Occupational airborne exposure and the incidence of respiratory symptoms and asthma

Comorbidities and Causes of Death of Patients With Asbestosis

OBJECTIVE

Comorbidities are common and affect the prognosis of patients with interstitial lung diseases, but few previous studies have investigated patients with asbestosis.

METHODS

We collected comorbidities and death causes of 116 patients with asbestosis treated in Oulu University Hospital. Causes of death were confirmed by autopsy in 68% of the cases.

RESULTS

The most common comorbidities of asbestosis patients were pleural plaques (96%) and coronary artery disease (CAD; 67%). The prevalence of rheumatoid arthritis was 8.6%. The most common underlying causes of death were asbestosis (36%), CAD (24%), and lung cancer (LC) (10%). CAD and LC were associated with shorter survival in adjusted analyses.

CONCLUSIONS

Patients with asbestosis have multiple comorbidities. Prevention and treatment of CAD and LC may influence the prognosis of asbestosis patients.

Mortality Associated With Occupational Exposure in Helsinki, Finland-A 24-Year Follow-up

OBJECTIVES

Our objective was to study mortality related to different obstructive lung diseases, occupational exposure, and their potential joint effect in a large, randomized population-based cohort.

METHODS

We divided the participants based on the answers to asthma and chronic obstructive pulmonary disease (COPD) diagnoses and occupational exposure and used a combined effects model and compared the results to no asthma or COPD with no occupational exposure.

RESULTS

High exposure had a hazards ratio (HR) of 1.34 (1.11-1.62) and asthma and COPD coexistence of 1.58 (1.10-2.27). The combined effects of intermediate exposure and coexistence had an HR of 2.20 (1.18-4.09), high exposure with coexistence of 1.94 (1.10-3.42) for overall mortality, and sub-HR for respiratory-related mortality of 3.21 (1.87-5.50).

CONCLUSIONS

High occupational exposure increased overall but not respiratory-related mortality hazards, while coexisting asthma and COPD overall and respiratory-related hazards of mortality.

Association of respiratory symptoms with body mass index and occupational exposure comparing sexes and subjects with and without asthma: follow-up of a Norwegian population study (the Telemark study)

BACKGROUND

Occupational exposure and increased body mass index (BMI) are associated with respiratory symptoms. This study investigated whether the association of a respiratory burden score with changes in BMI as well as changes in occupational exposure to vapours, gas, dust and fumes (VGDF) varied in subjects with and without asthma and in both sexes over a 5-year period.

METHODS

In a 5-year follow-up of a population-based study, 6350 subjects completed a postal questionnaire in 2013 and 2018. A respiratory burden score based on self-reported respiratory symptoms, BMI and frequency of occupational exposure to VGDF were calculated at both times. The association between change in respiratory burden score and change in BMI or VGDF exposure was assessed using stratified regression models.

RESULTS

Changes in respiratory burden score and BMI were associated with a β-coefficient of 0.05 (95% CI 0.04 to 0.07). This association did not vary significantly by sex, with 0.05 (0.03 to 0.07) for women and 0.06 (0.04 to 0.09) for men. The association was stronger among those with asthma (0.12; 0.06 to 0.18) compared with those without asthma (0.05; 0.03 to 0.06) (p=0.011). The association of change in respiratory burden score with change in VGDF exposure gave a β-coefficient of 0.15 (0.05 to 0.19). This association was somewhat greater for men versus women, with coefficients of 0.18 (0.12 to 0.24) and 0.13 (0.07 to 0.19), respectively (p=0.064). The estimate was similar among subjects with asthma (0.18; -0.02 to 0.38) and those without asthma (0.15; 0.11 to 0.19).

CONCLUSIONS

Increased BMI and exposure to VGDF were associated with increased respiratory burden scores. The change due to increased BMI was not affected by sex, but subjects with asthma had a significantly larger change than those without. Increased frequency of VGDF exposure was associated with increased respiratory burden score but without statistically significant differences with respect to sex or asthma status.

Epidemiology of wheeze among preschool children: a population-based cross-sectional study from rural Sri Lanka

OBJECTIVES

To assess the prevalence of wheeze and factors associated with its severity among 3-6 years old children.

METHODOLOGY

DESIGN: A population-based, cross-sectional study using the WHO 30 cluster methodology with probability proportionate to size sampling.

SETTING

36 preschools registered at the divisional secretariat offices of Anuradhapura district, Sri Lanka.

PARTICIPANTS

We recruited 1060 preschool children from 36 preschools aged 3-6 years.

MAIN OUTCOME MEASUREMENTS

We used the International Study of Asthma and Allergy in Childhood questionnaire to assess the prevalence, symptomatology and associated factors of wheeze.

RESULTS

The study sample consisted of 548 (51.70%) male and 512 (48.30%) female children with a mean age of 4.41 (±0.66) years. At least one wheezing episode ever was reported in 323 (30.47%; 95% CI 27.71% to 33.34%) children and 247 (23.30%; 95% CI 20.79% to 25.97%) children had a wheezing attack in the preceding year. Severe episodes of wheezing were reported in 76 (7.17%; 95% CI 5.69% to 8.89%) participants. However, only 27 (35.53%; 95% CI 24.88% to 47.34%) children with severe wheezing had been diagnosed as asthmatics by a clinician. The identified independent risk factors for severe wheeze were allergic rhinitis (OR 6.90; 95% CI 3.84 to 12.40), domestic dog(s) (OR 2.34; 95% CI 1.01 to 5.40), frequent consumption of skipjack tuna (OR 1.94; 95% CI 1.11 to 3.39) and passive smoking (OR 1.70; 95% CI 0.93 to 3.11) while living in a house with a cement floor is a protective factor (OR 0.41; 95% CI 0.21 to 0.80).

CONCLUSION

Wheezing commonly affects one-fourth of preschool children in rural Sri Lanka. Severe wheezing is often not diagnosed as asthma despite frequent symptoms, probably due to hesitancy in labelling preschool children as asthmatics. Allergic rhinitis, domestic dogs, frequent consumption of Skipjack tuna fish and exposure to passive smoking were independent risk factors for severe wheeze.

Airborne occupational exposures and the risk of developing respiratory symptoms and airway obstruction in the Lifelines Cohort Study

OBJECTIVES

To date, only a few studies have investigated the associations between occupational exposures and respiratory outcomes longitudinally in the general population. We investigated the associations between occupational exposures and the development of respiratory symptoms and airway obstruction in the Lifelines Cohort Study.

METHODS

We included 35 739 occupationally active subjects with data on chronic cough, chronic phlegm, chronic bronchitis or airway obstruction at baseline and approximately 4.5 years follow-up. Exposures to biological dust, mineral dust, gases/fumes, pesticides, solvents and metals in the current job at baseline were estimated with the ALOHA+job-exposure matrix (JEM). Airway obstruction was defined as FEV1/FVC below the lower limit of normal. Logistic regression analysis adjusted for baseline covariates was used to investigate the associations.

RESULTS

At follow-up, 1888 (6.0%), 1495 (4.7%), 710 (2.5%) and 508 (4.5%) subjects had developed chronic cough, chronic phlegm, chronic bronchitis and airway obstruction, respectively. High exposure to biological dust was associated with a higher odds to develop chronic cough and chronic bronchitis. High exposure to pesticides was associated with a higher odds for the development of all respiratory symptoms and airway obstruction. In the multiple exposures analyses, only the association between pesticides exposure and respiratory symptoms remained.

CONCLUSIONS

Subjects exposed to high pesticides had a higher odds to develop respiratory symptoms on average 4.5 years later. Control measures should be taken to reduce pesticides exposure among the working population to prevent respiratory symptoms and airway obstruction.

