Passive cigarette smoke, coal heating, and respiratory symptoms of nonsmoking women in China.

In this study we evaluated data from a sample of 973 never-smoking women, ages 20-40, who worked in three similar textile mills in Anhui Province, China. We compared prevalence rates of respiratory symptoms across homes with and without coal heating and homes with different numbers of smokers. Multiple logistic regression models that controlled for age, job title, and mill of employment were also estimated. Respiratory symptoms were associated with combined exposure to passive cigarette smoke and coal heating. Effects of passive cigarette smoke and coal heating on respiratory symptoms appeared to be nearly additive, suggesting a dose-response relationship between respiratory symptoms and home indoor air pollution from these two sources. The prevalence of chest illness, cough, phlegm, and shortness of breath (but not wheeze) was significantly elevated for women living in homes with both smokers and coal heating.     

Follow-up study of respiratory health of newly-hired female cotton textile workers

BACKGROUND: Numerous studies have investigated adverse effects of exposure to cotton dust on respiratory health, but very limited longitudinal data are available with regard to the early pulmonary response to cotton dust. Moreover, the adverse effects of occupational exposure to cotton dust have been difficult to separate from the confounding effects of smoking. This setting provided a unique opportunity to evaluate early respiratory effects in newly hired and non-smoking female textile workers. METHODS: To identify early pulmonary responses to cotton dust exposure and associated gram-negative bacterial endotoxin, respiratory symptoms and pulmonary function in 225 newly-hired textile workers were assessed at work initiation, and at three and twelve months later. RESULTS: All the workers were females and nonsmokers, with an average age of 18 years. Symptom incidence at three months was 3.6% for usual cough with phlegm, and 6.7% for usual dry cough. Lung function changes were detectable at one year: FEV1 declined by 70 ml and FVC by 124 ml over the year, and workers reporting respiratory symptoms at three months showed a significantly greater cross-shift drop in FEV1 (- 2.3%) than those without the symptoms (- 0.7%). CONCLUSIONS: These results suggest that the occurrence of respiratory symptoms represents the earliest response to cotton dust exposure, followed by lung function changes. Early respiratory symptoms may be a risk factor for subsequent loss of pulmonary function in cotton textile workers.     

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

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

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.     

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.

     

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.     

Immunological findings and respiratory function in cotton textile workers

Summary Immunological parameters were studied in a group of 24 cotton textile workers. These were volunteers from a cohort of 106 (83 women and 23 men) previously studied textile workers. A group of 30 employees from a bottle packing plant served as a control for the immunologic studies. The subgroup of volunteers undergoing immunologic testing did not differ from the original cohort of textile workers in age, sex, smoking history, or prevalence of most chronic respiratory symptoms, nor were there any significant differences in baseline lung function or across-shift changes. The 24 cotton worker volunteers underwent skin testing with extracts of cotton dust and cotton seed. Eight of these 24 (33.3%) had positive tests, and 5 of the 8 had elevated serum immunoglobulin E (IgE) levels. Only one of the 8 skin-test-positive workers had symptoms of byssinosis. Only 1 of 30 control workers' skin tested with cotton extract reacted, and none had an increased serum IgE level (P < 0.01). Both baseline lung function and across-shift changes did not differ between workers with positive and negative skin test reactions or between workers with normal and elevated IgE levels. Additionally, we studied the response in vitro of nonsensitized guinea pig trachea to cotton bract extract and demonstrated a dose-dependent contractile response. These data suggest that while immunological findings are frequent in textile workers, they correlate poorly with respiratory symptoms and function and may not be the basis for the airway obstruction seen in this disease.Supported in part by grant no. YF 733 from the National Institutes of Health, Bethesda, Maryland, USA, grant no. R01 OHO 2593-01A1 from the National Institute of Occupational Safety and Health, Centers for Disease Control, Atlanta, Georgia, USA, and the Henry and Catherine Gaissman Fund, New York, NY, USA     

