Four-year follow-up of effects of toluene diisocyanate exposure on the respiratory system in polyurethane foam manufacturing workers

A 4-year cohort study was designed to assess the exposure-effect relationship of working in polyurethane foam (PF) manufacturing factories with exposure to toluene diisocyanate (TDI) and its effects on the respiratory system. This paper describes the results of the first cross-sectional observations. The study population included 90 male workers who had been working in PF factories for 0.5-25 years (mean 13.3 years) (PF workers) and 44 reference workers in the same factories. The mean exposure concentration of TDI calculated from 129 personal samples was 3.2 ppb. Peak exposure excursions above 20 ppb occurred in 16 of 129 samples. Pulmonary function and its change during the working day as assessed by examining the forced expiratory flow-volume curve, respiratory impedance, and airway resistance and specific airway conductance were not different in the PF workers from those in the reference workers. Chest X-radiographs did not show any noteworthy radiological changes. Prevalences of "phlegm in winter," "nasal stuffiness or discharge in winter," and "irritation of eye and throat mucous membranes" were significantly higher in the PF workers. The findings indicate that TDI exposure at levels around 3 ppb may not adversely affect the pulmonary function over many years of exposure of those who are not hypersensitive to TDI. The causal chemicals inducing some respiratory and irritative symptoms could not be specifically identified since the PF workers were exposed not only to TDI but also to other irritative agents in the PF manufacturing processes.     

Obstructive pulmonary function defects among Taiwanese firebrick workers in a 2-year follow-up study.

The purpose of the study was to follow up an earlier observation of pulmonary function among workers employed in firebrick-manufacturing factories. A 2-year follow-up study of pulmonary function among 442 workers in 30 firebrick-manufacturing factories was designed. Excluding 79 workers with a history of other occupational dust exposure, changes in pulmonary function of 291 firebrick workers were compared with pulmonary function in 72 control subjects over a period of 2 years. Baseline pulmonary function values (i.e., forced expiratory volume in 1 second [FEV1]/forced vital capacity [FVC] and forced expiratory flow after 50% of vital capacity has been expelled [FEF50%] in smoking firebrick workers, and FEV1/FVC and FEF75% in nonsmoking firebrick workers) were significantly lower than those in the comparison group. The statistical method for repeated measurements was used for comparison of the difference between follow-up and baseline lung function. There was no significant difference in FVC and FEV1 changes between firebrick workers and those in the comparison group during the 2-year follow-up period. The decreases in FEV1/FVC, peak expiratory flow rate, maximal midexpiratory flow, and FEF50% in the firebrick workers were significantly greater than in the comparison group, after adjustment for smoking status. The FEV1, maximal midexpiratory flow, FEF50%, and FEF75% also showed a dose-response relationship with job titles. The decrement of pulmonary function in the 2-year follow-up period was the worst in burning work, followed by crushing and molding. The results show that workers in firebrick-manufacturing factories with exposure to silica-containing dusts may contract obstructive pulmonary function defects.     

Two-year observation of pulmonary function in workers exposed to low concentrations of toluene diisocyanate

Summary Pulmonary effects were investigated in 106 toluene diisocyanate (TDI)-exposed workers and 39 referents in 1980 and in 64 exposed workers and 21 referents on the 2-year follow-up study in 1982. Means of individual, time-weighted average (TWA) exposure concentrations measured by personal monitors were approximately 0.001 ppm in each year. Short-term exposure at 0.02 ppm or over was observed in 9.3% of the collected samples in 1980 and 1.9% in 1982. Pulmonary function was assessed by measurements of maximum expiratory flow-volume curve and respiratory impedance. No differences were observed in the means of the pulmonary functions and their individual daily changes between the TDI workers and the referents. Significant intra-individual, two-year decreases were observed in some pulmonary function parameters in both groups, but when the effect of aging was adjusted, the decreases disappeared. Prevalences of respiratory symptoms in the TDI workers were not significantly higher than those in the referents, except for irritating complaints of the eyes and throat probably due to peak exposure to TDI and/or co-existing irritants. Eight of the TDI workers had episodes of acute asthmatic reactions shortly after having begun their TDI jobs and most parameters in their maximum expiratory flow were significantly less than the predicted values, though exposure concentrations when the episodes occurred could not be defined. From these results, it was suggested that TDI exposure at the levels of 0.001 ppm may not induce adverse pulmonary effects when the workers are not hypersusceptive to TDI.     