Occupational exposures and genetic susceptibility to occupational exposures are related to sickness absence in the Lifelines cohort study

In this cross-sectional study, we investigated the association between occupational exposures and sickness absence (SA), the mediating role of respiratory symptoms, and whether genetic susceptibility to SA upon occupational exposures exists. Logistic regression was used to examine associations and structural equation modelling was used for mediation analyses. Genetic susceptibility was investigated by including interactions between occupational exposures and 11 candidate single nucleotide polymorphisms (SNPs). Biological dust, mineral dust, and pesticides exposure were associated with a lower prevalence of any SA (OR (95% CI) = 0.72 (0.58-0.89), 0.88 (0.78-0.99), and 0.70 (0.55-0.89), respectively) while gases/fumes exposure was associated with a higher prevalence of long-term SA (1.46 (1.11-1.91)). Subjects exposed to solvents and metals had a higher prevalence of any (1.14 (1.03-1.26) and 1.68 (1.26-2.24)) and long-term SA (1.26 (1.08-1.46) and 1.75 (1.15-2.67)). Chronic cough and chronic phlegm mediated the association between high gases/fumes exposure and long-term SA. Two of 11 SNPs investigated had a positive interaction with exposure on SA and one SNP negatively interacted with exposure on SA. Exposure to metals and gases/fumes showed a clear dose-response relationship with a higher prevalence of long-term SA; contrary, exposure to pesticides and biological/mineral dust showed a protective effect on any SA. Respiratory symptoms mediated the association between occupational exposures and SA. Moreover, gene-by-exposure interactions exist.

The Occupational Burden of Nonmalignant Respiratory Diseases. An Official American Thoracic Society and European Respiratory Society Statement

Rationale: Workplace inhalational hazards remain common worldwide, even though they are ameliorable. Previous American Thoracic Society documents have assessed the contribution of workplace exposures to asthma and chronic obstructive pulmonary disease on a population level, but not to other chronic respiratory diseases. The goal of this document is to report an in-depth literature review and data synthesis of the occupational contribution to the burden of the major nonmalignant respiratory diseases, including airway diseases; interstitial fibrosis; hypersensitivity pneumonitis; other noninfectious granulomatous lung diseases, including sarcoidosis; and selected respiratory infections. Methods: Relevant literature was identified for each respiratory condition. The occupational population attributable fraction (PAF) was estimated for those conditions for which there were sufficient population-based studies to allow pooled estimates. For the other conditions, the occupational burden of disease was estimated on the basis of attribution in case series, incidence rate ratios, or attributable fraction within an exposed group. Results: Workplace exposures contribute substantially to the burden of multiple chronic respiratory diseases, including asthma (PAF, 16%); chronic obstructive pulmonary disease (PAF, 14%); chronic bronchitis (PAF, 13%); idiopathic pulmonary fibrosis (PAF, 26%); hypersensitivity pneumonitis (occupational burden, 19%); other granulomatous diseases, including sarcoidosis (occupational burden, 30%); pulmonary alveolar proteinosis (occupational burden, 29%); tuberculosis (occupational burden, 2.3% in silica-exposed workers and 1% in healthcare workers); and community-acquired pneumonia in working-age adults (PAF, 10%). Conclusions: Workplace exposures contribute to the burden of disease across a range of nonmalignant lung conditions in adults (in addition to the 100% burden for the classic occupational pneumoconioses). This burden has important clinical, research, and policy implications. There is a pressing need to improve clinical recognition and public health awareness of the contribution of occupational factors across a range of nonmalignant respiratory diseases.

18-yr cumulative incidence of respiratory/allergic symptoms/diseases and risk factors in the Pisa epidemiological study

BACKGROUND

Few population-based studies on the effects of environmental exposure variation exist.

AIM

Assessing respiratory symptom/disease incidence related to risk factor exposure changes.

METHODS

A longitudinal general population sample from two surveys (PISA2:1991-1993; PISA3:2009-2011; no. = 970), aged ≥20 years at baseline, completed a questionnaire on respiratory symptoms/diseases, risk factor exposure and performed spirometry. 18-year follow-up cumulative incidence of respiratory symptoms/diseases and longitudinal changes (persistence, incidence, remittance) in risk factor exposure were computed.

RESULTS

Cumulative incidence values were: 3.2% (corresponding to a 1.8‰/year incidence rate), asthma; 6.6% (3.8‰/year), asthma attacks; 4.5% (2.6‰/year), wheeze; 31.7% (21.0‰/year), allergic rhinitis-AR; 7.6% (4.4‰/year), chronic obstructive pulmonary disease-COPD; 16.1% (9.7‰/year), usual cough; 18.5% (11.3‰/year), usual phlegm; 30.7% (20.1‰/year), dyspnoea 1+; 13.9% (8.3‰/year), airway obstruction. The following associations emerged among respiratory symptom/disease cumulative incidence and risk factor exposure changes: a two-to-five fold higher risk for COPD, phlegm, cough, dyspnoea, asthma attacks, airway obstruction in persistent smokers; a two-to-three fold higher risk for COPD in remittent smokers; a two-fold higher risk for AR, phlegm and a four-fold higher risk for asthma in subjects with persistent occupational exposure; a two-fold higher risk for cough, phlegm, dyspnoea, AR in subjects with incident occupational exposure; a two-fold higher risk for AR, asthma attacks, COPD in subjects with incident traffic exposure.

CONCLUSIONS

Our study showed noteworthy respiratory symptom/disease incidence values and indicated that life-style and environmental exposure changes can differently influence onset. This information could be useful for primary prevention strategies in order to reduce the chronic disease burden in the general population.

The Secretory Response of Rat Peritoneal Mast Cells on Exposure to Mineral Fibers

BACKGROUND

Exposure to mineral fibers is of substantial relevance to human health. A key event in exposure is the interaction with inflammatory cells and the subsequent generation of pro-inflammatory factors. Mast cells (MCs) have been shown to interact with titanium oxide (TiO₂) and asbestos fibers. In this study, we compared the response of rat peritoneal MCs challenged with the asbestos crocidolite and nanowires of TiO₂ to that induced by wollastonite employed as a control fiber.

METHODS

Rat peritoneal MCs (RPMCs), isolated from peritoneal lavage, were incubated in the presence of mineral fibers. The quantities of secreted enzymes were evaluated together with the activity of fiber-associated enzymes. The ultrastructural morphology of fiber-interacting RPMCs was analyzed with electron microscopy.

RESULTS

Asbestos and TiO₂ stimulate MC secretion. Secreted enzymes bind to fibers and exhibit higher activity. TiO₂ and wollastonite bind and improve enzyme activity, but to a lesser degree than crocidolite.

CONCLUSIONS

(1) Mineral fibers are able to stimulate the mast cell secretory process by both active (during membrane interaction) and/or passive (during membrane penetration) interaction; (2) fibers can be found to be associated with secreted enzymes-this process appears to create long-lasting pro-inflammatory environments and may represent the active contribution of MCs in maintaining the inflammatory process; (3) MCs and their enzymes should be considered as a therapeutic target in the pathogenesis of asbestos-induced lung inflammation; and (4) MCs can contribute to the inflammatory effect associated with selected engineered nanomaterials, such as TiO₂ nanoparticles.

Different risk factor patterns for adult asthma, rhinitis and eczema: results from West Sweden Asthma Study

BACKGROUND

Atopic diseases including asthma, rhinitis and eczema have increased in the second half of the past century. This has been well studied among children and adolescents but with the exception of asthma to a much lesser extent in adults. The adult risk factor pattern of atopic diseases, in particular of eczema, and their relation to allergic sensitization are yet to be fully elucidated. Studies among adults that have compared the risk factor pattern for these conditions in the same material are very few. The objective of this study was to compare the risk factor patterns for asthma, rhinitis and eczema in a randomly selected adult population.