Respiratory symptoms in Lancashire textile weavers

OBJECTIVES: To investigate a large population of cotton textile weavers for reported respiratory symptoms relative to occupational factors, smoking, and exposure to dust. Cotton processing is known to produce a respiratory disease known as byssinosis particularly in the early processes of cotton spinning. Relatively little is known about the respiratory health of the cotton weavers who produce cloth from spun cotton. By the time cotton is woven many of the original contaminants have been removed. METHODS: 1295 operatives from a target population of 1428 were given an interviewer led respiratory questionnaire. The presence of upper and lower respiratory tract symptoms were sought and the work relatedness of these symptoms determined by a stem questionnaire design. Also occupational and demographic details were obtained and spirometry and personal dust sampling performed. RESULTS: Byssinosis was present in only four people (0.3%). Chronic bronchitis had a moderate overall prevalence of about 6% and was related predominantly to smoking. There were several other work related respiratory symptoms (persistent cough 3.9%, chronic production of phlegm 3.6%, chest tightness 4.8%, wheezing 5.4%, and breathlessness 2.3%). All of these were predicted predominantly by smoking (either past or present), with no consistent independent effect of exposure to dust. Work related eye and nasal symptoms were more common (10.4% and 16.9% respectively). CONCLUSION: Byssinosis is a rare respiratory symptom in cotton weaving. Other work related respiratory symptoms were reported but their presence was predominantly related to smoking with no consistent effects of exposure to dust.

 

     

Factors related to the prevalence of respiratory symptoms in workers in a petrochemical complex

This study was performed to evaluate the prevalence of respiratory symptoms in workers in a petrochemical complex and to elucidate the relationship between the prevalence and work-related factors. A questionnaire was distributed to 5,983 male workers working in a petrochemical complex. As for the respiratory symptoms, cough was present in 2.4%, phlegm in 8.1%, wheezing in 2.8% and shortness of breath in 4.7% of the workers. The factors significantly related to respiratory symptoms were smoking history, wearing of protective devices, handling of substances toxic to the respiratory system, and history of atopy or respiratory disease (p<0.05). The substances toxic to the respiratory system were divided into 4 types, ie., dusts, solvents, metals, and vapors. When the analysis was performed to evaluate the effects of exposure to substance type on respiratory symptoms, the odds ratio of cough was 1.96 times higher in those workers exposed to dusts compared with those not exposed, 2.28 times for exposure to metals, 1.52 times for solvents, and 1.55 times for vapors, all showing significant differences (p<0.05). For phlegm, the odds ratio was 1.08 times higher in those workers exposed to dusts compared with those not exposed, 1.94 times for exposure to metals, 1.70 times for organic solvents, and 1.85 for vapors (p<0.05). For wheezing, the odds ratio was 2.38 times for exposure to dusts; for shortness of breath, it was 2.42 times for exposure to dusts, 2.89 times for metals, 2.10 times for organic solvents, and 2.14 times for vapors, all showing significant differences (p<0.05). In conclusion, work-related factors significantly affected the respiratory symptoms in workers working in the petrochemical complex. Especially, these respiratory symptoms were significantly related to exposure to toxic substances and the wearing of protective devices. Thus, safety education and management are needed for these workers.     

Respiratory symptoms and chronic obstructive pulmonary disease among cement factory workers

OBJECTIVES: This study assessed chronic respiratory symptoms and chronic obstructive pulmonary disease (COPD) among workers exposed to cement dust at a Tanzanian cement factory. METHODS: A total of 120 exposed workers and 107 controls participated in this cross-sectional investigation. Information on demographics, occupational history, chronic respiratory symptoms, smoking habits, and use of respiratory protection equipment was collected by questionnaire. Ventilatory function testing and measurement of personal total dust exposure were also carried out. COPD was diagnosed for workers with chronic bronchitis who also had spirometric airflow obstruction. Chronic respiratory symptoms and COPD were correlated with cumulative total dust exposure and adjusted for age, pack-years, and education. RESULTS: The exposed workers had more chronic cough [odds ratio (OR) 4.5, 95% confidence interval (95% CI) 1.9-10.4], chronic sputum production (OR 10.8, 95% CI 4.4-26.4.), dyspnea (OR 5.3, 95% CI 1.9-15.2), work-related shortness of breath (OR 4.8, 95% CI 1.6-14.2), and chronic bronchitis (OR 5.5, 95% CI 2.0-15.3) than the controls. Chronic cough, chronic sputum production, dyspnea, work-related shortness of breath, and chronic bronchitis were significantly related to cumulative dust exposure of 20.0-99.9 and > or = 100.0 versus <20.0 mg/m3-years. The prevalence of COPD was higher for the exposed group (18.8%) than for the controls (4.8%). The odds ratio for COPD was significantly increased for cumulative dust exposure, > or = 100.0 versus <20.0 mg/m3-years (OR 11.2, 95% CI 2.2-56.0). CONCLUSIONS: Cement workers seem to be at high risk of developing chronic respiratory symptoms and COPD, probably caused by cumulative total dust exposure independent of smoking habits.     

