Respiratory symptoms and asthma among workers exposed to paper dust: a cohort study

Occupational exposure to noise and dust in Swedish soft paper mills and mortality from ischemic heart disease and ischemic stroke: a cohort study

OBJECTIVE

To elucidate whether occupational noise exposure increases the mortality from ischemic heart disease (IHD) and stroke, and if exposure to paper dust modified the risks.

METHODS

We studied 6686 workers from soft paper mills, with occupational noise exposure, < 85 dBA, 85-90 dBA and > 90 dBA, and high (> 5 mg/m3) exposure to paper dust. Person-years 1960-2019 were stratified according to gender, age, and calendar-year. Expected numbers of deaths were calculated using the Swedish population as the reference and standardized mortality ratios (SMR) with 95% confidence intervals (95% CI) were assessed.

RESULTS

SMR for IHD was 1.12 (95% CI 0.88-1.41) for noise < 85 dBA, 1.18 (95% CI 0.90-1.55) for 85-90 dBA, and 1.27 (95% CI 1.10-1.47) among workers exposed > 90 dBA. Joint exposure to high noise exposure and high exposure to paper dust resulted in slightly higher IHD mortality (SMR 1.39, 95% CI 1.15-1.67). SMR for ischemic stroke was 0.90 (95% CI 0.37-2.15) for noise < 85 dBA, 1.08 (95% CI 0.45-2.59) for 85-90 dBA, and 1.48 (95% CI 0.99-2.00) among workers exposed > 90 dBA. High noise exposure and high exposure to paper dust resulted in higher ischemic stroke mortality (SMR 1.83, 95% CI 1.12-2.98).

CONCLUSION

Noise levels > 90 dBA was associated with increased IHD mortality. Combined exposures of noise and paper dust may further increase the risks. Our results do not provide support for a causal relationship for ischemic stroke. Residual confounding from smoking has to be considered. Workers need to be protected from occupational noise levels exceeding 90 dBA.

Cancer incidence among workers in soft paper mills: A cohort study

OBJECTIVES

To elucidate whether occupational exposure to soft paper dust increases the incidence of cancer.

METHODS

We studied 7988 workers in Swedish soft paper mills from 1960 to 2008, of whom 3233 (2 187 men and 1046 women) had more than 10 years of employment. They were divided into high exposure (>5 mg/m3 for >1 year) or lower exposure to soft paper dust based on a validated job-exposure matrix. They were followed from 1960 to 2019, and person-years at risk were stratified according to gender, age, and calendar-year. The expected numbers of incident tumors were calculated using the Swedish population as the reference, and standardized incidence ratios (SIR) with 95% confidence intervals (95% CI) were assessed.

RESULTS

Among high-exposure workers with more than 10 years of employment, there was an increased incidence of colon cancer (SIR 1.66, 95% CI 1.20-2.31), small intestine cancer (SIR 3.27, 95% CI 1.36-7.86), and thyroid gland cancer (SIR 2.68, 95% CI 1.11-6.43), as well as lung cancer (SIR 1.56, 95% CI 1.12-2.19). Among the lower-exposed workers there was an increased incidence of connective tissue tumors (sarcomas) (SIR 2.26, 95% CI 1.13-4.51) and pleural mesothelioma (SIR 3.29, 95% CI 1.37-7.91).

CONCLUSION

Workers in soft paper mills with high exposure to soft paper dust have an increased incidence of large and small intestine tumors. Whether the increased risk is caused by paper dust exposure or some unknown associated factors is unclear. The increased incidence of pleural mesothelioma is probably linked to asbestos exposure. The reason for increased incidence of sarcomas is unknown.