METHODS

A questionnaire survey on atopic diseases was dispatched by mail to 30,000 randomly selected individuals in West Sweden aged 16-75 years and 62 % participated. A subgroup of 2000 individuals was selected for clinical examinations including blood sampling for specific serum Immunoglobulin E to common airborne allergens and 1172 attended.

RESULTS

The prevalence of current asthma was 11.8 %, current rhinitis 42.8 %, current eczema 13.5 and 2.3 % had all three conditions while 13.9 % had at least two conditions. No mutual risk factor was identified for all three conditions. Allergic sensitization was a strong risk factor for current asthma (OR 4.1 CI 2.7-6.3) and current rhinitis (OR 5.1 CI 3.8-6.9) but not so for current eczema. Obesity was a risk factor for current asthma and current rhinitis, while farm childhood decreased the risk for current asthma and current rhinitis. Occupational exposure to gas dust or fumes and female sex was associated with an increased risk of current asthma and current eczema.

CONCLUSIONS

There are different risk factor patterns for asthma, rhinitis and eczema in adults but some risk factors are overlapping between some of the conditions. The effect of mutable risk factors should be assessed further in longitudinal studies.

Non-response in a cross-sectional study of respiratory health in Norway

OBJECTIVES

Declining participation in epidemiological studies has been reported in recent decades and may lead to biased prevalence estimates and selection bias. The aim of the study was to identify possible causes and effects of non-response in a population-based study of respiratory health in Norway.

DESIGN

The Telemark study is a longitudinal study that began with a cross-sectional survey in 2013.

SETTING

In 2013, a random sample of 50,000 inhabitants aged 16-50 years, living in Telemark county, received a validated postal questionnaire. The response rate was 33%. In this study, a random sample of 700 non-responders was contacted first by telephone and then by mail.

OUTCOME MEASURES

Response rates, prevalence and OR of asthma and respiratory symptoms based on exposure to vapours, gas, dust or fumes (VGDF) and smoking. Causes of non-response.

RESULTS

A total of 260 non-responders (37%) participated. Non-response was associated with younger age, male sex, living in a rural area and past smoking. The prevalence was similar for responders and non-responders for physician-diagnosed asthma and several respiratory symptoms. The prevalence of chronic cough and use of asthma medication was overestimated in the Telemark study, and adjusted prevalence estimates were 17.4% and 5%, respectively. Current smoking was identified as a risk factor for respiratory symptoms among responders and non-responders, while occupational VGDF exposure was a risk factor only among responders. The Breslow-Day test detected heterogeneity between productive cough and occupational VGDF exposure among responders.

CONCLUSIONS

The Telemark study provided valid estimates for physician-diagnosed asthma and several respiratory symptoms, while it was necessary to adjust prevalence estimates for chronic cough and use of asthma medication. Reminder letters had little effect on risk factor associations. Selection bias should be considered in future investigations of the relationship between respiratory outcomes and exposures.

The Urban-Rural Gradient In Asthma: A Population-Based Study in Northern Europe

The early life environment appears to have a persistent impact on asthma risk. We hypothesize that environmental factors related to rural life mediate lower asthma prevalence in rural populations, and aimed to investigate an urban-rural gradient, assessed by place of upbringing, for asthma. The population-based Respiratory Health In Northern Europe (RHINE) study includes subjects from Denmark, Norway, Sweden, Iceland and Estonia born 1945–1973. The present analysis encompasses questionnaire data on 11,123 RHINE subjects. Six categories of place of upbringing were defined: farm with livestock, farm without livestock, village in rural area, small town, city suburb and inner city. The association of place of upbringing with asthma onset was analysed with Cox regression adjusted for relevant confounders. Subjects growing up on livestock farms had less asthma (8%) than subjects growing up in inner cities (11%) (hazard ratio 0.72 95% CI 0.57–0.91), and a significant urban-rural gradient was observed across six urbanisation levels (p = 0.02). An urban-rural gradient was only evident among women, smokers and for late-onset asthma. Analyses on wheeze and place of upbringing revealed similar results. In conclusion, this study suggests a protective effect of livestock farm upbringing on asthma development and an urban-rural gradient in a Northern European population.

Meteorological conditions, climate change, new emerging factors, and asthma and related allergic disorders. A statement of the World Allergy Organization

The prevalence of allergic airway diseases such as asthma and rhinitis has increased dramatically to epidemic proportions worldwide. Besides air pollution from industry derived emissions and motor vehicles, the rising trend can only be explained by gross changes in the environments where we live. The world economy has been transformed over the last 25 years with developing countries being at the core of these changes. Around the planet, in both developed and developing countries, environments are undergoing profound changes. Many of these changes are considered to have negative effects on respiratory health and to enhance the frequency and severity of respiratory diseases such as asthma in the general population.

Increased concentrations of greenhouse gases, and especially carbon dioxide (CO₂), in the atmosphere have already warmed the planet substantially, causing more severe and prolonged heat waves, variability in temperature, increased air pollution, forest fires, droughts, and floods – all of which can put the respiratory health of the public at risk. These changes in climate and air quality have a measurable impact not only on the morbidity but also the mortality of patients with asthma and other respiratory diseases. The massive increase in emissions of air pollutants due to economic and industrial growth in the last century has made air quality an environmental problem of the first order in a large number of regions of the world. A body of evidence suggests that major changes to our world are occurring and involve the atmosphere and its associated climate. These changes, including global warming induced by human activity, have an impact on the biosphere, biodiversity, and the human environment. Mitigating this huge health impact and reversing the effects of these changes are major challenges.

This statement of the World Allergy Organization (WAO) raises the importance of this health hazard and highlights the facts on climate-related health impacts, including: deaths and acute morbidity due to heat waves and extreme meteorological events; increased frequency of acute cardio-respiratory events due to higher concentrations of ground level ozone; changes in the frequency of respiratory diseases due to trans-boundary particle pollution; altered spatial and temporal distribution of allergens (pollens, molds, and mites); and some infectious disease vectors. According to this report, these impacts will not only affect those with current asthma but also increase the incidence and prevalence of allergic respiratory conditions and of asthma. The effects of climate change on respiratory allergy are still not well defined, and more studies addressing this topic are needed. Global warming is expected to affect the start, duration, and intensity of the pollen season on the one hand, and the rate of asthma exacerbations due to air pollution, respiratory infections, and/or cold air inhalation, and other conditions on the other hand.

Gas, dust, and fumes exposure is associated with mite sensitization and with asthma in mite-sensitized adults

Occupational exposure to gas, dust, and fumes (GDF) increases the risk of asthma and eczema. We investigated the role of sensitization in the association between GDF and allergic conditions. A population-based sample of 788 adults from the West Sweden Asthma Study completed questionnaires and skin prick tests. After adjustment for confounders, GDF exposure was associated with a doubled risk of sensitization to mites, but not with other allergens. Mite sensitization also modified the effect of GDF on asthma. In mite-sensitized subjects, GDF was associated with physician-diagnosed asthma, adjusted OR 2.9 (1.2-7.2), and with wheeze, OR 2.4 (1.1-5.3). In non-mite-sensitized subjects, the corresponding ORs were 1.1 (0.5-2.6) and 0.6 (0.3-1.3). GDF was independently associated with eczema regardless of mite sensitization, but not with rhinitis. These novel findings suggest that components of GDF may act as adjuvants that facilitate sensitization to mites and that mite-sensitized individuals may be especially susceptible to inhalant occupational exposures.

