Relationship of acute obstructive airway change to chronic (fixed) obstruction

Impact of air quality guidelines on COPD sufferers

Background

COPD is one of the leading causes of morbidity and mortality in both high- and low-income countries and a major public health burden worldwide. While cigarette smoking remains the main cause of COPD, outdoor and indoor air pollution are important risk factors to its etiology. Although studies over the last 30 years helped reduce the values, it is not very clear if the current air quality guidelines are adequately protective for COPD sufferers.

Objective

This systematic review was to summarize the up-to-date literature on the impact of air pollution on the COPD sufferers.

Methods

PubMed and Google Scholar were utilized to search for articles related to our study’s focus. Search terms included “COPD exacerbation”, “air pollution”, “air quality guidelines”, “air quality standards”, “COPD morbidity and mortality”, “chronic bronchitis”, and “air pollution control” separately and in combination. We focused on articles from 1990 to 2015. We also used articles prior to 1990 if they contained relevant information. We focused on articles written in English or with an English abstract. We also used the articles in the reference lists of the identified articles.

Results

Both short-term and long-term exposures to outdoor air pollution around the world are associated with the mortality and morbidity of COPD sufferers even at levels below the current air quality guidelines. Biomass cooking in low-income countries was clearly associated with COPD morbidity in adult nonsmoking females.

Conclusion

There is a need to continue to improve the air quality guidelines. A range of intervention measures could be selected at different levels based on countries’ socioeconomic conditions to reduce the air pollution exposure and COPD burden.

Respiratory Symptoms and Ventilatory Function in Never-Smoking Males Working in Dusty Occupations

AIM: To assess the effect of occupational exposure on respiratory symptoms and ventilatory capacity in never-smoking male workers exposed to mineral or organic dusts.MATERIAL AND METHODS: We performed a cross-sectional study including 138 never-smoking male workers exposed to mineral or organic dust (34 construction workers, 32 furniture manufacturers, 37 agricultural workers, and 35 bakers) and 35 unexposed controls (office workers). Evaluation of all study subjects included completion of a questionnaire and spirometric measurements.RESULTS: The prevalence of the overall respiratory symptoms in the last 12 months was higher in dusty occupation workers than its prevalence in office workers. Statistically significant difference was found between the prevalence of cough in construction workers, agricultural workers and bakers, as well as between the prevalence of phlegm in construction workers, furniture manufacturers and agricultural workers as compared to its prevalence in office workers. The mean values of spirometric parameters were lower in all groups of exposed workers as compared to their mean values in office workers with statistical significance for all measured parameters in construction workers and furniture manufacturers, as well as for small airways indices in agricultural workers and bakers.CONCLUSION: Our findings indicate significant effect of occupational exposure on respiratory symptoms and ventilatory capacity impairment in workers exposed to mineral or organic dusts.

Exposures and cross-shift lung function declines in wildland firefighters

Respiratory problems are common among wildland firefighters. However, there are few studies directly linking occupational exposures to respiratory effects in this population. Our objective was to characterize wildland fire fighting occupational exposures and assess their associations with cross-shift changes in lung function. We studied 17 members of the Alpine Interagency Hotshot Crew with environmental sampling and pulmonary function testing during a large wildfire. We characterized particles by examining size distribution and mass concentration, and conducting elemental and morphological analyses. We examined associations between cross-shift lung function change and various analytes, including levoglucosan, an indicator of wood smoke from burning biomass. The levoglucosan component of the wildfire aerosol showed a predominantly bimodal size distribution: a coarse particle mode with a mass median aerodynamic diameter about 12 μm and a fine particle mode with a mass median aerodynamic diameter < 0.5 μm. Levoglucosan was found mainly in the respirable fraction and its concentration was higher for fire line construction operations than for mop-up operations. Larger cross-shift declines in forced expiratory volume in one second were associated with exposure to higher concentrations of respirable levoglucosan (p < 0.05). Paired analyses of real-time personal air sampling measurements indicated that higher carbon monoxide (CO) concentrations were correlated with higher particulate concentrations when examined by mean values, but not by individual data points. However, low CO concentrations did not provide reliable assurance of concomitantly low particulate concentrations. We conclude that inhalation of fine smoke particles is associated with acute lung function decline in some wildland firefighters. Based on short-term findings, it appears important to address possible long-term respiratory health issues for wildland firefighters. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resources: a file containing additional information on historical studies of wildland fire exposures, a file containing the daily-exposure-severity questionnaire completed by wildland firefighter participants at the end of each day, and a file containing additional details of the investigation of correlations between carbon monoxide concentrations and other measured exposure factors in the current study.].