Irritant-Induced Chronic Cough Triggers: A Scoping Review and Clinical Checklist

Purpose The primary aim of this review was to identify environmental irritants known to trigger chronic cough through the life span and develop a comprehensive clinically useful irritant checklist. Method A scoping review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Reviews, checklist, and explanation. English-language, full-text resources were identified through Medline, PsycINFO, SPORTDiscus, Web of Science, and ProQuest Dissertations and Theses Global. Results A total of 1,072 sources were retrieved; of these, 109 were duplicates. Titles of abstracts of 963 articles were screened, with 295 selected for full-text review. Using the exclusion and inclusion criteria listed, 236 articles were considered eligible and 214 different triggers were identified. Triggers were identified from North America, Europe, Africa, Asia, and Australia. Occupational exposures were also delineated. Conclusions A clinically useful checklist of both frequently encountered triggers and idiosyncratic or rare triggers was developed. The clinical checklist provides a unique contribution to streamline and standardize clinical assessment of irritant-induced chronic cough. The international scope of this review extends the usefulness of the clinical checklist to clinicians on most continents.

Occupational exposure to soft paper dust and mortality

OBJECTIVES

Occupational exposure to soft paper dust is associated with impaired lung function. Whether there is an increased risk for asthma or chronic obstructive pulmonary disease (COPD) is unclear.

METHODS

We studied 7870 workers from three Swedish soft paper mills, and defined high-exposed workers, as having been exposed to soft paper dust exceeding 5 mg/m³ for at least 5 years. The remaining workers were classified as 'low exposed'. Person-years at risk were calculated and stratified according to gender, age and calendar-year. The follow-up time was from 1960 to 2013. The expected numbers of deaths were calculated using the Swedish population as reference and standardised mortality ratios (SMRs) with 95% CIs were assessed.

RESULTS

There was an increased mortality due to obstructive lung disease (asthma and COPD), among high-exposed workers, SMR 1.89, 95% CI 1.20 to 2.83, based on 23 observed cases. High-exposed workers had an increased mortality from asthma, SMR 4.13, 95% CI 1.78 to 8.14, based on eight observed cases. The increased asthma mortality was also observed among high-exposed men, SMR 4.38, 95% CI 1.42 to 10.2, based on five observed cases. The asthma mortality among low-exposed workers, both men and women, was not increased. The COPD mortality was not clearly increased among high-exposed workers (SMR 1.52, 95% CI 0.85 to 2.50).

CONCLUSION

High occupational exposure to soft paper dust increases the mortality due to asthma, and the results suggest that soft paper dust levels in workplaces should be below 5 mg/m³.

A semi-quantitative job exposure matrix for dust exposures in Swedish soft tissue paper mills

BACKGROUND

Total paper dust exposure has been associated with respiratory problems among workers in the soft tissue paper industry. However, a comprehensive job exposure matrix (JEM) has not been developed for application to this industry. Our study was intended to address this need and to support further studies of mortality and morbidity in a cohort of Swedish workers from this industry.

METHODS

We evaluated four participating soft tissue paper mills in Sweden. We combined information on process and equipment status from the mills with knowledge of the mills obtained through research efforts and paper dust measurements made at all four mills to develop a semi-quantitative JEM with seven dust exposure levels. The JEM was targeted at workers enrolled into a soft tissue paper mill cohort and working any time between 1960 and 2009.

RESULTS

The JEM includes a total of 14 421 cells, with each cell corresponding to the exposure for a job title, department, or work location for a one-year period. Exposure levels in the JEM were estimated to decline at three of the four mills from 1971 to 2009, but overexposures (ie, exceedances of the relevant occupational exposure limits) remained common at the end of the period.

CONCLUSIONS

The JEM results highlight the need for ongoing exposure control efforts in the soft tissue paper industry, and will inform ongoing epidemiological studies of the health effects of exposure to paper dust in Sweden. It is freely available for use by other researchers.

Lung function and paper dust exposure among workers in a soft tissue paper mill

Purpose

To study respiratory effects of exposure to soft paper dust exposure, a relationship that is rarely studied.