Changes in prevalence of chronic obstructive pulmonary disease and asthma in the US population and associated risk factors

Chronic lower airway diseases, including chronic obstructive pulmonary disease (COPD) and asthma, are currently the third leading cause of death in the United States. We aimed to evaluate changes in prevalence of and risk factors for COPD and asthma among the US adult population. We evaluated changes in prevalence of self-reported doctor-diagnosed COPD (i.e. chronic bronchitis and emphysema) and asthma and self-reported respiratory symptoms comparing data from the 1988-1994 and 2007-2010 National Health and Nutrition Examination Surveys. To investigate changes in the severity of each outcome over the two periods, we calculated changes in the proportions of spirometry-based airflow obstruction for each outcome. Prevalence of doctor-diagnosed chronic bronchitis and emphysema decreased significantly mainly among males, while asthma increased only among females. The self-reported disease and the respiratory symptoms were associated with increased prevalence of airflow obstruction for both periods. However, the prevalence of airflow obstruction decreased significantly in the second period among those with shortness of breath and doctor-diagnosed respiratory conditions (chronic bronchitis, emphysema, and asthma). COPD outcomes and asthma were associated with lower education, smoking, underweight and obesity, and occupational dusts and fumes exposure. Chronic lower airway diseases continue to be major public health problems. However, decreased prevalence of doctor-diagnosed chronic bronchitis and emphysema (in males) and decreased prevalence of airflow obstruction in those with respiratory symptoms and doctor-diagnosed respiratory diseases may indicate a declining trend and decrease in disease severity between the two periods. Continued focus on prevention of these diseases through public health interventions is prudent.

Variability and consistency in lung inflammatory responses to particles with a geogenic origin

BACKGROUND AND OBJECTIVE

Particulate matter <10 μm (PM10 ) is well recognized as being an important driver of respiratory health; however, the impact of PM10 of geogenic origin on inflammatory responses in the lung is poorly understood. This study aimed to assess the lung inflammatory response to community sampled geogenic PM10 .

METHODS

This was achieved by collecting earth material from two regional communities in Western Australia (Kalgoorlie-Boulder and Newman), extracting the PM10 fraction and exposing mice by intranasal instillation to these particles. The physicochemical characteristics of the particles were assessed and lung inflammatory responses were compared to control particles. The primary outcomes were cellular influx and cytokine production in the lungs of the exposed mice.

RESULTS

The physical and chemical characteristics of the PM10 from Kalgoorlie and Newman differed with the latter having a higher concentration of Fe and a larger median diameter. Control particles (2.5 μm polystyrene) caused a significant influx of inflammatory cells (neutrophils) with little production of proinflammatory cytokines. In contrast, the geogenic particles induced the production of MIP-2, IL-6 and a significant influx of neutrophils. Qualitatively, the response following exposure to particles from Kalgoorlie and Newman were consistent; however, the magnitude of the response was substantially higher in the mice exposed to particles from Newman.

CONCLUSIONS

The unique physicochemical characteristics of geogenic particles induced a proinflammatory response in the lung. These data suggest that particle composition should be considered when setting community standards for PM exposure, particularly in areas exposed to high geogenic particulate loads.

Occupations with an increased prevalence of self-reported asthma in Indian adults

Objectives

Occupational asthma remains relatively under-recognized in India with little or no information regarding preventable causes. We studied occupations with an increased prevalence of self-reported asthma among adult men and women in India.

Methods

Analysis is based on 64 725 men aged 15–54 years and 52 994 women aged 15–49 years who participated in India’s third National Family Health Survey, 2005–2006, and reported their current occupation. Prevalence odds ratios (ORs) for specific occupations and asthma were estimated using multivariate logistic regression, separately for men and women, adjusting for age, education, household wealth index, current tobacco smoking, cooking fuel use, rural/urban residence and access to healthcare.

Results

The prevalence of asthma among the working population was 1.9%. The highest odds ratios for asthma were found among men in the plant and machine operators and assemblers major occupation category (OR: 1.67; 95% CI: 1.14–2.45; p = 0.009). Men working in occupation subcategories of machine operators and assemblers (OR: 1.85; 95% CI: 1.24–2.76; p = 0.002) and mining, construction, manufacturing and transport (OR: 1.33; 95% CI: 1.00–1.77; p = 0.051) were at the highest risk of asthma. Reduced odds of asthma prevalence in men was observed among extraction and building trades workers (OR: 0.72; 95% CI: 0.53–0.97; p = 0.029). Among women none of the occupation categories or subcategories was found significant for asthma risk. Men and women employed in high-risk occupations were not at a higher risk of asthma when compared with those in low-risk occupations.

Conclusions

This large population-based, nationally representative cross-sectional study has confirmed findings from high income countries showing high prevalence of asthma in men in a number of occupational categories and subcategories; however, with no evidence of increased risks for women in the same occupations.

Indoor particle counts during Asian dust events under everyday conditions at an apartment in Japan

OBJECTIVE

Asian dust storms originating from arid regions of Mongolia and China are a well-known springtime phenomenon throughout East Asia. Evidence is increasing for the adverse health effects caused by airborne desert dust inhalation. Given that people spend approximately 90 % of their time indoors, indoor air quality is a significant concern. The present study aimed to examine the influence of outdoor particulate matter (PM) levels on indoor PM levels during Asian dust events under everyday conditions.

METHODS

We simultaneously monitored counts of particles larger than 0.3, 0.5, 1, 2, and 5 μm using two direct-reading instruments (KC-01D1 airborne particle counter; Rion), one placed in an apartment room and another on the veranda, under everyday conditions before and during an Asian dust event. We also examined how indoor particle counts were affected by opening a window, crawling, and air purifier use.

RESULTS

An Asian dust event on 24 April 2012 caused 50- and 20-fold increases in PM counts in outdoor and indoor air, respectively. A window open for 10 min resulted in a rapid increase of indoor PM counts up to 70 % of outside levels that did not return to baseline levels after 3 h. An air purifier rapidly reduced PM counts for all particle sizes measured.

CONCLUSIONS

It is important to account for occupant behavior, such as window-opening and air purifier use, when estimating residential exposure to particulate matter.

Occupation and the prevalence of respiratory health symptoms and conditions: the Atherosclerosis Risk in Communities Study

OBJECTIVES

To examine associations between occupation and respiratory health in a large, population-based cohort of adults in the United States.

METHODS

Data from 15,273 participants, aged 45 to 64 years, in the Atherosclerosis Risk in Communities study were used to examine associations of current or most recent job held with the prevalence of self-reported chronic cough, chronic bronchitis, wheezing, asthma, and measures of lung function collected by spirometry.

RESULTS

Eleven percent of participants reported wheezing and 9% were classified as having airway obstruction. Compared with individuals in managerial and administrative jobs, increased prevalences of respiratory outcomes were observed among participants in selected occupations, including construction and extractive trades (wheezing, prevalence ratio = 1.92, 95% confidence interval = 1.35, 2.73; airway obstruction, prevalence ratio = 1.31, 95% confidence interval = 1.05, 1.65).

CONCLUSIONS

Specific occupations are associated with adverse respiratory health.

The incidence of work-related asthma-like symptoms and dust exposure in Norwegian smelters

RATIONALE

The prevalence of respiratory symptoms among employees in smelters is positively associated with dust exposure.

OBJECTIVES

To investigate the association between the incidence of work-related asthma-like symptoms (WASTH) and dust exposure.

METHODS

All the employees were invited to participate in a 5-year longitudinal study. The outcome of WASTH was defined as the combination of dyspnea and wheezing improving on rest days or vacation in an individual who had no asthma previously. Information about smoking and occupational status was obtained from a questionnaire. A job exposure matrix of total dust was developed. Multivariate data analyses were performed using Cox regression.