某煤矿掘砌工人肺通气功能分析

[目的]了解煤矿掘砌工人肺通气功能损伤情况,探讨接尘工龄对肺功能的影响。[方法]。选取某煤矿纯掘砌工（纯掘砌作业工人）221名作为接尘组,选取该矿83名非接尘工人作为对照。行统一的体检和肺功能测定。测定结果均采用相对值,运用卡方检验、协方差分析进行统计学处理。[结果]接尘组非吸烟工人肺通气功能异常率与对照组差异不具有统计学意义（P〉0．05）,而接尘组吸烟工人肺通气功能异常率高于对照组（P〈0．05）。Mantel—Haenszel妒分析显示接尘组肺通气功能异常率高与对照组（P〈0．05）。以吸烟作为协变量,协方差分析结果显示,接尘组的用力肺活量、第一秒用力呼出量、呼气高峰流量、用力肺活量最大值、第一秒用力呼出量最大值明显低于对照组（尸〈0．05）。以吸烟为协变量,协方差分析结果显示,接尘组30年一工龄组呼气高峰流量和25％肺活量最大呼气流量明显低于10年～工龄组和20年～工龄组。以吸烟为分层因素,接尘组与对照组以及接尘组不同工龄间慢性阻塞性肺疾患患者分布差异均无统计学意义（P〉0．05）。[结论]掘砌作业工人肺通气功能明显低于对照组并随接尘工龄延长而降低。肺通气功能检测可以作为监测接尘作业工人肺部损失的指标。     

Spirometric function in non-smoking workers exposed to aluminum

BACKGROUND: Exposure to aluminum (Al) causes the onset of respiratory disorders. This study is aimed at providing further information on how occupational exposure to Al affects the respiratory apparatus in healthy non-smokers, with particular attention to respiratory function. METHODS: A group of 50 male shipyard workers who were exposed to Al underwent medical examination, standard chest X-rays and spirometry in accordance with the C.E.C.A. protocol. The data were compared with those of a homogeneous group of controls, all with blood aluminum (AlB) levels below 7.5 ng/ml. Statistical analysis was performed on the following spirometric parameters: vital capacity (VC), forced vital capacity (FVC), maximum forced expiratory volume in 1 s (FEV1), and mean forced expiratory flow during mid-half of FVC (FEF(25-75%)). Environmental Al levels were also measured at the various workstations. RESULTS: Fifty male workers with an average age 31.82 +/- 5.05 years, occupational exposure of 11.81 +/- 3.71 years, presented with average AlB levels of 32.64 +/- 8.69 ng/ml. Environmental monitoring displayed Al levels higher than TLV TWA for all the workstations studied. None of the sample displayed significant pathological conditions. Statistical comparison of the spirometric parameters showed a decrease in the examined values in exposed workers. This decrease was found to be directly proportional to the AlB level. CONCLUSION: The authors conclude that Al affects respiratory function and that limit values should be reassessed.     

A longitudinal study of respiratory health of toluene diisocyanate production workers

A longitudinal comparison of 305 toluene diisocyanate (TDI) and 581 hydrocarbons workers employed at a Texas chemical manufacturing facility from 1971 through 1997 tested whether workplace exposure to TDI was associated with changes in any of the respiratory measures collected by the company's health surveillance program. Mean TDI exposures measured 96.9 ppb-months, or 2.3 ppb per job. At the end of the study, there were no differences in self-reported symptoms between the groups. Longitudinal analyses of symptoms and pulmonary function showed no correlation with TDI exposure, yielding an average annual decrease in forced expiratory volume at 1 second of 30 mL per year. We concluded that exposure to TDI at workplace concentrations was not associated with respiratory illnesses in this cohort, and consistent with other recent research, it seemed not to accelerate the normal age-related decline in pulmonary function.     

Cement dust exposure and ventilatory function impairment: an exposure-response study

We investigated cumulative total cement dust exposure and ventilatory function impairment at a Portland cement factory in Tanzania. All 126 production workers were exposed. The control group comprised all 88 maintenance workers and 32 randomly chosen office workers. Exposed workers had significantly lower forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEF), FEV1/FVC, FVC%, FEV1% and PEF%, than controls adjusted for age, duration of employment, height, and pack-years. Cumulative total dust exposure was significantly associated with reduced FVC, forced expiratory volume in 1 second, and peak expiratory flow rate adjusted for age, height and pack-years. Cumulative total dust exposure more than 300 mg/m year versus lower than 100 mg/m years was significantly associated with increased risk of developing airflow limitation (odds ratio = 9.9). The current occupational exposure limit for total cement dust (10 mg/m) appears to be too high to prevent respiratory health effects among cement workers.     