Monitoring of respiratory function in hemp-processing workers]

In a follow-up study the prevalence of chronic respiratory symptoms and changes in ventilatory capacity were followed over a period of three years in 38 female and 28 male hemp workers in a textile industry. The prevalence of all respiratory symptoms was found to be increased. Significant acute reductions of ventilatory capacity were recorded during the work shift. The measured ventilatory capacity values were significantly decreased in comparison to predicted normal values. The mean annual decline of FVC (range: 0.014-0.065 L), FEV1 (range: 0.041-0.068 L), FEF50 (range: 0.020-0.220 L/s) and FEF25 (range: 0.030-0.140 L/s) was considerably greater than in healthy non-exposed subjects. The mean annual decline of all tests was considerably larger in workers with the symptoms of byssinosis than in those without such symptoms. Our data suggest that long-term exposure to hemp dust may cause the development of chronic respiratory symptoms and impairment of ventilatory capacity.     

Respiratory symptoms and spirometry in experienced coal miners: Effects of both distant and recent coal mine dust exposures

The goal of this study was to determine whether respiratory symptoms were associated with the lower concentrations of respirable coal mine dust that were required by the U.S. Coal Mine Health and Safety Act (CMHSA) of 1969. The subjects were 1,866 male miners who had participated in the National Study of Coal Workers' Pneumoconiosis (NSCWP) and been tested at least twice, initially in either Round 1 (R1) (1969–71) or Round 2 (R2) (1972–75) and then finally in Round 4 (R4) (1985–88). Self-reported information elicited with a standardized questionnaire was used to determine the presence at the final round (i.e., R4) of chronic bronchitis, shortness of breath, and wheeze. Cumulative coal mine dust exposure was characterized for both the pre- and post-CMHSA periods. Controlling for age and other potential confounders, increased risks for the symptoms were associated with higher levels of both measurements of exposure. Moreover, the adverse effects of the lower, post-CMHSA exposures were evident for shortness of breath and wheeze especially among subjects who had little pre-CMHSA coal mining experience. These findings provide additional evidence of the limitations of the current 2.0 mg/m³ coal mine dust standard to prevent respiratory disease. Am. J. Ind. Med. 32:268-274, 1997. © 1997 Wiley-Liss, Inc.     

Development of a job exposure matrix (JEM) for the textile industry in Shanghai, China

We developed a job exposure matrix (JEM) for the Shanghai textile industry constructed along three axes: industry sector, textile process, and hazardous agent. We assessed 35 different categories of dust, chemical, and physical agents for 149 textile processes within nine industry sectors: cotton, cotton/synthetic, cotton/other (nonsynthetic), wool, silk, synthetic, mineral, other mixed (e.g., wool and synthetic), and nonproduction. The JEM was constructed from two components: a priori assessment of the textile process by a team of U.S. industrial hygienists, and the prevalence of exposures reported by Chinese industrial hygienists in specific textile processes within the factory. The JEM was applied to an ongoing case-cohort study of cancer in women textile workers. The JEM assessed only dichotomous exposure (ever/never), and could be coupled with cumulative exposure by years of employment. The most common exposures in cotton mills were cotton dust and solvent exposures. Dyeing processes had the highest frequency of exposures, including solvents, acids, bases and caustics, bleaching agents, dyes, dye chemicals and intermediates, and formaldehyde. Only two processes were identified with formaldehyde exposure, beck dyeing and resin finishing. The most prevalent exposures among the subcohort, occurring in more than 60% of the women, were electromagnetic fields, lubricants, and cotton dust. More than one-third of subcohort subjects were also exposed to synthetic fiber dust, and slightly less than one-third of women were exposed to endotoxin. This JEM could be applicable for epidemiologic research in other textile industries.     

Exposure-response relationships for coal mine dust and obstructive lung disease following enactment of the Federal Coal Mine Health and Safety Act of 1969.