MEASUREMENTS AND MAIN RESULTS

The total follow-up time of the employees (n = 2,476) was 8,469 years, and the median follow-up time for participants was 4.0 years. During the follow-up, 91 employees developed WASTH, and the corresponding incidence rate for WASTH per 1,000 person-years was 8.9 (7.3-10.9) (95% confidence interval in parentheses). The risk ratio of WASTH increased significantly (P = 0.0001) with dust exposure in the middle and high categories (1.0-2.9 and ≥ 3.0 mg/m(3)). Stratified analyses showed that the effect of current dust exposure varied with both previous exposure (PE) to dust and fumes (P = 0.006) and airflow limitation (AFL) (P = 0.033). The final analyses showed that the risk ratios for WASTH per 1 mg/m(3) increase in current dust exposure were 1.1 (0.93-1.2), 1.4 (1.1-1.8), 1.6 (1.1-2.3), and 1.9 (1.2-3.0) for the categories (PE+/AFL-), (PE-/AFL-), (PE+/AFL+, and (PE-/AFL+).

CONCLUSIONS

In conclusion, dust exposure was associated with an increased incidence of WASTH.

Urban city transportation mode and respiratory health effect of air pollution: a cross-sectional study among transit and non-transit workers in Nigeria

OBJECTIVES

To assess the respiratory health effect of city ambient air pollutants on transit and non-transit workers and compare such effects by transportation mode, occupational exposure and sociodemographic characteristics of participants.

DESIGN

Cross-sectional, randomised survey.

SETTING

A two primary healthcare centre survey in 2009/2010 in Uyo metropolis, South-South Nigeria.

PARTICIPANTS

Of the 245 male participants recruited, 168 (50 taxi drivers, 60 motorcyclists and 58 civil servants) met the inclusion criteria. These include age 18-35 years, a male transit worker or civil servant who had worked within Uyo metropolis for at least a year prior to the study, and had no history of respiratory disorders/impairment or any other debilitating illness.

MAIN OUTCOME MEASURE

The adjusted ORs for respiratory function impairment (force vital capacity (FVC) and/or FEV(1)<80% predicted or FEV(1)/FVC<70% predicted) using Global Initiative for Chronic Obstructive Lung Diseases (GOLD) and National Institute for Health and Clinical Excellence (NICE) criteria were calculated. In order to investigate specific occupation-dependent respiratory function impairment, a comparison was made between the ORs for respiratory impairment in the three occupations. Adjustments were made for some demographic variables such as age, BMI, area of residence, etc.

RESULTS

Exposure to ambient air pollution by occupation and transportation mode was independently associated with respiratory functions impairment and incident respiratory symptoms among participants. Motorcyclists had the highest effect, with adjusted OR 3.10, 95% CI 0.402 to 16.207 for FVC<80% predicted and OR 1.71, 95% CI 0.61 to 4.76 for FEV(1)/FVC<70% predicted using GOLD and NICE criteria. In addition, uneducated, currently smoking transit workers who had worked for more than 1 year, with three trips per day and more than 1 h transit time per trip were significantly associated with higher odds for respiratory function impairment at p<0.001, respectively.

CONCLUSIONS

Findings of this study lend weights to the existing literature on the adverse respiratory health effect of ambient air pollution on city transit workers globally. The role of other confounders acting synergistically to cause a more deleterious effect is obvious. In all, the effect depends on the mode and duration of exposure.

Non-sensitising air pollution at workplaces and adult-onset asthma in the beginning of this millennium

PURPOSE

This case-control study was undertaken to elucidate the controversy concerning whether low-level, long-term exposure to non-sensitising air pollution at workplaces may cause asthma.

METHODS

A case-control study of 192 adult-onset asthma cases aged 20-65 years and 323 controls was conducted in the southeast of Sweden. Cases were identified from computerised registers from the region, diagnosed 2000-2004 and diagnoses were confirmed via medical files. Referents were randomised from the population register of the region. Exposure was monitored by a 16-page questionnaire. Special attention was devoted to identifying and in the final analyses excluding subjects exposed to sensitising agents.

RESULTS

Three years or more of occupational exposure to air pollution from dust, smoke, fumes or vapours before the year of diagnosis by analyses adjusting for age yielded an increased risk for asthma (OR = 2.3, 95% CI 1.2-4.2) in men, while in women, no risk was seen. In a multiple logistic regression analysis in men without allergy in childhood, a significant risk was seen (OR = 2.8, 95% CI 1.07-7.4), when subjects exposed to identified allergens were excluded. In women, no excess risk was observed from occupational air pollution.

CONCLUSION

The results of this study support an association between occupational exposure to low level non-sensitising air pollution and adult-onset asthma in men.

Quantitative CT measures of emphysema and airway wall thickness are related to D(L)CO

There is limited knowledge on the relationship between diffusing capacity of the lung for carbon monoxide (D(L)CO) and quantitative computed tomography (CT) measures of emphysema and airway wall thickness.

STUDY QUESTION

What is the relationship between D(L)CO and the quantitative CT measures of emphysema and airway wall thickness in subjects with and without COPD?

METHODS

We included 288 COPD subjects (70% men) and 425 non-COPD subjects (54% men). All subjects were current or ex-smokers older than 40 years and all subjects underwent spirometry, diffusing capacity tests and CT examination. Quantitative CT measures included % low attenuation areas < -950 HU (%LAA) and standardized airway wall thickness (AWT-Pi10).

RESULTS

Multiple linear regression analyses showed significant associations between D(L)CO and both %LAA and AWT-Pi10 in the COPD group. The adjusted regression coefficients (SE) for D(L)CO (mmol min(-1) kPa(-1)) were -1.15 (0.11) per 10% increase in %LAA and 0.08 (0.03) per 0.1 mm increase in AWT-Pi10, and the models' adjusted R(2) was 0.65 and 0.49, respectively.

CONCLUSIONS

CT measured emphysema explains a large fraction of the variation of D(L)CO among COPD subjects, and more so in men. Airway wall thickness is also significantly associated with D(L)CO, but explains a much smaller fraction of the variation.

Asthma and health-related quality of life - effect of adjusting for potential confounders

BACKGROUND

Health-related quality of life (HRQoL) is an increasingly important outcome measure in medical research. We wanted to evaluate how adjustment for potential confounders affected the relationship between HRQoL and asthma. Furthermore, we wanted to evaluate the relationship of environmental tobacco smoke (ETS) with HRQoL.

METHODS

We carried out a cross-sectional Norwegian community study in 1996/1997 including 2306 randomly selected subjects aged 26 years-81 years. Data on HRQoL were measured by SF-12. The data were analyzed by robust linear regression analyses with the physical component score (PCS) and the mental component score (MCS) as dependent variables. The effect of adjusting for the potential confounders was analyzed by bootstrap confidence intervals for differences between the adjusted and unadjusted models.

RESULTS

The difference in the asthma coefficients between the unadjusted and adjusted models for both PCS and MCS varied from 0.1 to 1.1. The confidence intervals for these differences for PCS were (-0.3, 1.6) and (0.4, 1.8), using the definition 'asthma last 12 months' and 'physician's diagnosis of asthma', respectively. The confidence intervals for the corresponding differences for MCS were (-0.01, 1.3) and (-0.6, 0.4), respectively. Univariately, PCS was lower among subjects reporting ETS at home compared to people not reporting ETS at home, but this difference did not persist in the multivariate analyses. ETS at home was associated with slightly improved MCS.

CONCLUSION

Adjusting for potential confounders does not change the relationship between asthma and HRQoL overtly.

Desert dust exposure is associated with increased risk of asthma hospitalization in children

RATIONALE

Desert dust particles, including quartz, which causes inflammatory responses in the airway in animal studies, are transported to widespread regions around the globe. Epidemiologically, areas impacted by desert dust storms, such as communities in the Middle East and the Caribbean, seem to have higher incidences of asthma than might be expected.

OBJECTIVES

We investigated the magnitude of association between airborne mineral dust concentration and hospitalization of children for asthma exacerbation by using Light Detection And Ranging (LIDAR) with a polarization analyzer for an exposure measurement, which can distinguish mineral dust particles from other particles.