Longitudinal pulmonary functional loss in cotton textile workers: a 5-year follow-up study

BACKGROUND

Occupational exposure to cotton dust causes several diseases affecting the lungs, but only limited information is available on effects of long-term exposure. In this study, we aimed to evaluate longitudinal changes in selected parameters of pulmonary function in textile workers.

MATERIAL AND METHODS

This prospective cohort study began with 196 textile workers in 2006 and was completed in 2011 with 49 workers. We used standardized tests for pulmonary function on participants on the first day of the workweek in June of 2006 and 2011. Environmental samples of cotton dust were gathered with a vertical elutriator. Loss of pulmonary function was assessed based on gender and smoking status.

RESULTS

The mean number of years participants worked in the textile factory was 7.61 ± 1.83 years, and the mean age was 35.3+5.8 years. The annual FEV1 loss of all workers was 53.2 ml, giving a ratio of annual FEV1 loss to baseline FEV1 of 1.4%. Pulmonary function parameters of all participants in 2011 were significantly lower than those in 2006 (for all, p<0.05). In both surveys, pulmonary function in current smokers was lower, but this difference was not significant (p>0.05).

CONCLUSIONS

This study provides the first data on pulmonary functional loss in Turkish textile workers and supports the findings of other cohort studies that workers with long-term exposure to cotton dust may lose some pulmonary function. The ratio of annual FEV1 loss to baseline FEV1 appears to be a more accurate and comparable method than annual FEV1 loss for evaluating pulmonary functional loss.

Cross-shift and longitudinal changes in FEV1 among wood dust exposed workers

Objectives

Acute lung function (LF) changes might predict an accelerated decline in LF. In this study, we investigated the association between cross-shift and longitudinal changes in forced expiratory volume in 1 s (FEV₁) among woodworkers in a 6-year follow-up study.

Methods

817 woodworkers and 136 controls participated with cross-shift changes of FEV₁ at baseline and FEV₁ and forced vital capacity at follow-up. Height and weight were measured and questionnaire information on respiratory symptoms, employment and smoking habits was collected. Wood dust exposure was assessed from 3572 personal dust measurements at baseline and follow-up. Cumulative wood dust exposure was assessed by a study-specific job exposure matrix and exposure time.

Results

The median (range) of inhalable dust at baseline and cumulative wood dust exposure was 1.0 (0.2–9.8) mg/m³ and 3.8 (0–7.1) mg year/m³, respectively. Mean (SD) for %ΔFEV₁/workday and ΔFEV₁/year was 0.2 (6.0)%, and −29.1 (41.8) ml. Linear regression models adjusting for smoking, age, height and weight change showed no association between cross-shift and annual change in FEV₁ among woodworkers or controls. Including different exposure estimates, atopy or cross-shift change dichotomised or as quartiles did not change the results.

Conclusions

This study among workers exposed to low levels of wood dust does not support an association between acute LF changes and accelerated LF decline.

Prevalence of chronic obstructive pulmonary disease in the U.S. working population: an analysis of data from the 1997-2004 National Health Interview Survey

To estimate the prevalence and the population attributable fraction of chronic obstructive pulmonary disease (COPD) in the U.S. adult workers, we analyzed data obtained from the National Health Interview Surveys for the period 1997-2004. The overall COPD prevalence was 4.0% (95% confidence interval [CI] 3.9-4.1%). The prevalence was higher in females (5.4%, 95% CI 5.3-5.6%) than in males (2.8%, 95% CI 2.7-2.9%); in Whites (4.2%, 95% CI 4.1-4.3%) than in Blacks (3.4%, 95% CI 3.1-3.7%) and other races (2.4%, 95% CI 2.1-2.8%). Compared with insurance, real estate and other finance industry, the top three industries associated with significantly higher prevalence odds ratios (PORs) (adjusted for age, sex, race, and smoking) were other educational services (POR = 1.5, 95% CI 1.0-2.3); transportation equipment (POR = 1.4, 95% CI 1.1-1.8); and social services, religious and membership organizations (POR = 1.4, 95% CI 1.1-1.7). Compared with managers and administrators, except public administration occupation, the top three occupations with significantly higher PORs were health service (1.8, 95% CI 1.5-2.1), other protective service (POR = 1.6, 95% CI 1.2-2.2), and material moving equipment operators (POR = 1.6, 95% CI 1.1-2.3). The overall population attributable fraction for association of COPD with employment was 12.2% for industry and 17.4% for occupation. Further studies are needed to determine specific risk factors associated with COPD in industries and occupations with elevated prevalence and POR.