Follow-up study on pulmonary function of dust workers: an epidemiological evaluation of discontinued workers of dust operations

An epidemiologic study on 176 dust workers from various facilities was initiated in 1978. Their mean age was 48.3 years and mean duration of employment was 21.6 years. No workers complained of chronic cough and phlegm. Their chest X-rays were found to belong to Category I of the diagnostic criteria for pneumoconiosis in Japan. Pulmonary function test was performed on these workers, however, 54 workers discontinued taking part in the study by the end of 1979, and 49 workers had discontinued by 1981. A total of 73 workers had a five-year follow-up survey of pulmonary function. Forced expiratory volume in one second divided by forced vital capacity (FEV1.0/FVC) and forced expiratory flow rate at 25% of FVC divided by height (V25/H) were mainly compared by smoking habit, work years, type of job, size of company, and the time when they discontinued their jobs. Predicted percentage values of lung function were used for the adjustment of the influence of workers' ages. Decrement of FEV1.0/FVC and V25/H in the five-year follow-up group were larger than the screening level. The mean values of those functional parameters in the early discontinued group were lower than late discontinued and active working groups. The active working group was considered to be a physically healthy workers' population.     

A 17-year epidemiological study on changes in lung function in toluene diisocyanate foam workers

OBJECTIVE: To determine whether longitudinal declines in ventilatory capacity and the occurrence of respiratory symptoms in workers manufacturing polyurethane foam were related to toluene diisocyanate (TDI) exposure. METHODS: A population of workers from 12 UK factories was studied between 1981 and 1986 [8]. A survivor cohort of 251, of whom 217 were in the 1981-1986 study, was examined again in 1997-1998. Modified British Medical Research Council respiratory questionnaires and lung function measurements were completed for each of the 251 subjects at the beginning and end of the 17-year study period. Mean TDI exposures for all jobs in which subjects were employed were assessed and related to their occupational histories. RESULTS: The annual declines in 1-second forced expiratory volume (FEV(1)) and forced vital capacity (FVC) were not related to TDI exposure, and were typical of those measured in other populations not exposed to TDI. Over the study period the cold-foam handling group ( n=26) showed an increase in breathlessness and a significant excess decline in FVC; the exposed group ( n=175) showed an increase in wheezing (mainly smokers), whilst the low-exposure group ( n=50) showed a decrease in chest illness. Smoking and an increase in body weight both caused excess declines in FEV(1). CONCLUSIONS: This study does not provide evidence that there was any TDI-related decline in FEV(1) or in FVC over a 17-year period in workers exposed to TDI at the levels prevailing in the UK factories that manufactured flexible polyurethane foam.     

An epidemiology study of lung function changes of toluene diisocyanate foam workers in the United Kingdom

Objective: To determine whether longitudinal declines in ventilatory capacity and the occurrence of respiratory symptoms in workers manufacturing polyurethane foam were related to toluene diisocyanate (TDI) exposure. Methods : A population of 780 workers in 12 United Kingdom factories was followed for 5 years. Modified United Kingdom Medical Research Council (MRC) respiratory questionnaires and three or more lung function measurements were completed for each subject. Mean TDI exposures for all jobs in which subjects were employed were assessed by personal monitoring (2294 measurements) and related to their occupational histories. Results : The United Kingdom 8-h and 15-min maximum exposure limits for TDI were exceeded in 4.7% and 19.0% of the samples taken, respectively. There was some increase in reported respiratory symptoms amongst exposed workers, but the annual declines of 1-s forced expiratory volume (FEV₁) and forced vital capacity (FVC) were not related to TDI exposure and were typical of those observed in other longitudinal populations. FEV₁ declines were smoking-related. Evidence was found suggesting that a small excess decline in FEV₁ and FVC occurred in the first few years of employment for workers not previously exposed to TDI. Conclusion: This study does not provide evidence that there is a TDI-related decline in FEV₁ and FVC in workers exposed to less than the United Kingdom 8-h occupational exposure limit of 5.8 ppb. Received: 21 February 1997 / Accepted: 10 July 1997     

Long-term effects on the health of men engaged in the manufacture of tolylene di-isocyanate.