METHODS

A case-crossover design was used. The exposure measurement was LIDAR's nonspherical extinction coefficient. The outcome measurement was hospitalization of children aged 1 to 15 years for asthma exacerbation in eight principal hospitals in Toyama, a local area in Japan bordering the Japan Sea, during February to April, 2005 to 2009.

MEASUREMENTS AND MAIN RESULTS

During the study period, there were 620 admissions for asthma exacerbation, and 6 days with a heavy dust event (daily mineral dust concentration > 0.1 mg/m(3)). Conditional logistic regression showed a statistically significant association between asthma hospitalization and a heavy dust event. The crude odds ratio (OR) of the heavy dust event for hospitalization on the day was 1.88 (95% confidence interval [CI], 1.04-3.41; P = 0.037), and the OR of heavy dust event during the previous week was 1.83 (95% CI, 1.31-2.56; P = 0.00043). The OR adjusted by other air pollutant levels, pollen, and meteorological factors was 1.71 (95% CI, 1.18-2.48; P = 0.0050).

CONCLUSIONS

Heavy dust events are associated with an increased risk of hospitalizations for asthma.

Mechanism of asthmatic exacerbation by ambient air pollution particles

In the previous two to three decades, the prevalence of asthma has risen in numerous countries of the world. Correlating with this elevated prevalence of asthma, societies have observed increased air pollution from specific sources. Studies have implicated certain pollutants in asthmatic exacerbation. Particulate matter (PM) is the pollutant most frequently identified with worsening of this airway disease. PM is a temporally and spatially shifting suspension of solids and liquids originating from both natural and anthropogenic sources. Exposures to elevated levels of PM have been associated with asthmatic exacerbations by employing a diverse array of end points, including respiratory symptoms, use of medication, medical visits, emergency room visits, hospital admissions and pulmonary function decrements. Pertinent to worsening of asthma by ambient air PM, there are other particle-associated exposures that similarly precipitate asthmatic exacerbations. These include traffic-associated pollutants, diesel exhaust, emissions from gas and wood stoves, burning of biomass and environmental tobacco smoke. It is widely accepted that the biological effects exerted by all particle exposures result from oxidative stress. This stimulates cell signaling, transcription factor activation and mediator release in the respiratory tract, culminating in inflammation. Other postulated mechanisms for asthmatic exacerbation following PM exposure include an impact on the incidence of infections and adjuvant effects.

Poverty-associated risk factors for wheezing in the first year of life in Honduras and El Salvador

BACKGROUND

Risk factors for wheezing specifically during the first year of life have been studied in well-developed countries, but the information from developing countries is very scarce. There are no such studies focusing on factors derived from poverty. The aim of the present study was to determine if risk factors related to poverty are associated to wheezing during the first year of life in infants from Honduras and El Salvador.

METHODS

A survey, using a validated questionnaire, was carried out in the metropolitan area of San Pedro Sula (Honduras) and in La Libertad (El Salvador) in centres where infants attended for a scheduled vaccination shot or a healthy child visit at 12 months of age. Fieldworkers offered questionnaires to parents and helped the illiterate when necessary. The main outcome variable was wheezing during the first year of life, as reported by parents.

RESULTS

A total of 1047 infants in El Salvador and 780 in Honduras were included in the analysis. The prevalence of wheeze in the first year was higher in El Salvador (41.2%) than in Honduras (27.7%), as was recurrent wheezing defined as three or more episodes (18.4% vs. 11.7%). Wheezing and recurrent wheezing was associated to unpaved floor in the household (summary odds ratios for both countries 1.55, p=0.036 and 1.72, p=0.054 for any wheeze and recurrent wheezing, respectively); dust entering from streets (1.30, p=0.052 and 1.67, p=0.008); living in a heavily polluted area (1.33, p=0.037 and 1.52, p=0.033); and having mould stains on the household walls (1.36, p=0.072 and 1.76, p=0.007). Furthermore, marginal associations were found for additional person at home and use of kerosene as cooking fuel. University studies in the mother (0.34, p=0.046 and 0.32, p=0.022) and a professional occupation in the father (0.34, p=0.046 and 0.26, p=0.047) were associated to a lower risk.

CONCLUSIONS

The prevalence of wheezing and recurrent wheezing is notoriously high in El Salvador and Honduras. In those populations factors related to poverty are associated to a higher prevalence of wheezing and recurrent wheezing, whereas higher maternal education and paternal professional occupation behave as protective factors.

Association between respiratory symptom score and 30-year cause-specific mortality and lung cancer incidence

INTRODUCTION

Respiratory symptoms are among the main reasons why patients make contact with healthcare professionals and they are associated with several diseases.

OBJECTIVE

The aim of this study was to investigate the relationship between respiratory symptoms reported at one time and 30 years cause-specific mortality and incidence of lung cancer in an urban Norwegian population.

MATERIALS AND METHODS

A total of 19 998 men and women, aged 15-70 years, were in 1972 selected from the general population of Oslo. They received a postal respiratory questionnaire (response rate 89%). All were followed for 30 years for end-point mortality and for lung cancer. The association between respiratory symptoms, given as a symptom load, and end point of interest were investigated separately for men and women by multivariable analyses, with adjustment for age, occupational exposure to air pollution and smoking habits.

RESULTS

A total of 6710 individuals died during follow-up. Obstructive lung diseases (OLDs) and pneumonia accounted for 250 and 293 of the total deaths, respectively. Ischaemic heart disease (IHD) accounted for 1572; stroke accounted for 653 of all deaths. Lung cancer developed in 352 persons during follow-up. The adjusted hazard ratio for mortality from OLD and pneumonia, IHD and stroke increased in a dose-response manner with symptom score, more strongly for OLD and IHD than for pneumonia and stroke.

CONCLUSIONS

Respiratory symptoms were positively associated with mortality from OLD, pneumonia, IHD and stroke, and incidence of lung cancer. This association was significant for mortality from OLD and IHD.

Attributable fractions for partitioning risk and evaluating disease prevention: a practical guide

INTRODUCTION

The attributable fraction (AF) is used for quantifying the fraction of diseased ascribable to one or more exposures. The methodology and software for its estimation has undergone a considerable development during the last decades.

OBJECTIVES

To introduce methods for: (i) apportioning excess risk to multiple exposures, groups of exposures and subpopulations; (ii) graphical description; and (iii) survival data.

RESULTS

Adjusted, sequential and average AFs are reasonable measures obtainable with standard software. The latter two both sum up to the combined AF for a set of exposures. The average AFs are independent of the exposures' ordering. For an ordered, preventive strategy, scaled sample space cubes illustrate the effects on the risk of disease from stepwise exposure removal. Pie charts illustrate the portions of the total risk ascribed to different exposures or risk-profiles. Attributable hazard fraction, AF before time t, and AF within study incorporate time to disease and interventions.

CONCLUSIONS

The practice of crude calculations of AFs in epidemiology should be abandoned. Further development of methods for AFs with survival data and possibly linking it to causal modelling is of interest.

Prevalence of temporary social security benefits due to respiratory disease in Brazil

OBJECTIVE

To determine the prevalence of temporary social security benefits due to respiratory disease granted to employees, as well as the number of lost workdays and costs resulting from those in Brazil between 2003 and 2004.

METHODS

Cross-sectional study using data obtained from the Unified System of Benefits of the Brazilian Institute of Social Security (INSS, Instituto Nacional de Seguro Social) and the Brazilian Social Registry Database. Data regarding gender, age, diagnosis and type of economic activity, as well as type, duration and cost of benefits, were compiled.

