Studies have documented high rates of asthma symptoms among responders to the World Trade Center (WTC) disaster. However, whether there are increased rates of asthma among responders compared to the general population is unknown.
The study population consisted of a prospective cohort of 20,834 responders participating in the WTC Medical Monitoring and Treatment Program between July 2002 and December 2007. We calculated prevalence and standardized morbidity ratios (SMRs) of lifetime asthma and 12-month asthma (defined as ≥1 attacks in the prior 12 months) among WTC responders. The comparison population consisted of >200,000 adults who completed the National Health Interview Survey in 2000 (for pre-9/11 comparisons) and between 2002 and 2007 (for post-9/11 comparisons).
WTC responders were on average 43 ± 9 years old, 86% male, 59% white, and 42% had an occupation in protective services. The lifetime prevalence of asthma in the general population was relatively constant at about 10% from 2000 to 2007. However, among WTC responders, lifetime prevalence increased from 3% in 2000, to 13% in 2002, and 19% in 2007. The age-adjusted overall SMR for lifetime asthma among WTC responders was 1.8 (95% CI: 1.8-1.9) for men and 2.0 (95% CI: 1.9-2.1) for women. Twelve-month asthma was also more frequent among WTC responders compared to the general population (SMR 2.4, 95% CI: 2.2-2.5) for men and 2.2 (95% CI: 2.0-2.5) for women.
WTC responders are at an increased risk of asthma as measured by lifetime prevalence or active disease.
[Show abstract][Hide abstract] ABSTRACT: Exposures at work are an often overlooked but important cause of asthma and other airway diseases. Evidence from large pop-ulation-based studies shows that 1 in 10 cases of asthma occurring, recurring, or worsening in adulthood can be related to occupational factors. The majority of cases are of pre-existing asthma made worse by employment [work-exacerbated asthma (WEA)]. Adults presenting with increased or new asthma symptoms should be carefully assessed so that WEA can be distinguished from true occupational asthma (OA), a disease that is directly caused by a workplace exposure. Airways disease may also arise from toxic exposures to respiratory irritants at work. In most cases, symptoms are self-limiting, but an asthma-like syndrome (irritant-induced asthma) occasionally results. OA and WEA require different diagnostic and management approaches. Key steps required to make a definitive diagnosis of either condition are an awareness of the disease with an associated low threshold of suspicion, time spent acquiring a full and detailed job history followed by care-fully considered application of a few simple important diagnostic investigations. A satisfying part of managing OA is the opportunity for cure (provided that the necessary management advice can be imple-mented), although the socioeconomic consequences—mainly to the patient themselves—can be high. PREVALENCE Asthma is common in the working age population, affecting 300 million adults worldwide 1 ; large epidemiological studies have found that about 1 in 10 cases of asthma are attributable to occupation. 2,3 This figure will appear surpris-ingly high to most general respiratory physicians; the dis-crepancy between population surveys and clinical practice is because of a number of factors, including low consultation rates of symptomatic patients because of lack of recognition of the work relationship of their symptoms, high level of acceptance of chronic symptoms, and fears surrounding loss of employment. In addition, health care professionals often omit to make specific inquiries regarding work relationship of asthma symptoms and are unlikely to be aware of all occu-pations at increased risk of occupational asthma (OA). A UK study carried out in general practice with 9000 registered pa-tients, found 346 adults of working age with asthma. 4 Almost half had adult onset disease and a third of these worked in a job with a high risk of OA. Only 7 (4%) were recognized to have OA. 4 Patients can present at any time during working life, commonly but not exclusively within the first two years of starting new employment or a change in exposure. Estimates of the prevalence—and less frequently incidence—of OA are available for both occupational and community populations. Most workplace-based studies use standard cross-sectional epidemiological methods; occasion-ally longitudinal (cohort) designs, most of them prospective, are used. A "healthy worker effect" (reflecting selection into and survival within a workforce) that underestimates frequency is likely to occur with cross-sectional approaches. Despite these limitations, workplace-based estimates of disease frequency have provided much of our knowledge of the detailed epidemiology of OA. Several countries have established surveillance schemes for OA. These measure disease reported by specialized physicians, usually in occupational or respiratory medical practice; some schemes are linked to compensation claims. Where workforce denominators are available, occupation-specific incidence rates may be estimated, although these are often crude and probably underestimate the true incidence. 5 These data can demonstrate temporal or geographical changes in disease incidence in specific industries or agents but findings are limited by small numerators because of under-reporting and international variations in diagnostic procedures. National level data especially relative frequencies of disease by industry have helped to influence state regulation.
[Show abstract][Hide abstract] ABSTRACT: First responders (FRs) present at Ground Zero within the critical first 72 h after the World Trade Center (WTC) collapse have progressively exhibited significant respiratory injury. The majority (>96%) of WTC dusts were >10 μm and no studies have examined potential health effects of this size fraction. This study sought to develop a system to generate and deliver supercoarse (10-53 μm) WTC particles to a rat model in a manner that mimicked FR exposure scenarios. A modified Fishing Line generator was integrated onto an intratracheal inhalation (ITIH) system that allowed for a bypassing of the nasal passages so as to mimic FR exposures. Dust concentrations were measured gravimetrically; particle size distribution was measured via elutriation. Results indicate that the system could produce dusts with 23 μm mass median aerodynamic diameter (MMAD) at levels up to ≥1200 mg/m(3). To validate system utility, F344 rats were exposed for 2 h to ≈100 mg WTC dust/m(3). Exposed rats had significantly increased lung weight and levels of select tracer metals 1 h after exposure. Using this system, it is now possible to conduct relevant inhalation exposures to determine adverse WTC dusts impacts on the respiratory system. Furthermore, this novel integrated Fishing Line-ITIH system could potentially be used in the analyses of a wide spectrum of other dusts/pollutants of sizes previously untested or delivered to the lungs in ways that did not reflect realistic exposure scenarios.Journal of Exposure Science and Environmental Epidemiology advance online publication, 13 November 2013; doi:10.1038/jes.2013.68.
Journal of Exposure Science and Environmental Epidemiology 11/2013; 24(1). DOI:10.1038/jes.2013.68 · 3.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To identify the similarities and differences between nonwork-related adult-onset and occupational asthma from various literature sources published between 2010 and 2013, with respect to the epidemiology, phenotypic manifestations, and risk factors for the disease.
The incidence of adult-onset asthma from pooled population studies is estimated to be 3.6 per 1000 person-years in men and 4.6 cases per 1000 person-years in women. In adults with new-onset asthma, occupational asthma is a common asthma phenotype. Work-related factors are estimated to account for up to 25% of adult cases of asthma and occupational asthma comprising about 16% of adult-onset asthma cases. The review finds that nonwork-related adult-onset asthma is a heterogenous entity and that environmental exposure factors (aside from occupational exposures) appear to have a lesser role than host factors when compared with occupational asthma.
Large-scale general population studies are needed to identify the similarities and differences between nonwork-related adult-onset and occupational asthma, which may enable a better understanding of these entities and promote efforts towards holistic management approaches for these asthma phenotypes.
Current Opinion in Allergy and Clinical Immunology 02/2014; 14(2). DOI:10.1097/ACI.0000000000000042 · 3.57 Impact Factor
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