A prospective study of workers engaged in the manufacture of tolylene di-isocyanate (TDI) was carried out over nine years. The study was in two parts: (1) assessment of the symptoms and ventilatory function of men working on the plants who did not complain of respiratory symptoms; (2) assessment of the long-term effects in men who were removed from the plants because of respiratory symptoms. Use of the MRC Questionnaire on Respiratory Symptoms in a group of 76 TDI workers showed no significant differences in symptoms compared with 76 control subjects. Annual lung function tests were carried out on 180 asymptomatic men with possible exposure to TDI. The relationship of the forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) to the height, age, and duration of exposure was examined by linear regression analysis. The equations formulated did not differ significantly from those calculated for non-TDI exposed subjects. Thus exposure to very small concentrations of TDI does not necessarily cause symptoms or a drop in ventilatory capacity. Forty-six TDI workers who had developed symptoms reported more long-term symptoms than a comparable number of controls. The difference was significant at the 1% level. Ventilation test records of 61 TDI workers who had developed symptoms were available since it was possible to use the records of men who had left the company. The lung function of this group was matched against predicted figures obtained from a control group of 608 subjects living in the same area as the exposed group but not exposed to TDI. It was found that the FEV1 of the affected men was on average 267 ml lower than predicted, and the FVC 269 ml lower. These findings are confirmed by examination of the indivdual records of a futher 20 men.     

Long-term effects on the health of men engaged in the manufacture of tolylene di-isocyanate.

A prospective study of workers engaged in the manufacture of tolylene di-isocyanate (TDI) was carried out over nine years. The study was in two parts: (1) assessment of the symptoms and ventilatory function of men working on the plants who did not complain of respiratory symptoms; (2) assessment of the long-term effects in men who were removed from the plants because of respiratory symptoms. Use of the MRC Questionnaire on Respiratory Symptoms in a group of 76 TDI workers showed no significant differences in symptoms compared with 76 control subjects. Annual lung function tests were carried out on 180 asymptomatic men with possible exposure to TDI. The relationship of the forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) to the height, age, and duration of exposure was examined by linear regression analysis. The equations formulated did not differ significantly from those calculated for non-TDI exposed subjects. Thus exposure to very small concentrations of TDI does not necessarily cause symptoms or a drop in ventilatory capacity. Forty-six TDI workers who had developed symptoms reported more long-term symptoms than a comparable number of controls. The difference was significant at the 1% level. Ventilation test records of 61 TDI workers who had developed symptoms were available since it was possible to use the records of men who had left the company. The lung function of this group was matched against predicted figures obtained from a control group of 608 subjects living in the same area as the exposed group but not exposed to TDI. It was found that the FEV1 of the affected men was on average 267 ml lower than predicted, and the FVC 269 ml lower. These findings are confirmed by examination of the indivdual records of a futher 20 men.     

Pulmonary function in fur-processing workers: a dose-response relationship

Pulmonary function tests were conducted in 212 male workers exposed to fur dust in a fur-processing factory, and in 148 unexposed male workers. The authors used the cumulative dose of dust exposure (mg-yr) as an exposure index to relate to pulmonary function injury, as measured by pulmonary function tests, in exposed workers. The results showed that fur workers had lower percentages of predicted pulmonary function, as measured by forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1.0), and maximal flow rate of expiration at 50% and 25% of forced vital capacity (V50 and V25, respectively), compared with controls (p < 0.01). As the cumulative dose of fur dust exposure increased, average levels of pulmonary function declined significantly (p < 0.01), and pulmonary function abnormalities (i.e., < 80% of predicted FVC and FEV1.0, or < 70% of predicted V50 and V25) increased significantly (p < 0.05). Multiple-regression results identified fur dust exposure as the leading risk factor associated with the decline in pulmonary function in the exposed group. The results demonstrated a dose-response relationship between fur dust exposure and respiratory system injury, as measured by pulmonary function tests in fur-processing workers. On the basis of this dose-response relationship and the use of lifetables, the authors proposed an exposure limit of 4 mg/m3 for fur dust.     