RESULTS

Respiratory diseases accounted for 1.3% of the total number of temporary social security benefits granted by INSS, with a prevalence rate of 9.92 (per 10,000 employment contracts). Females and individuals older than 50 years of age were the most affected. Non-work-related benefits were more common than were work-related benefits. The most prevalent diseases were pneumonia, asthma and COPD, followed by laryngeal and vocal cord diseases. The most prevalent types of economic activity were auxiliary transportation equipment manufacturing, tobacco product manufacturing and computer-related activities. The mean duration of benefits was 209.68 days, with a mean cost of R$ 4,495.30 per occurrence. Respiratory diseases caused by exogenous agents demanded longer sick leave (mean, 296.72 days) and greater cost (mean, R$ 7,105.74).

CONCLUSIONS

The most prevalent diseases were airway diseases and pneumonia. Workers from auxiliary transportation equipment manufacturing, tobacco product manufacturing and computer-related activities were the most affected. Diseases caused by exogenous agents demanded longer sick leaves and resulted in greater costs.

Effect of occupation and smoking on respiratory symptoms in working children

OBJECTIVES

To compare the respiratory symptoms and the lung function of children who work in different occupational groups.

METHODS

The study was performed among children attending vocational training centers. The participants were evaluated in six different occupation groups. Chronic cough, wheezing and shortness of breath were evaluated by questionnaire. The association of independent variables with the respiratory symptoms was investigated through both univariate and multivariate methods.

RESULTS

Among 642 children, 534 were males; the mean age was 17.7 +/- 1.0 years. Using an internal reference group, the odds ratios of chronic cough were significantly higher in the lathe (OR: 2.0, 95%CI: 1.07-3.74), coiffure (OR: 1.94. 95%CI: 1.01-3.70), and electricity-construction (OR: 2.63, 95%CI: 1.06-6.54) groups after adjustment for smoking, age, gender, and work characteristics. There were no significant differences in spirometric values between occupational groups in either smoking or non-smoking males. In non-smoking females, median values of FEV(1) (P: 0.046), PEF (P: 0.005) and FEF(25-75%) (P: 0.019) were lower in the textile compared to the coiffure group. There was no significant association between the total working time and spirometric values. There was no statistically significant relationship between the work-related factors and the smoking status.

CONCLUSIONS

The prevalence of chronic cough was higher in the lathe, coiffure, and electricity-construction groups and pulmonary function tests were lower in the non-smoking textile female group. Working children should be screened for respiratory symptoms and disease.

Asthma caused by occupational exposures is common - a systematic analysis of estimates of the population-attributable fraction

Background

The aim of this paper is to highlight emerging data on occupational attributable risk in asthma. Despite well documented outbreaks of disease and the recognition of numerous specific causal agents, occupational exposures previously had been relegated a fairly minor role relative to other causes of adult onset asthma. In recent years there has been a growing recognition of the potential importance of asthma induced by work-related exposures

Methods

We searched Pub Med from June 1999 through December 2007. We identified six longitudinal general population-based studies; three case-control studies and eight cross-sectional analyses from seven general population-based samples. For an integrated analysis we added ten estimates prior to 1999 included in a previous review.

Results

The longitudinal studies indicate that 16.3% of all adult-onset asthma is caused by occupational exposures. In an overall synthesis of all included studies the overall median PAR value was 17.6%.

Conclusion

Clinicians should consider the occupational history when evaluating patients in working age who have asthma. At a societal level, these findings underscore the need for further preventive action to reduce the occupational exposures to asthma-causing agents.

Asthma and allergy: short texts and recommendations of the expert conference of the French Speaking Pneumology Society (SPLF), in partnership with the French Society of Allergology and Clinical Immunology (SFAIC), the French Society of Occupational Medicine (SFMT) and the "Asthma-Allergy" association

The Asthma Plan published by the French Health Ministry in 2002, the experts conferences edited by ANAES on therapeutic education and follow-up of asthma, the inclusion of this disease in the Public Health Law have been remarkable steps in France during the last few years. The medical community, more particularly the pneumological community, has shown its commitment in the treatment of this public health problem. But allergy was not sufficiently taken into account, although it is responsible for nearly 50 to 60% cases of asthma. In most so-called developed countries the prevalence of asthma and of allergies has increased in the last twenty years. Its progress varies according to country and age group: the increased prevalence of allergy, more specifically of rhinitis and eczema, is most marked in children aged 6-7 year. The prevalence of asthma seems to have reached a plateau in certain northern countries or seems to have decreased in 13-14 year olds (Anglo-Saxon countries). There were multiple reasons, generally attributed to changes in life-style. Asthma is the result of an interaction between a genetic predisposition and the environment, where allergens are present, but also smoking. The relationships between allergy and asthma are complex. This conference discussed the various essential issues that face doctors who treat patients with asthma in their daily practice. The risk factors, the methods of exploration in children and adults and the specific treatments are, indeed, essential issues to be evaluated in a frequent pathology that interests a large number of physicians. The variety of experts is wide, representing pneumology (French Speaking Pneumology Society), the occupational medicine world (French Society of Occupational Medicine), the allergic pathology (French Society of Allergology and Clinical Immunology), and patients with the patient association "Asthma & Allergy", physicians belonging to the general medicine community, general hospitals, private hospitals and academic hospitals in France. The proposed guidelines are aimed at helping practitioners in distinguishing what is established from what remains to be demonstrated and/or assessed with respect to the different modalities for the exploration or treatment of allergic asthma.

Environmental factors and allergic disorders

Despite numerous studies on possible associations between environmental exposure and allergic disorders, any conclusions made remain a matter of controversy. We conducted a review of evidence in relation to environmental and nutritional determinants and wheeze, asthma, atopic dermatitis, and allergic rhinitis. Identified were 263 articles for analysis after consideration of 1093 papers that were published since 2000 and selected by electronic search of the PubMed database using keywords relevant to epidemiological studies. Most were cross-sectional and case-control studies. Several prospective cohort studies revealed inconsistent associations between various environmental factors and the risk of any allergic disorder. Therefore, the evidence was inadequate to infer the presence or absence of a causal relationship between various environmental exposures and allergic diseases. However, evidence is suggestive of positive associations of allergies with heredity. Because almost all the studies were performed in Western countries, the application of these findings to people in other countries, including Japan, may not be appropriate. Further epidemiological information gained from population-based prospective cohort studies, in particular among Japanese together with other Asians, is needed to assess causal relationships between various environmental factors and allergic diseases.

[Epidemiology and etiologic agents of occupational asthma]

INTRODUCTION

Occupational asthma is, by definition, a disease that can be prevented through appropriate protective strategies. Epidemiological information is required to guide these interventions, and we here examine epidemiological data on the burden, causes, and risk factors for this condition.

STATE OF THE ART

Population-based surveys indicate that approximately 15% of adult asthma is attributable to the workplace environment. The most common occupational agents implicated include flour, isocyanates, latex, and persulphate salts. The occupations in which occupational asthma has been most commonly reported are bakers, spray painters, health-care workers, hairdressers, and cleaners. The level of exposure to sensitizing agents seems to be the most relevant risk factor. Atopy is a significant risk factor only for the development of sensitization to high molecular weight agents. The role of other individual determinants, such as genetic factors, has been less consistently established. Occupational asthma is associated with a substantial adverse impact on the employment and financial status of affected workers.

PERSPECTIVES

Methodological improvements are required in order to distinguish more accurately between occupational and work-exacerbated asthma. Further investigations of the effectiveness of primary and secondary preventive interventions are also needed.

Feasible and simple exclusion criteria for pulmonary reference populations

BACKGROUND

International guidelines recommend that pulmonary reference populations consist of never-smokers without respiratory diseases or symptoms, but the diseases and symptoms are not clearly specified. The present study aimed to identify simple exclusion criteria for defining pulmonary reference populations.