Methods

Soft tissue paper mill workers at a Swedish paper mill were investigated using a questionnaire and lung function and atopy screening. Spirometry without bronchodilation was performed with a dry wedge spirometer, and forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were obtained and expressed as percent predicted. Exposure to soft paper dust was assessed from historical stationary and personal measurements of total dust, in addition to historical information about the work, department, and production. The impact of high exposure to soft paper dust (> 5 mg/m³) vs. lower exposure ≤ 5 mg/m³, as well as cumulative exposure, was analyzed using multiple linear regression models. Multivariate models were adjusted for smoking, atopy, gender, and body mass index.

Results

One hundred ninety-eight current workers (124 male and 74 female) were included. There were significant associations between both cumulative exposure and years of high exposure to soft paper dust and impaired lung function. Each year of high exposure to soft paper dust was associated with a 0.87% decrease in FEV₁ [95% confidence interval (CI) − 1.39 to − 0.35] and decreased FVC (− 0.54%, 95% CI − 1.00 to − 0.08) compared to the lower exposed workers.

Conclusions

The present study shows that occupational exposure to soft paper dust (years exceeding 5 mg/m³ total dust) is associated with lung function impairment and increased prevalence of obstructive lung function impairment.

Development of a Job Exposure Matrix for Noise in the Swedish Soft Tissue Paper Industry

Objectives

Noise exposure is a common occupational hazard, but has not been sufficiently characterized in paper mills. We developed a job-exposure matrix (JEM) for noise exposure for use in estimating exposures among Swedish soft tissue paper mill workers.

Methods

We used a combination of area and personal dosimetry noise exposure measurements made at four soft tissue paper mills by industry and research staff between 1977 and 2013 to estimate noise exposures by department, location, and job title. We then utilized these estimates, in conjunction with information on process and facility changes and use of hearing protection collected via focus groups, to create a seven-category, semi-quantitative JEM for all departments, locations, and job titles spanning the years 1940–2010.

Results

The results of the 1157 area and personal dosimetry noise measurements indicated that noise levels have generally declined in Swedish paper mills over time, though these changes have been neither uniform nor monotonic within or across the four mills. Focus group results indicated that use of hearing protection has generally increased over time. The noise JEM totals 1917 cells, with each cell representing a unique combination of operation, job title, and single year. We estimated that ~50% of workers at the four mills assessed were exposed at or above the Swedish 8-h average noise exposure limit of an 85 dBA at the conclusion of the study period in 2010.

Conclusions

Our results highlight the continuing need for hearing loss prevention and noise control efforts at these and similar mills, and the completed JEM now represents a tool for use in epidemiological studies of noise-related health outcomes.

Gender differences in murine pulmonary responses elicited by cellulose nanocrystals

Background

Cellulose-based materials have been used for centuries to manufacture different goods derived from forestry and agricultural sources. In the growing field of nanocellulose applications, its uniquely engineered properties are instrumental for inventive products coming to competitive markets. Due to their high aspect ratio and stiffness, it is speculated that cellulose nanocrystals (CNC) may cause similar pulmonary toxicity as carbon nanotubes and asbestos, thus posing a potential negative impact on public health and the environment.

Methods

The present study was undertaken to investigate the pulmonary outcomes induced by repeated exposure to respirable CNC. C57BL/6 female and male mice were exposed by pharyngeal aspiration to CNC (40 μg/mouse) 2 times a week for 3 weeks. Several biochemical endpoints and pathophysiological outcomes along with gene expression changes were evaluated and compared in the lungs of male and female mice.

Results

Exposure to respirable CNC caused pulmonary inflammation and damage, induced oxidative stress, elevated TGF-β and collagen levels in lung, and impaired pulmonary functions. Notably, these effects were markedly more pronounced in females compared to male mice. Moreover, sex differences in responses to pulmonary exposure to CNC were also detected at the level of global mRNA expression as well as in inflammatory cytokine/chemokine activity.

Conclusions

Overall, our results indicate that there are considerable differences in responses to respirable CNC based on gender with a higher pulmonary toxicity observed in female mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12989-016-0140-x) contains supplementary material, which is available to authorized users.

