estimate the relationship between the magnitude of cross-shift change in FEV1 (ΔFEV1) and subsequent 5-year annualized change. Linear regression models were used to examine the association between the number of drops in cross-shift FEV1 (ΔFEV1 < 0) and annualized change over the entire study period.
Measurements and Main Results: Exposure to cotton dust was associated with a 10 ml/year decrement in 5-year annualized FEV1 decline. In addition, every 10 ml in ΔFEV1 drop was associated with an additional 1.5 ml/year loss in annualized FEV1 decline. The association between the frequency of drops and annualized decline was stronger for cotton workers than for silk workers over the entire study period.
Conclusions: Cotton workers had larger and more frequent drops, as well as excessive chronic declines in FEV1, than did silk workers. The magnitude and frequency of cross-shift drops were associated with chronic loss in FEV1 over the entire 20-year period examined.
cross-shift FEV1 change; chronic changes in lung function; cotton textile workers; cotton dust; occupational lung disease
Berry, G., McKerrow, C. B., Molyneux, M. K. B., Rossiter, C. E., and Tombleson, J. B. L. (1973).Brit. J. industr. Med.,30, 25-36. A study of the acute and chronic changes in ventilatory capacity of workers in Lancashire cotton mills. A prospective study of workers in 14 cotton and two man-made fibre spinning mills in Lancashire was carried out over a three-year period. A questionnaire on respiratory symptoms was completed at the start of the survey and again two years later. Up to six measurements of ventilatory capacity were made at six-monthly intervals. From these measurements the rate at which the forced expiratory volume (FEV1) was declining (annual decline in FEV) was evaluated for 595 subjects. Six of the mills were visited on Mondays and in 199 operatives the ventilatory capacity was measured at both the beginning and end of the shift to evaluate its acute fall during work (Monday fall in FEV).
The mean annual decline in FEV for cotton workers was 54 ml/year and it was only 32 ml/year for workers in the man-made fibre mills but this lower value was attributable almost entirely to one of the two mills. For the jobs near the carding engines the annual decline was 22 ml/year higher than for speed-frame tenters. The annual decline for cigarette smokers was 19 ml/year greater than for non- and ex-smokers. The annual decline in FEV was not found to be related to symptoms of byssinosis or bronchitis, nor to present dust levels, bioactivity of the dust or air pollution, although the expected effect attributable to byssinosis turned out to be less than that which the survey was designed to detect.
The mean Monday fall in FEV was higher in cotton mills than in man-made fibre mills among those without symptoms of byssinosis and was correlated with present dust levels. For those with symptoms of byssinosis an increased Monday fall was found only in those processing coarse cotton.
For those subjects who completed the respiratory questionnaire on two occasions the chronic and acute changes in FEV were examined in relation to the change in symptoms of byssinosis. No association was found for annual decline in FEV but the Monday fall in FEV was greater for those who developed byssinosis during the survey than for those who remained free of symptoms, and was less for those who lost their symptoms than for those who retained them.
OBJECTIVES—A cross sectional prospective study was carried out among iron foundry workers (exposed) and soft drink bottling and supply company workers (unexposed) to assess their occupational exposure to ambient respiratory dust in their work environment and its effect on their lung function profile.
PARTICIPANTS—Lung function was measured in 81 exposed and 113 unexposed workers. Personal respirable dust concentrations were measured for all the exposed and the unexposed workers. Information on respiratory signs and symptoms was also collected from the participants.
RESULTS—Among the exposed workers, midexpiratory flow (FEF25-75), forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), FEV1/FVC, and FEV1/VC ratios were significantly lower whereas the vital capacity (VC) and forced vital capacity (FVC) were non-significantly higher. Job at the iron foundry was a significant predictor of lung function. Exposure to high concentration of respirable dust at the iron foundry was also a significant predictor. Workers working in high exposure areas (general works, furnace, continuous casting areas, and fabrication workshop) had lower lung function values than workers in medium and low exposure areas. Smoking did not enhance the effects of exposure to dust on lung function.
CONCLUSIONS—Exposure to respirable dust was higher among the iron foundry workers; and among these, general, furnace, rolling mill, and fabrication workers had higher exposures to dust than did workers in continuous casting, the mechanical workshop, and the bottling plant. Job type and exposure to dust were significant predictors of lung function. Implementation of industrial hygiene and proper and efficient use of personal protection equipment while at work could help to protect the respiratory health of industrial workers.
Keywords: lung function; dust exposure; foundry; smoking; personal protection
Occupational exposure to wood dust has been shown to cause several respiratory disorders, such as allergic rhinitis, chronic bronchitis, asthma, sino-nasal adenocarcinoma, and impairment of lung function. The aim of the study was to estimate lung function (in the woodworking industry) among workers employed by wood processing, who run the risk of being expose to wood dust.
The study concerns a group of 70 workers aged 24-55. All the workers underwent general and laryngological examination. A group of 20 workers, working at the positions where dustiness exceeded TLV (threshold limit value) took X-ray of the chest and spirometry. The following parameters were measured: VC, IC, ERV, TV, BF, FEV1, FVC, PEF, MEF25-75, FEV1%FVC, FEV1%VC. The data are presented as means ± SD and the authors applied references values according to ERS guidelines.
The results show that there was no decline in FEV1 (3.7 ± 0.7) and FVC (4.5 ± 0.8). Normal lung function was defined as FEV1/VC ratio ≥0.7. None of the tested workers had obstructive pattern in spirometry. The mean FEV1%VC was 77.1 ± 10.2. These results suggest that wood dust exposure might not lead to significant pulmonary damage.
These data do not corroborate that wood dust plays significant role in lung function impairment. Future studies of respiratory health among workers exposed to wood dust are needed.
lung function; occupational exposure; wood dust; spirometry parameters