Cross-shift airway responses and long-term decline in FEV1 in cotton textile workers

RATIONALE

Acute airway response, measured as cross-shift change in FEV(1), to cotton dust may lead to subsequent chronic loss of lung function in exposed workers.

OBJECTIVES

To explore the association between the magnitude and frequency of cross-shift change and chronic loss of FEV(1).

METHODS

Four hundred eight cotton workers and 417 silk workers from Shanghai textile mills were observed prospectively for 20 years, with cross-shift measurements at baseline and follow-up surveys at approximate 5-year intervals. To account for repeated measures of 5-year change, generalized estimating equations were used to estimate the relationship between the magnitude of cross-shift change in FEV(1) (DeltaFEV(1)) and subsequent 5-year annualized change. Linear regression models were used to examine the association between the number of drops in cross-shift FEV(1) (DeltaFEV(1) < 0) and annualized change over the entire study period.

MEASUREMENTS AND MAIN RESULTS

Exposure to cotton dust was associated with a 10 ml/year decrement in 5-year annualized FEV(1) decline. In addition, every 10 ml in DeltaFEV(1) drop was associated with an additional 1.5 ml/year loss in annualized FEV(1) decline. The association between the frequency of drops and annualized decline was stronger for cotton workers than for silk workers over the entire study period.

CONCLUSIONS

Cotton workers had larger and more frequent drops, as well as excessive chronic declines in FEV(1), than did silk workers. The magnitude and frequency of cross-shift drops were associated with chronic loss in FEV(1) over the entire 20-year period examined.

Occupational contribution to the burden of chronic obstructive pulmonary disease

OBJECTIVE

As a past recipient of the Jean Spencer Felton Award for Excellence in Scientific Writing from the Western Occupational and Environmental Medicine Association, it is truly an honor to contribute to this festschrift. What stands out in my mind about Dr Felton is that he loved to delve into the history of occupational medicine and tried to apply the lessons of that history to the modern practice of the discipline. He once wrote that "The name Ramazzini marks the beginning of society's concern with the well-being and physical and emotional health of its workers from the shops of the crafts to the offices of the executives." This review of a common disease for which an occupational contribution is too frequently ignored is offered in the spirit of both the father of modern occupational medicine and one of his 20th-century acolytes.

CONCLUSIONS

The biological plausibility of the capacity of occupational exposures to irritating dusts, gases, and fumes to cause chronic obstructive pulmonary disease (COPD) is high. Epidemiological evidence from both worker cohort and community studies supports an increased risk of COPD associated with such exposures. The occupational contribution to the burden of COPD is sufficiently great that preventive interventions are warranted.

Is Chronic Airway Obstruction From Cotton Dust Exposure Reversible?

BACKGROUND

Exposure to cotton dust is known to cause chronic airway obstruction, but there is little information on whether the obstructive impairment is reversible after the exposure stops.

METHODS

Longitudinal changes in lung function were evaluated among 429 cotton textile workers and 449 silk workers in Shanghai, China, beginning in 1981. Both active and retired workers were tested every 4 to 6 years for 15 years.

RESULTS

Overall, cotton workers had greater annual declines in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Compared with active workers, retired cotton workers had lower annual loss of FEV1, although the retired workers had a greater loss during their active employment than the currently active workers. No such trends were detected in silk workers. Annual declines in FEV1 in retired cotton workers were smaller with increasing time since retirement. Multivariate analysis showed that retirement was a substantial contributing factor for improved FEV1 and FVC in the cotton workers, especially among those who did not smoke. Correspondingly, remission of airflow obstruction, defined as a ratio of FEV1 and FVC of less than 70%, was more common in retirees than in the active workers, and more common in nonsmokers than in smokers.