METHODS

Based on a random sample from a general population (the parent population), 2,358 subjects aged 26-82 years performed spirometric tests. From this sample, subjects were stepwise excluded according to self-reported obstructive lung diseases, symptoms and smoking history. Four increasingly more healthy respiratory reference populations were formed. Prediction equations for the median and lower limit of normal lung function were derived using quantile regression analysis.

RESULTS

Subjects without self-reported obstructive lung diseases or the cardinal respiratory symptoms of breathlessness, cough or wheeze (population B), never-smokers without cardinal symptoms (population C) and never-smokers without any respiratory symptoms (population D) constituted 50% (n = 1,184), 23% (n = 539) and 14% (n = 331) of the parent population (population A), respectively. The largest discrepancy between prediction equations was found between the parent population and the population without cardinal respiratory symptoms (population B) (p<0.05). Minor changes in the reference equations were also seen when excluding ever-smokers (population C). There was no additional change with exclusion of other respiratory symptoms (population D). Age-related decline in lung function was steepest in the parent population.

CONCLUSIONS

Obstructive lung diseases, smoking history, breathlessness, cough and wheeze are optimal exclusion criteria for a pulmonary reference population. Further validation of the exclusion criteria identified in this study is recommended with identical wording in other and larger multinational populations.

Occupational asthma in New South Wales (NSW): a population-based study

BACKGROUND

The proportion of asthma in adults that is due to occupational exposures is not known.

AIM

To examine the contribution of workplace exposures to the development of asthma in adults in New South Wales (NSW) in a cross sectional, population-based study.

METHODS

A randomly selected population of 5,331 18- to 49-year olds completed and returned a mailed questionnaire (response rate 37%). In adult-onset asthmatics we examined the association of asthma with reported exposure, within 1 year of asthma onset, to a list of occupations and exposures known to be at risk for occupational asthma (high-risk jobs and exposures).

RESULTS

Among 910 subjects (18%) with asthma, 383 (7%) subjects reported adult-onset disease. After adjusting for sex, age and smoking, working in any high-risk job or exposure at the time of asthma onset was significantly associated with adult-onset asthma (OR 1.51, 95% CI 1.19-1.92). The population attributable risk (PAR) of adult-onset asthma for either a high-risk job or an exposure was 9.5%. Sudden onset, irritant or reactive airways dysfunction syndrome type exposures were associated with adult-onset asthma (OR 4.65, 95% CI 1.64-13.2). The PAR of adult-onset asthma for these exposures was 0.2%.

CONCLUSION

Reported adult onset of asthma is common and occupational exposures may be associated with 9.5% of prevalent cases of adult-onset asthma in NSW.

Exposure to environmental tobacco smoke in a general population

AIMS

To estimate how the level of exposure to environmental tobacco smoke (ETS) in pregnancy, childhood and adulthood vary with personal characteristics in a general population.

METHODS

In 1996/1997, a community sample of 3181 adults, aged 26-82, received a mailed questionnaire, to which 2819 subjects responded. The prevalences of ETS exposure were estimated according to sex, age, educational level, smoking, occupational dust or gas exposure and exposure to moulds. Logistic regression was used to estimate the adjusted odds ratios for the different ETS exposures with respect to these covariates.

RESULTS

Altogether 9% reported exposure to maternal smoking in foetal life and 23% in childhood. Fourteen percent reported current domestic ETS exposure, while 13% reported current occupational ETS. Occupational ETS exposure was more frequent among men (16%) than women (10%). The oldest subjects (61-82 years) reported less ETS exposures than the younger subjects. Current smokers and subjects with occupational dust or fumes exposure had a higher prevalence for all the ETS exposures compared to ex- and never smokers and subjects without occupational exposure, respectively.

CONCLUSION

From a general population sample male sex, younger age, current smoking, and occupational dust or fumes exposure were associated with higher level of ETS exposure.

Persistence of respiratory symptoms in ex-underground iron ore miners

AIMS

To assess the persistence of respiratory symptoms in ex-miners after cessation of mining exposure.

METHODS

Population-based cross-sectional study using a postal questionnaire comparing prevalence of symptoms between ex-miners who had stopped mining at least 1 year before the study and referents not occupationally exposed to irritants or dust. Age, smoking and a family history of asthma were considered as possible confounders in the analysis.

RESULTS

A total of 206 ex-miners and 4,560 referents participated. Ex-miners had on average been working as miners for 13 years and had stopped mining 16 years before the study. Chronic productive cough and physician-diagnosed chronic bronchitis were significantly more common among ex-miners (P < 0.05 and <0.01, respectively). Furthermore, there was a trend that other respiratory symptoms were more common in ex-miners.

CONCLUSION

Ex-miners had an increased risk of chronic productive cough and physician-diagnosed chronic bronchitis many years after they had stopped working as a miner.

Respiratory symptoms as predictors of all-cause mortality in an urban community: a 30-year follow-up

OBJECTIVE

We investigated the relationship between respiratory symptoms and mortality from all causes in a large Norwegian population. We also examined mortality during separate periods of follow-up.

DESIGN

Population-based, prospective cohort study.

SETTING AND SUBJECTS

A total of 19,998 men and women were randomly selected from the general population of Oslo. They received a postal respiratory questionnaire. The response rate was 88%.

MAIN OUTCOME MEASURES

The relationship between 11 respiratory symptoms and 30 years of total mortality was investigated separately for men and women by multivariate analyses with adjustment for age, smoking habits and occupational exposure to air pollution.

RESULTS

The relative mortality risk in comparison with asymptomatic subjects varied from 1.36 (95% confidence interval 1.25-1.48) for cough symptoms to 2.46 (2.13-2.85) for severe dyspnoea amongst men; the corresponding rates amongst women were 1.28 (1.16-1.40) and 1.52 (1.31-1.75), respectively. The relative risk of mortality in individuals with 1-3, 4-6 and 7 or more symptoms was 1.20, 1.60 and 2.53 (P for trend 0.000) in men and 1.14, 1.47 and 1.84 (P for trend 0.000) in women. Except for cough, the mortality rates associated with respiratory symptoms decreased significantly during follow-up. The positive association between respiratory symptoms and mortality was observed in people with and without cardiopulmonary diseases.

CONCLUSIONS

Respiratory symptoms were significant predictors of mortality from all causes over 30 years, decreased during follow-up and were still increased after 30 years.

Post-bronchodilator spirometry reference values in adults and implications for disease management

RATIONALE

International guidelines promote the use of post-bronchodilator spirometry values in the definition and severity classification of chronic obstructive pulmonary disease. However, post-bronchodilator reference values have not yet been developed.

OBJECTIVES

To derive reference values for post-bronchodilator forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC, and to compare these reference values with locally derived and existing pre-bronchodilator reference values.

METHODS

Based on a random sample of a general adult population, 2,235 subjects (70% of invited subjects) performed spirometry with reversibility testing. A reference population of healthy never-smokers constituted 23% of the study population (n=515). Reference values for median and lower-limit-of-normal pre- and post-bronchodilator lung function and bronchodilator response were modeled using quantile regression analyses.

MAIN RESULTS

The reference population had equal proportions of men and women in the age range 26-82 yr. Both FEV1 and FVC decreased with age and increased with height. FEV1/FVC decreased with age, although this trend was not statistically significant for men after bronchodilatation. Linear models gave the best overall fit. Lower-limit-of-normal post-bronchodilator FEV1/FVC exceeded 0.7 for both sexes. Post-bronchodilator prediction equations gave higher predicted FEV1 and FEV1/FVC than both locally derived and existing pre-bronchodilator equations. The bronchodilator response decreased with age.

CONCLUSIONS

The present study is the first to develop reference values for post-bronchodilator lung function. Post-bronchodilator prediction equations can facilitate better management of patients with chronic obstructive pulmonary disease by avoiding falsely high FEV1% predicted with a subsequent underestimation of disease severity.