Occupational asthma,lung function decrement,and toluene diisocyanate (TDI) exposure: a critical review of exposure-response relationships

An extensive amount of clinical/epidemiological literature exists regarding the effects of toluene diisocyanate (TDI) exposure on respiratory health. This review presents an evaluation and synthesis of that literature with an emphasis on assessing exposure-response relationships in the workplace. The key respiratory disorders examined are bronchial asthma and an accelerated decline in lung function. In the early years of the industry, annual incidence rates of TDI-induced occupational asthma (OA) were as high as 5-6 percent. In settings where mean TDI concentrations have been maintained below 5 ppb based on 8-hr personal samples, OA incidence rates have declined to < 1 percent annually. Recent data also suggest that overexposure incidents may play an important role in inducing OA, particularly in work environments engineered to minimize routine ambient air concentrations. Fourteen studies were reviewed that examined lung function decrement. Early studies from the 1960s and 1970s provided evidence of transient or fixed lung function loss (measured as a decline in forced expiratory volume in one second [FEV1]) during periods of ongoing exposure among employees experiencing high rates of work-related symptoms of OA. Such findings would not be unexpected in that modest FEV1 declines have been demonstrated in general population studies of persons with bronchial hyperresponsiveness or persistent non-occupational asthma. More recent workplace studies have provided no consistent evidence of accelerated FEV1 loss among employees exposed up to 5 ppb TDI (8-hr TWA) even with documented routine short-term TDI concentrations exceeding 20 ppb TDI.     

Evaluation of pulmonary function in workers exposed to hexamethylene diisocyanate.

Production of hexamethylene diisocyanate (HDI) biuret and trimer from HDI monomer was started in 1988 at the plant under study. Pulmonary function tests were included as part of the annual evaluation of the workers in that unit. HDI is expected to have toxic properties similar to those of toluene diisocyanate. The latter has caused accelerated declines in pulmonary function in exposed workers. In 1991, an initial longitudinal evaluation of those pulmonary function tests was performed, comparing annual declines in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). The purpose of the study was to evaluate whether or not exposures to HDI at the unit had caused any accelerated decline in FVC or FEV1. No significant differences were seen in that evaluation, but it was decided that the study be continued in a prospective fashion. The study has been continued through 1997. The slope of the annual change in FVC and FEV1 were calculated for a group of workers and a matched control group. The average annual decline in FVC for the exposed group (cases) was 0.026 L, compared with 0.025 L for the control group. For the decline in FEV1, the results were 0.044 L, compared with 0.041 L (P = 0.79). These results are virtually identical and support a conclusion that exposures within this unit to HDI have not caused an accelerated decline in FVC or FEV1. Exposures to HDI were measured during this period. The time-weighted average exposure to HDI during work not requiring respiratory protection in the unit (approximately 2 hours per day) was 0.5 parts per billion. The average daily high peak exposure was 2.9 parts per billion. Exposure to these levels appear to pose no risk of accelerated decline in pulmonary function.     

空气细颗粒物对交通警察肺通气功能及呼吸道症状的影响

目的 研究空气细颗粒物(PM2.5)暴露对交通警察呼吸道症状及肺通气功能的影响.方法 使用个体采样器测定上海市区107名男性外勤交通警察(高暴露组)及101名居民(一般暴露组)PM2.5的暴露情况,问卷调查获得交通警察和居民的基本情况、呼吸道症状,测定用力呼气肺活量(FVC)、第1秒用力呼气容积(FEV1.0)、FEV1.0/FVC%和最大呼出流速(PEF).比较交通警察和居民PM2.5暴露及呼吸道症状、肺通气功能的差异,对交通警察按工龄分组,研究工龄对肺通气功能的影响,并对肺通气功能降低与颗粒物暴露水平的进行相关分析.结果 交通警察和居民细颗粒物24 h个体平均暴露浓度为分别(115.4±46.17)和(74.94±40.09)μg/m3,高暴露组PM2.5暴露水平明显高于一般暴露组,差异有统计学意义(P＜0.01).高暴露组咳嗽、咳痰、咽部不适及气喘、气短和鼻部不适的发生率明显高于一般暴露组,差异有统计学意义(P＜0.05,P＜0.01),高暴露组肺通气功能指标FVC实测/FVC预计%和FEV 1.0实测/FEV1.0预计%的异常率分别为25.23%和12.15%,一般暴露组FVC实测/FVC预计%和FEV1.0实测/FEV1.0预计%的异常率分别为11.88%和2.97%,两组比较,差异有统计学意义(P＜0.05,P＜0.01),且高暴露组FVC实测/FVC预计%、FEV1.0实测/FEV1.0预计%异常率随工龄延长呈现升高的趋势.结论 长期暴露于较高水平的PM2.5会危害人体呼吸系统健康,导致呼吸道症状增多,降低肺通气功能.     