Respiratory health effects and exposure to superabsorbent polymer and paper dust - an epidemiological study

Background

The primary aim of the present study was to investigate if exposure to dust from absorbent hygiene products containing superabsorbent polymer is related to symptoms from the airways and from the eyes. The secondary aim was to estimate the current exposure to superabsorbent polymer among production and maintenance workers in a plant producing hygiene products.

Methods

The cohort comprised 1043 workers of whom 689 were exposed to super absorbent polymer and 804 were exposed to paper dust (overlapping groups). There was 186 workers not exposed to either superabsorbent polymer or to paper dust They were investigated with a comprehensive questionnaire about exposure, asthma, rhinitis and symptoms from eyes and airways. The results were analyzed with logistic regression models adjusting for sex, age, atopy and smoking habits. An aerosol sampler equipped with a polytetrafluoroethylene filter with 1 μm pore size was used for personal samplings in order to measure inhalable dust and superabsorbent polymer.

Results

The prevalence of nasal crusts (OR 1.4, 95% CI 1.01-2.0) and nose-bleeding (OR 1.7, 95% CI 1.2-2.4) was increased among the paper dust exposed workers (adjusted for superabsorbent polymer exposure). There were no significant effects associated with exposure to superabsorbent polymer (adjusted for paper dust exposure). The average exposure to inhalable levels of total dust (paper dust) varied between 0.40 and 1.37 mg/m³. For superabsorbent polymer dust the average exposure varied between 0.02 and 0.81 mg/m³.

Conclusions

In conclusion, our study shows that workers manufacturing diapers in the hygiene industry have an increased prevalence of symptoms from the nose, especially nose-bleeding. There was no relation between exposure to superabsorbent polymer and symptoms from eyes, nose or respiratory tract, but exposure to paper dust was associated with nose-bleeding and nasal crusts. This group of workers had also a considerable exposure to superabsorbent polymer dust.

Office work exposures and adult-onset asthma

BACKGROUND

Office exposures have been linked to symptoms of sick building syndrome, but their relation to the development of asthma has not been studied previously. These exposures have increasing importance because an increasing proportion of the workforce is working in office environments.

OBJECTIVES

The aim of this study was to assess the relations of exposure to carbonless copy paper (CCP), paper dust, and fumes from photocopiers and printers to adult-onset asthma.

METHODS

We conducted a population-based incident case-control study of adults 21-63 years of age living in the Pirkanmaa District in South Finland. All new clinically diagnosed cases (n = 521) of asthma were recruited during a 3-year study period. A random sample of the source population formed the controls (n = 1,016). This part focused on 133 cases and 316 controls who were office workers according to their current occupation classified by the 1988 International Standard Classification of Occupations. All participants answered a questionnaire on health, smoking, occupation, and exposures at work and home. Subjects with previous asthma were excluded.

RESULTS

Exposures to paper dust [adjusted odds ratio (OR) = 1.97; 95% confidence interval (CI), 1.25-3.10] and CCP (OR = 1.66; 95% CI, 1.03-2.66) were related to significantly increased risk of adult-onset asthma. An exposure-response relation was observed between exposure to paper dust and risk of asthma.

CONCLUSIONS

This study provides new evidence that exposures to paper dust and CCP in office work are related to increased risk of adult-onset asthma. Reduction of these exposures could prevent asthma in office workers. Clinicians seeing asthma patients should be aware of this link to office exposures.

Rayon flock: a new cause of respiratory morbidity in a card processing plant

BACKGROUND

Following employee respiratory concerns, we investigated the health effects of rayon flock exposure at a card manufacturing plant.

METHODS

We conducted a cross-sectional survey including environmental evaluation, standardized questionnaires, spirometry, carbon monoxide diffusing capacity testing, and methacholine challenge testing.

