Respiratory response in simultaneous exposure to flax and hemp dust

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 FEV_1·0 and ˙V_max 50% VC on Monday were recorded in subjects with and without byssinosis with a significantly larger mean reduction in byssinotics (FEV_1·0, P < 0·01; ˙V_max 50% VC, P < 0·05). ˙V_max 50% VC proved to be a more sensitive test for detecting acute effects of vegetable dust than FEV_1·0. 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.     

Byssinosis, respiratory symptoms and spirometric lung function tests in Tanzanian sisal workers

ABSTRACT Byssinosis and other respiratory symptoms and acute and chronic changes in FVC and FEV_1·0 were investigated in 77 workers in sisal spinning and 83 workers in sisal brushing departments in six Tanzanian sisal factories. Although the prevalence of byssinosis in spinning departments was found to be low (5·2%), it was very high in brushing departments (48·2%). Workers in brushing were exposed to sisal dust for a significantly longer period (11·77 ± 7·3 years) compared to workers exposed to sisal in spinning (2·85 ± 2·56 years). Although the number of smokers in brushing (42%) was similar to that in spinning (37%), smokers were more prone to byssinosis than were non- or ex-smokers after standardisation for duration of exposure. We were unable to measure dust levels in this study, but dust levels in spinning and brushing are cited from previous studies. These confirm our impression that the dust level in spinning is higher than that in an average cotton carding department and far higher in brushing than in spinning. Acute falls in FVC and FEV_1·0 were found during the work shift. The extent of the fall in FEV_1·0 correlated well with the severity of byssinosis; 75% of the workers with grade II byssinosis and 33% of those with grade ½ + I were found to have acute falls in FEV_1·0 greater than 0·2 litres. However some workers, 10% in spinning and 33% in brushing, who denied symptoms of byssinosis, were also found to have acute falls in FEV_1·0. Some workers had slight or severe chronic ventilatory impairment from dust (FEV_1·0 less than 80%, or less than 60% of the respective predicted values), and these workers were mostly from the brushing department. The prevalence of chronic cough and chronic bronchitis was found to be negligible in workers in the spinning and in the brushing departments: 9·6% had a chronic cough and 12% had chronic bronchitis. It is concluded that a high prevalence of byssinosis associated with chronic and acute changes in FVC and FEV_1·0 occurs in the brushing departments of sisal factories, and that this is related to lengthy exposure, high dust level and smoking.     

Byssinosis among Winders in the Cotton Industry

In a mill spinning coarse cotton the prevalence of byssinosis and other respiratory symptoms, and the F.E.V._1·0, were measured in a group of 29 men and 117 women employed in the winding room. All the men and 95% of the women at risk were included.

Dust concentrations, measured with a modified Hexhlet at various work points in the winding room, ranged from 1·65 to 6·05 mg./m.³ total dust. These concentrations are higher than 1·0 mg./m.³, which is the threshold limit value for cotton dust recommended by the American Conference of Governmental Industrial Hygienists. The mean dust concentration was 3·48 mg./m.³ compared with 2·85 mg./m.³ in the card room of the same mill.

The prevalence of byssinosis was 18·8% among the women and 13·8% among the men. A comparison among the women showed that those with symptoms of byssinosis had, on the average, significantly lower F.E.V.s than women of similar age without such symptoms. Four women and one man with moderately severe symptoms of byssinosis showed evidence of permanent respiratory disability with effort intolerance and a substantial diminution in F.E.V._1·0. Further studies should be carried out in other winding rooms because, if these findings are repeated elsewhere, they would indicate the necessity for medical surveillance, dust control, and extending the compensation scheme to include winding room workers.

     

A study of rope workers exposed to hemp and flax

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.

     

Byssinosis in the Cotton Industry of Egypt

An epidemiological investigation in 11 ginneries representing the ginning industry in Egypt demonstrated the existence of byssinosis among 38·4% of the workers. Studies of two pressing plants and two card-rooms in Alexandria showed a prevalence of byssinosis of 52·6% and 26·6% respectively. The ages of those exposed and the duration of exposure were considered in relation to the prevalence of byssinosis, and it appears that a short duration of exposure in ginning may result in early manifestations of byssinosis at a relatively young age. The interruption of exposure due to seasonal activity in ginning and partially in pressing resulted in a higher proportion of workers with the early stages of the disease. This contrasted with results in carding where exposure is continuous, and a higher proportion of workers have later stages of the disease. This suggests a delay in the progress of the disease due to periodic interruption of exposure.