CONCLUSION

Chronic airway obstruction related to long-term exposure to cotton dust may be partially reversible after the exposure ceases, although lung function does not return to the level found in unexposed workers.

Role of underlying pulmonary obstruction in short-term airway response to metal working fluid exposure: a reanalysis

BACKGROUND

Among epidemiologic studies that found evidence for associations between exposures to metal working fluids (MWF) and pulmonary function impairments, one found effects restricted to workers with fixed obstruction at baseline. We reanalyzed a previously published study on MWF exposure and cross-shift pulmonary function to further evaluate this finding.

METHODS

Pulmonary function was measured cross-shift on Monday and Friday in 131 male automotive workers. Quantitative personal MWF exposure data were available. Those with an FEV(1)/FVC ratio of <or=0.72 were considered obstructed.

RESULTS

There was a trend towards increasing incidence of cross-shift decrement in FEV(1) as MWF exposure increased in the full cohort as well as when the results were restricted to the 19 (14.5%) who were obstructed. Those with obstruction were slightly more likely to show decrements in FEV(1) on Fridays. Removing the obstructed subgroup did not appear to substantially weaken the exposure-response relation.

CONCLUSIONS

No important differences were found in cross-shift effects of MWF between obstructed and non-obstructed workers.

Occupational airways diseases from chronic low-level exposures to irritants

Short-term, high-level exposures to dusts, gases, mists, fumes, and smoke that are irritating to the respiratory tract are capable of inducing asthma, the so-called reactive airways dysfunction syndrome. Such exposures, however, do not occur frequently; chronic or recurrent exposures to lower levels of irritants are much more common. This article reviews the evidence that supports the concept that low-level exposures to respiratory tract irritants can contribute to the development of chronic obstructive pulmonary disease and asthma.

Agravos respiratórios decorrentes da atividade agrícola

As doenças respiratórias são um importante problema crítico para trabalhadores rurais, uma vez constatada evidência de aumento significativo do risco de morbidade e mortalidade, por problemas respiratórios, em trabalhadores agrícolas. Este fato é de grande importância especialmente nos países em desenvolvimento, onde grande parte da população depende da agricultura como fonte de subsistência. Sabidamente, pessoas envolvidas em atividades agrícolas estão potencialmente expostas a vários agentes como poeira inorgânica do solo, poeira orgânica, gases tóxicos, pesticidas, etc. O aparelho respiratório pode reagir a estes insultos ao nível de vias aéreas superiores com rinite, sinusite e otite. As vias aéreas inferiores podem responder desencadeando ou agravando asma brônquica, com o quadro conhecido como síndrome asthma-like, com obstrução crônica e lesões causadas por poeira orgânica, pneumonite por hipersensibilidade e fibrose intersticial. Assim, se faz necessário uma identificação precisa dos possíveis agentes etiológicos e conseqüentes medidas profiláticas das doenças respiratórias decorrentes da atividade agrícola.

Two year follow up of pulmonary function values among welders in New Zealand

OBJECTIVES

To examine whether welding is a risk factor for an accelerated decline in pulmonary function.

METHODS

2 Year follow up of pulmonary function and respiratory symptoms among 54 welders and 38 non-welders in eight New Zealand welding sites.

RESULTS

There were no significant differences in age, height, smoking habits, ethnicity, or total time in industrial work between welders and non-welders. No overall differences were noted in the changes of pulmonary function variables between the two study groups. However, when the comparison was restricted to smokers, welders had a significantly greater (p = 0.02) annual decline (88.8 ml) in FEV1 than non-welders, who had a slight non-significant annual increase (34.2 ml). Also, welders without respiratory protection or local exhaust ventilation while welding had a greater annual decline both in forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) than welders with protection (p = 0.001 and 0.04, respectively). Among welders a significant association was found between the acute across shift change and the annual decline in FEV1. Chronic bronchitis was more common among welders (24%) than non-welders (5%). Only one welder (2%) but eight non-welders (21%) reported having asthma.

CONCLUSIONS

Welders who smoked and welders working without local exhaust ventilation or respiratory protection have an increased risk of accelerated decline in FEV1.