RESULTS

From a total of 239 participants, 146 (61%) reported working at least 1 hr per week in areas where flock-coated cards are processed (flock workers) and 47 (20%) reported cleaning equipment with compressed air. These workers had generally higher prevalences of respiratory symptoms. Flock workers and employees with longer tenure at areas where flock-coated cards are processed were more likely to have restrictive impairment of lung function. Although dust and fiber samples were largely below the detection limits, peak exposures to airborne particulate occurred during cleaning with compressed air.

CONCLUSIONS

Working with rayon flock and cleaning with compressed air were associated with health effects in workers at this plant.

Chronic cough due to occupational factors

Within the large variety of subtypes of chronic cough, either defined by their clinical or pathogenetic causes, occupational chronic cough may be regarded as one of the most preventable forms of the disease. Next to obstructive airway diseases such as asthma or chronic obstructive pulmonary disease, which are sometimes concomitant with chronic cough, this chronic airway disease gains importance in the field of occupational medicine since classic fiber-related occupational airway diseases will decrease in the future.

Apart from acute accidents and incidental exposures which may lead to an acute form of cough, there are numerous sources for the development of chronic cough within the workplace. Over the last years, a large number of studies has focused on occupational causes of respiratory diseases and it has emerged that chronic cough is one of the most prevalent work-related airway diseases. Best-known examples of occupations related to the development of cough are coal miners, hard-rock miners, tunnel workers, or concrete manufacturing workers.

As chronic cough is often based on a variety of non-occupational factors such as tobacco smoke, a distinct separation into either occupational or personally -evoked can be difficult. However, revealing the occupational contribution to chronic cough and to the symptom cough in general, which is the commonest cause for the consultation of a physician, can significantly lead to a reduction of the socioeconomic burden of the disease.

The incidence of respiratory symptoms and diseases among pulp mill workers with peak exposures to ozone and other irritant gases

OBJECTIVES

Pulp mills in Sweden started to use ozone as a bleaching agent in the early 1990s. The goal of this study was to investigate whether the incidence of selected respiratory outcomes was associated with peak exposures to ozone or other irritant gases (ie, chlorine dioxide [ClO2] or sulfur dioxide [SO2]) used in these mills.

METHODS

Bleachery workers (n = 245) from three pulp mills where ozone was used participated in surveys in the mid- to late-1990s. Comparison workers (n = 80) were from two adjacent paper mills. The person-time at risk was calculated for each participant, covering the period of employment when ozone was used. Data were collected by questionnaire, and a peak exposure was defined as a self-reported exposure to an irritant gas resulting in acute respiratory symptoms. The outcomes analyzed were self-reports of physician-diagnosed asthma, attacks of wheeze, and chronic bronchitis (ie, chronic cough with phlegm). Participants also reported when the peak exposures and outcomes occurred.

RESULTS

Based on proportional hazards regression (controlling for gender, age, cigarette smoking, atopy, and peak irritant exposures that occurred before follow-up), workers who reported both ozone and ClO2/SO2 peak exposures had elevated hazard ratios (HRs) for all three outcomes. Those who reported only ozone peak exposures had elevated HRs of 6.5 (95% confidence interval [CI], 1.2 to 36.3) for asthma and 3.3 (95% CI, 1.1 to 10.2) for attacks of wheeze but no increase in risk for chronic bronchitis. Workers with only ClO2/SO2 peak exposures had elevated HRs for attacks of wheeze (HR, 7.5; 95% CI, 1.9 to 29.3) and chronic bronchitis (HR, 22.9; 95% CI, 4.5 to 118.2) but not for asthma.

CONCLUSIONS

These findings suggest the need for additional efforts to prevent peak exposures in pulp-bleaching operations.