Underground U.S. coal miners were studied cross-sectionally for the association of respirable coal mine dust exposure with pulmonary function and symptoms of airways obstruction. The study group included 1,185 miners participating in Round 4 of the National Study of Coal Workers' Pneumoconiosis who had started mining in or after 1970 when comprehensive exposure regulations first came into effect. Quantitative estimates of cumulative exposure, derived using respirable dust measurements taken by the Mine Safety and Health Administration over the entire study period, were used in linear and logistic regression models on indicators of pulmonary function and chest symptoms while controlling for smoking status, pack-years, and other potential confounders. Statistically significant associations between log cumulative exposure and decrements in FVC, FEV1, and FEV1/FVC were observed. In logistic models, statistically significant associations of cumulative exposure with increasing prevalence of FEV1 and FEV1/FVC less than 80% predicted and symptoms including chronic phlegm, chronic bronchitis, breathlessness, wheeze, and wheeze with shortness of breath were found. It is concluded that exposures to respirable coal mine dust present in U.S. mines since 1970 continue to affect respiratory health in underground miners.     

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

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

Endotoxin exposure and respiratory symptoms in the cotton textile industry

One hundred fourteen male employees of a cotton spinning mill in western Germany participated in a cross-sectional study, the purpose of which was to clarify the dose effect of endotoxin exposure on respiratory symptoms. Airborne endotoxin exposures were classified as low (< or = 100 endotoxin units [EU]/m3), medium (> 100-450 EU/m3), or high (> 450 EU/m3), on the basis of endotoxin activity in the Limulus amoebocyte lysate assay. Age- and smoking-adjusted odds ratios (ORs) and confidence intervals (CIs) were estimated. The dose-response relationship between current endotoxin exposure and prevalence of wheezing (medium: OR = 2.15, 95% CI = 0.48-9.62; high: OR = 5.49, 95% CI = 1.17- 25.81) and cough (medium: OR = 2.11; 95% CI = 0.59-7.56; high: OR = 3.93; 95% CI = 1.02-15.12) was significant (test for linear trend: p values = 0.020 and 0.040, respectively). The association between exposure and wheezing was stronger among atopic workers. The higher prevalence of chest tightness and shortness of breath among workers with medium and high current endotoxin exposure did not reach statistical significance. The results suggested that there was a dose-dependent increase in bronchial symptoms, with significant effects occurring at exposures that exceeded 450 EU/m3.     

Respiratory disease in a textile factory in Nicaragua

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

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.     

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.

     

Respiratory symptoms and lung function effects of domestic exposure to tobacco smoke and cooking by gas in non-smoking women in Singapore.

STUDY OBJECTIVES--To investigate the effects of passive exposure to tobacco smoke and gas cooking at home on respiratory symptoms and lung function of non-smoking women. SETTING--Evidence on the effects of passive smoking and exposure to nitrogen dioxide from gas cooking on the respiratory health of adults is limited and variable. Over 97% of women in Singapore do not smoke, and a principal source of indoor air pollution for housewives is passive smoking and gas cooking. DESIGN--This was a cross sectional (prevalence) study of a population based sample of 2868 adults aged 20 to 74 years in Singapore. A structured questionnaire administered by trained interviewers was used to collect data on passive smoking, gas cooking, respiratory symptoms, and other relevant variables. Passive smoking was defined as exposure to cigarette smoke from one or more members of the household who had ever smoked. Gas cooking was defined in terms of the weekly frequency of gas cooking, as well as the frequency with which the respondent's kitchen was filled with heavy cooking fumes (rarely, occasionally, often). Forced expiratory volume in one second (FEV1) was measured by using a portable Micro-spirometer. Multivariate analyses were used to estimate relative odds of association for respiratory symptoms and FEV1 effect, with adjustment for potential confounding variables. PARTICIPANTS--Of a total of 1438 women in the sample, 1282 women who had never smoked provided questionnaire data and 1008 women provided acceptable readings of FEV1 for analysis. MAIN RESULTS--Passive smoking was significantly associated with greater relative odds of usual or chronic cough and phlegm, wheezing, and breathlessness on exertion, as well as lower FEV1. Greater relative odds of respiratory symptoms were also associated with the weekly frequency of gas cooking, although these results were statistically insignificant. Chronic cough and phlegm and breathlessness on exertion, however, were significantly associated with the frequency with which the kitchen was filled with heavy cooking fumes. A lower FEV1 was found in women who cooked frequently (more than thrice a week). CONCLUSION--Domestic exposure to cigarette smoke and gas cooking is associated with increased risks of respiratory symptoms and impairment of lung function in non-smoking women in Singapore.