Formaldehyde exposure,acute pulmonary response,and exposure control options in a gross anatomy laboratory

Formaldehyde exposure, acute pulmonary response, and exposure control options were evaluated in a group of 34 workers in a gross anatomy laboratory. Time-weighted average (TWA) exposure to formaldehyde ranged from 0.07–2.94 parts per million (ppm) during dissecting operations. More than 94% were exposed to formaldehyde in excess of the ceiling value of 0.3 ppm recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The eight-hour TWA exposure of 31.7% of the subjects exceeded the action level of 0.5 ppm set by the Occupational Safety and Health Administration (OSHA). Reported symptoms included irritation of eye (88%), nose (74%), throat (29%), and airways (21%). Forced vital capacity (FVC) and forced expiratory volume in 3 seconds (FEV₃) decreased, and FEV₁/FVC increased during the exposure. The changes of FEV₃ were statistically different from those of the controls. The results strongly support the necessity for designing and testing special local exhaust-ventilated worktables with necessary flexibility for dissecting operations.     

慢性阻塞性肺病患者营养状况与肺通气功能关系的研究

目的探讨慢性阻塞性肺病(chronicobstructivepulmonarydisease,COPD)患者营养状况对肺通气功能的影响。方法对149例COPD患者根据其营养状况分为营养正常组和营养不良组,再进行肺通气功能测定,观察指标包括最大通气量(MVV),用力肺活量(FVC),第一秒用力呼气容积(FEV1),最大呼气流量(PEF),最大呼气中段流量(MMEF)。结果营养不良组与营养正常组比较,MVV、FVC、PEF、FEV1等反映呼吸肌的指标相差非常显著(P<0.001),且两组在COPD病程同一阶段(肺气肿、肺心病)肺通气功能各值比较也显示营养不良组呼吸肌力等指标比正常组降低明显(P<0.05)。结论COPD合并营养不良对与呼吸肌有关的肺通气功能指标有明显影响。     

陶瓷作业工人肺功能测试结果分析

目的了解陶瓷作业工人肺功能损害的情况,为预防尘肺病发生提供依据。方法选择某陶瓷厂200名接尘工人,平均年龄为（32.31±8.25）岁,另选取非接尘工人50名为对照组,平均年龄为（34.88±9.75）岁,采用意大利的spirolabII型的肺功能仪,测试的项目包括肺活量（VC）、用力呼吸肺活量（FVC）、第1s用力呼气量（FEV1）、一秒率（FEV1%）、最大呼气中段流速（FEF25-75）、最大呼气25%、50%、75%肺活量时流量（FEF25%、FEF50%、FEF75%）;应用SPSS13.0统计软件统计分析。结果接尘组的肺功能指标FEV1、FEV1%、FEF25-75、FEF50%、FEF75%明显低于对照组,差异有统计学意义（P〈0.05）;接尘工龄在10年～、15年～、20年～组的工人肺功能指标中VC、FVC、FEF25-75、FEF50%、FEF75%的测试均值明显低于接尘工龄〈5年组,差异有统计学意义（P〈0.05）。结论陶瓷粉尘对作业工人的肺功能有损害作用,且随着接尘工龄的增加肺功能受损害程度增加。     

A longitudinal study of lung function in jute processing workers.

A 5-y follow-up study of pulmonary function was conducted in 1982 and in 1987 for 50 current and retired jute-processing workers who had been employed for more than 10 y in a jute mill in China. Control subjects, who had no history of dust or gas exposure, were selected from a paper-packing plant in the same city. Forced expiratory maneuvers were conducted in the same manner in both 1982 and 1987. The jute workers' pulmonary functions, i.e., forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), and forced expiratory flow (FEF25-75%), were more compromised than were pulmonary functions in the controls for the same 5-y period; however, only the increased incidence of abnormal FEV1.0s in jute workers was statistically significant. Male jute workers had significantly higher annual decrements of FVC, FEV1.0, and FEF25-75% than did control workers. Regression analysis indicated that in 1987, predicted values of FEV1.0 and FEF25-75% for the jute workers were related to years of employment. Our results suggest that long-term exposure to jute dust could produce chronic loss of lung function.