Large particles are responsible for elevated bacterial marker levels in school air upon occupation

Muramic acid (Mur) is found in bacterial peptidoglycan (PG) whereas 3-hydroxy fatty acids (3-OH FAs) are found in Gram-negative bacterial lipopolysaccharide (LPS). Thus Mur and 3-OH FAs serve as markers to assess bacterial levels in indoor air. An initial survey, in a school, demonstrated that the levels of dust, PG and LPS (pmol m(-3)) were each much higher in occupied rooms than in the same rooms when unoccupied. In each instance, the Mur content of dust was increased and the hydroxy fatty acid distribution changed similarly suggesting an alteration in the bacterial population. Here, findings are compared with results from two additional schools. Follow-up aerosol monitoring by particle size was also performed for the first time for all 3 schools. The particle size distribution was shown to be quite different in occupied versus unoccupied schoolrooms. Within individual classrooms, concentrations of airborne particles [greater-than-or-equal]0.8 [micro sign]m in diameter, and CO(2) were correlated. This suggests that the increased levels of larger particles are responsible for elevation of bacterial markers during occupation. Release of culturable and non-culturable bacteria or bacterial aggregates from children (e.g. from flaking skin) might explain this phenomenon.

Occupational exposure to chemical agents in the paper industry

As part of an International Agency for Research on Cancer (IARC) international epidemiological study of workers in the pulp and paper industry, previously unpublished exposure measurements were assembled in a database. This article summarizes the results of 3,873 measurements carried out in the production departments of paper and paperboard mills and recycling plants in 12 countries. In the paper and paperboard mills, most of the agents were measured in the pulping and refining departments and in on-machine coating and winding of paper/paperboard. Exposures to asbestos, carbon monoxide, formaldehyde, fungal spores, bacteria, nitrogen dioxide, minerals dusts, paper dust, sulphuric acid and different solvents sometimes exceeded exposure limit values. In the re-pulping and de-inking departments of recycling plants high exposures to formaldehyde, fungal spores, bacteria and paper dust were observed. High exposures to asbestos, bioaerosols, carbon monoxide and paper dust were found in many departments; ammonia, formaldehyde, mineral and paper dust and solvents were found in coating machines; and diphenyl and polychlorobiphenyls (PCBs) were found in some special circumstances. Measurements in the newsprint and uncoated paper machine departments revealed only a few elevated exposures. In nearly all departments, measurements of epichlorohydrin, PCBs, sulphur dioxide, hydrogen sulphide and mercaptans tended to be low, often even below their detection limits. In spite of some uncertainties in the measurement data, the study provides new insights into the level and variation of occupational exposures of production workers in the paper and paperboard industry.

Exhaled nitric oxide: relation to sensitization and respiratory symptoms

BACKGROUND

Conflicting data have been presented as to whether nitric oxide (NO) in exhaled air is merely reflecting atopy rather than airway inflammation.

OBJECTIVE

To investigate the relationship between exhaled NO (eNO) and nasal NO (nNO), respiratory symptoms, and atopy, in the context of a cross-sectional study of the respiratory health of bleachery workers.

METHODS

Two hundred and forty-six non-smoking bleachery and paper-mill workers answered a questionnaire and were examined by measurements of eNO and nNO and spirometry, outside the pollen season. Blood samples were collected and analysed for specific IgE against common aeroallergens (birch, timothy, cat and house dust mite). Atopy was defined as a positive Phadiatop trade mark test.

RESULTS

The atopic and the non-atopic subjects without asthma or rhinitis had similar levels of eNO. Subjects reporting asthma or rhinitis who were also sensitized to perennial allergens had higher levels of eNO, whereas those sensitized to only seasonal allergens had similar eNO levels as non-atopic subjects with asthma or rhinitis. In multiple linear regression models adjusted for nNO, eNO was associated with asthma and sensitization to perennial allergens.

CONCLUSION

The results indicate that only atopic subjects who have recently been exposed to the relevant allergen have elevated levels of eNO. Atopic subjects who are not being exposed to a relevant allergen or have never experienced symptoms of asthma or rhinitis show normal eNO. These data indicate that eNO relates to airway inflammation in atopic subjects.