The comparison between the prevalence of byssinosis and that of chronic bronchitis has shown that these diseases are not necessarily associated, although additional stress due to dust exposure in chronic bronchitis is not denied.

     

Dust exposure in manual flax processing in Egypt.

Manual flax processing originated in Egypt in 2 000 BC. In the present study a representative sample of the workers involved in this trade, where flax is processed in small workshops or homes, was examined, and their dust exposure was evaluated. The study showed that workers handling and processing flax are exposed to high concentrations of dust; the levels of dust at hackling and combing are considerably higher than at batting and spinning. Byssinosis prevailed in 22-9% of the examined workers, and 18-4% of them had their forced expiratory volume in one second reduced by more than 10% at the end of the first morning work period (4 hours) of the week. Both the rates and the grades of these syndromes increased with duration of exposure. Smoking appeared to be one of the important contributory factors in the production of byssinosis. The relationship between dust concentration and prevalence of byssinosis seems to be curvilinear.     

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.

     

Byssinosis, Chronic Bronchitis, and Ventilatory Capacities in Workers Exposed to Soft Hemp Dust

A study was made of 93 women and 13 men employed in the spinning department of a factory in Yugoslavia processing soft hemp (Cannabis sativa). There were seven occupational groups, with average concentrations of total airborne hemp dust ranging from 2·9 mg./m.³ to more than 19·5 mg./m.³. Thirtyeight women and 11 men, employed in other departments of the factory with average total dust concentrations below 1·0 mg./m.³, were studied as controls.

In the spinning department 40·6% of the workers had byssinosis and 15·1% had chronic bronchitis (defined as persistent cough and phlegm on most days for as much as three months each year during the last two years). None of the controls suffered from either disease.

After adjustment for age, sitting height, and sex, the F.E.V._0·75 and F.V.C. measured at the beginning of the shift were used to assess the long-term effects of hemp dust on the ventilatory function of the lung. The age-adjusted ratio F.E.V._0·75/F.V.C. was also used. A comparison between the control group and the seven exposed groups showed no meaningful association between ventilatory function and present levels of dust exposure, but byssinotics with chronic bronchitis had a mean age-adjusted F.E.V._0·75/F.V.C. ratio significantly lower than that of workers with neither disease (P<0·05).

Acute effects of hemp dust, measured by the change in F.E.V._0·75 and F.V.C. during the shift, were considerable. There were marked reductions in the mean F.E.V._0·75 and F.V.C. during the shift in all the occupational groups exposed to high concentrations of dust. Byssinotics with chronic bronchitis had a significantly greater mean decrease in F.E.V._0·75 during the shift than the byssinotics without chronic bronchitis, and the workers with neither disease (P<0·02).

There is no doubt that the dust of Cannabis sativa hemp can cause byssinosis and at least temporary impairment of ventilatory function, varying in severity according to the level of dust exposure and the presence of respiratory disease.

     

Effects of different vegetable dust exposures

Valić, F., and Žuškin, E. (1972).Brit. J. industr. Med.,29, 293-297. Effects of different vegetable dust exposures. In order to establish the rank of biological activity of vegetable dusts, five groups of non-smoking female workers exposed to similar concentrations of hemp, flax, cotton, sisal, and jute airborne dust, respectively, were compared as to the prevalence of byssinosis, chronic respiratory symptoms, and one-second expiratory volume changes over the Monday shift. The groups were selected in such a way as to differ in the distribution of age and length of exposure to the respective dust as little as possible.

The prevalence of byssinosis in hemp and flax workers was approximately equal (44% and 43% respectively), in cotton workers it was considerably lower (27%), while no byssinosis was caused by either sisal or jute dust. The highest prevalence of other chronic respiratory symptoms was recorded in hemp workers (39%), followed by flax (36%) and cotton workers (27%), while in sisal (13%) and jute workers (13%) it was the lowest.

Significant mean FEV_1·0 reductions over the shift were recorded in all the groups of textile workers with the largest reductions in hemp workers (19%) followed by flax (11%), cotton (8%), sisal (7%), and jute workers (5%). The application of orciprenaline before the shift diminished the mean acute FEV_1·0 falls over the work shift in all the groups studied.

     

Preprocessing cotton to prevent byssinosis

Merchant, J. A., Lumsden, J. C., Kilburn, K. H., Germino, V. H., Hamilton, J. D., Lynn, W. S., Byrd, H., and Baucom, D. (1973).British Journal of Industrial Medicine,30, 237-247. Preprocessing cotton to prevent byssinosis. A fundamental approach of cleaning or deactivating cotton prior to manufacturing has long been advocated to prevent byssinosis, but no trial had been conducted to test the feasibility of such an approach. In the study described, it was possible to be directed by both biological observations and the results of manufacturing trials.

An exposure chamber was built in a cotton textile mill which had been previously studied as part of a large cross-sectional survey. The chamber was provided with an independent air conditioning system and a carding machine which served as a dust generator. Sixteen subjects, who had shown reductions in expiratory flow rate with exposure to cotton dust, were chosen to form a panel for exposure to raw cottons and cottons which had been preprocessed by heating, washing, and steaming. Indicators of effects were symptoms of chest tightness and/or dyspnoea, change in FEV_1·0, and fine dust levels over 6 hours of exposure.

Exposure of the panel to no cotton dust resulted in no change in FEV_1·0 and served as the control for subsequent trials. Exposure to strict middling cotton resulted in a byssinosis symptom prevalence of 22%, a significant decrement in FEV_1·0 of 2·9%, and a fine dust level of 0·26 mg/m³. Exposure to strict low middling cotton resulted in a byssinosis symptom prevalence of 79%, a decrement in FEV_1·0 of 8·5%, and a fine dust level of 0·89 mg/m³. Oven heating strict low middling cotton resulted in a byssinosis symptom prevalence of 56% and a relatively greater drop in FEV_1·0 of 8·3% for 0·48 mg/m³ of fine dust. Washing the strict low grade cotton eliminated detectable biological effects with a symptom prevalence of 8%, an increase of 1·4% in FEV_1·, and a dust level of 0·16 mg/m³, but the cotton proved to be difficult to process. As an alternative method, strict low middling cotton was steamed initially in large dyeing vats, on a conveyor, in an autoclave, and in a modified yarn dyeing apparatus or `pipe' steamer. Of these methods, autoclaving cotton was the most successful, reducing symptom prevalence to 8%, the drop in FEV<sub>1·0</sub> to 0·4%, and the dust level to 0·23 mg/m<sup>3</sup>. Development of a high capacity cotton steamer based on the small `pipe' steaming model resulted in a symptom prevalence of 8%, a decrement in FEV_1·0 of 0·8%, and a mean dust level of 0·27 mg/m³. Regressions calculated from raw and high capacity steaming trials indicate that at low dust levels steamed cotton dust was roughly one half as biologically active as raw cotton dust.

     

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.

     

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.

     

BYSSINOSIS IN COTTON GINNERIES IN GREECE

The prevalence of byssinosis in a sample of cotton ginnery workers in Greece was investigated. The respiratory symptoms, F.E.V._1·0, and V.C. of 70 male ginnery workers were recorded. No case of clinical byssinosis was found, but a statistically significant relationship exists between years of exposure to cotton dust and impairment of lung function. On the contrary no significant relationship exists between smoking and lung function, or between sputum production and lung function. The findings suggest the hypothesis that the cotton dust may exert, in the case of a prolonged exposure, a chronic deleterious action without producing the typical symptoms of clinical byssinosis.     

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.

     

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.

     

Seasonal exposure to dust in flax processing in Egypt.

Previous evidence suggested that interruption of worker's exposure to flax dust may lead to severe symptoms of byssinosis on their return to work. In the present study, the prevalence and severity of byssinosis was studied in a sample of flax workers (n=577) who had been exposed to dust for six months each year. Byssinosis prevailed in 36.9% of them, and 32.3% of them had their FEV 1.0 sec reduced 10% at the end of the first morning work period (4 to 6 hours) of the week. Both syndromes were higher among seasonal workers than what would be predicted if they were pemanently exposed to flax dust. A hypothesis has been presented to interpret this finding.     

CHANGES IN VENTILATORY CAPACITY IN A GROUP OF FLAX WORKERS IN NORTHERN IRELAND

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.

     

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.

     

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.

     

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.