Respiratory symptoms and diseases among workers in the soft tissue producing industry

AIMS

To correlate the prevalence of respiratory tract symptoms and diseases with dust and fibre exposure in the soft tissue industry in Germany.

METHODS

Ambient monitoring was performed for inhalable, respirable dust and fibres in seven soft tissue producing factories. In 441 workers (72 controls, 90 moderate, 279 high exposure) a standardised questionnaire on respiratory symptoms, diseases, occupational history, and smoking habits was used. Crude differences in the prevalence of respiratory symptoms and diseases were assessed. Logistic regression analysis was used to determine the relation between the respiratory symptoms/diseases and the cumulative dust and fibre exposure, respectively, while adjusting for age, gender, smoking habits, and factory. The effects of exposure intensity and duration were differentiated by categorising dust/fibre concentrations and years of exposure separately and setting up logistic regression models.

RESULTS

The mean concentrations for inhalable, respirable, and fibrous dusts were 10.3 mg/m(3), 0.22 mg/m(3), and 415,000 fibres/m(3). Adjusted odds ratios (OR) with relation to cumulative dust exposure intensity were significantly raised for blocked nose (18.2), mucosal irritation (6.5), dry nose (8.9), cough (3.5), phlegm (7.5), exercise induced dyspnoea (2.6), hoarseness (11.3), and sneezing attacks (7.9) (ORs for highest exposure categories). Cumulative dust or fibre exposure had no significant effects on the prevalence of respiratory diseases. For all symptoms with significantly raised ORs, combined effects of intensity and duration of exposure were found.

CONCLUSIONS

Because of the high prevalence of respiratory symptoms a reduction of dust exposures is recommended. Chronic exposure effects could not be found in this study, however, a healthy worker effect has to be considered.

Respiratory function and immunological status in paper-recycling workers

The respiratory function and immunological status of workers employed in the paper recycling industry were studied. The mean age of the 101 studied workers was 41 years, and the mean duration of their exposure was 17 years. A group of 87 unexposed workers of similar age, duration of employment, and smoking history was studied for the prevalence of chronic respiratory symptoms. Lung function in the paper workers was measured by recording maximum expiratory flow volume (MEFV) curves and recording forced vital capacity (FVC), 1-second forced expiratory volume (FEV1), and maximum expiratory flow rates at 50% and the last 25% of the FVC (FEF50, FEF25). Immunological studies were performed in all 101 paper workers and in 37 control workers (volunteers). These included skin-prick tests with paper-dust extracts and other nonoccupational allergens, as well as the measurement of total serum immunoglobulin E. Significantly higher prevalences of all chronic respiratory symptoms were found in paper compared with control workers (P < 0.01). The highest prevalences were found for chronic cough (36.6%), chronic phlegm (34.7%), chronic bronchitis (33.7%), sinusitis (31.7%), and dyspnea (18.8%). Occupational asthma was diagnosed in four (4.0%) of the paper workers. A logistic regression analysis performed on chronic respiratory symptoms of paper workers indicated significant effects of smoking and exposure, with the smoking effect being the most important. Multivariate analysis of lung-function parameters indicate significant effects of exposure. For paper workers, the measured FEF50 and FEF25 were significantly decreased, compared with predicted values, suggesting obstructive changes located primarily in smaller airways. Among 101 tested paper workers, 16 (15.8%) had positive skin-prick tests to at least one of the paper extracts; none of the control workers reacted to these extracts. Increased serum IgE levels were found in 21% of the paper workers and in 5% of control workers (P < 0.05). Paper workers with positive skin-prick tests to any of the paper and/or other tested extracts had higher prevalences of chronic respiratory symptoms and lower measured lung-function tests compared with predicted than did those with negative skin-prick tests, but the differences were not statistically significant. The measured concentrations of total and respirable dust in this industry were higher than those recommended by Croatian standards. Our study suggests that work in the paper-recycling industry is associated with respiratory impairment and that sensitive workers employed in this industry may be at particular risk of developing chronic respiratory abnormalities.