Gillian Earnest

The occupational burden of chronic obstructive pulmonary disease

Although chronic obstructive pulmonary disease (COPD) is attributed predominantly to tobacco smoke, occupational exposures are also suspected risk factors for COPD. Estimating the proportion of COPD attributable to occupation is thus an important public health need. A randomly selected sample of 2,061 US residents aged 55–75 yrs completed telephone interviews covering respiratory health, general health status and occupational history. Occupational exposure during the longest-held job was determined by self-reported exposure to vapours, gas, dust or fumes and through a job exposure matrix. COPD was defined by self-reported physicians diagnosis. After adjusting for smoking status and demography, the odds ratio for COPD related to self-reported occupational exposure was 2.0 (95% confidence interval (CI) 1.6–2.5), resulting in an adjusted population attributable risk (PAR) of 20% (95% CI 13–27%). The adjusted odds ratio based on the job exposure matrix was 1.6 (95% CI 1.1–2.5) for high and 1.4 (95% CI 1.1–1.9) for intermediate probability of occupational dust exposure; the associated PAR was 9% (95% CI 3–15%). A narrower definition of COPD, excluding chronic bronchitis, was associated with a PAR based on reported occupational exposure of 31% (95% CI 19–41%). Past occupational exposures significantly increased the likelihood of chronic obstructive pulmonary disease, independent of the effects of smoking. Given that one in five cases of chronic obstructive pulmonary disease may be attributable to occupational exposures, clinicians and health policy-makers should address this potential avenue of chronic obstructive pulmonary disease causation and its prevention.

The work impact of asthma and rhinitis: Findings from a population-based survey

Asthma and rhinitis are common chronic conditions that affect adults of working age. Little is known about their relative impacts on work loss and decreased productivity. Using random digit telephone dialing, we carried out a population-survey of adults in Northern California aged 18-50 years. We interviewed 125 persons with asthma (with or without concomitant rhinitis) and 175 persons with rhinitis alone. Study eligibility was based on subject report of a physicians diagnosis of asthma and/or a rhinitis-related condition. Any adult labor force participation since condition onset was lower among those with asthma (88%) than among those with rhinitis alone (97%) (P = 0.002). In contrast, among those still employed, decreased job effectiveness was more frequently reported in the rhinitis group (43 of 121; 36%) compared to those with asthma (14 of 72; 19%) (P = 0.02). Condition-attributed lost work was common in both groups, with more than 20% reporting one or more complete or partial work days lost in the 4 weeks previous to interview. Taking into account age, gender, race, and smoking status, those with asthma were more likely to have no labor force participation after diagnosis (OR = 3.0; 95% CI 1.1-7.7) and less likely to report decreased job effectiveness among those remaining employed (OR = 0.4; 95% CI 0.2-0.9). Excluding subjects from the rhinitis group most likely to have unreported asthma based on past medication use had little impact on these associations. Both asthma and rhinitis negatively affect work productivity. Those with asthma are less likely to be employed at all, while among those remaining on the job, rhinitis is a more potent cause of decreased work effectiveness. The economic impact of asthma and rhinitis and related conditions may be under-appreciated.

Occupational exposures and the risk of COPD: dusty trades revisited

Background: The contribution of occupational exposures to chronic obstructive pulmonary disease (COPD) and, in particular, their potential interaction with cigarette smoking remains underappreciated. Methods: Data from the FLOW study of 1202 subjects with COPD (of which 742 had disease classified as stage II or above by Global Obstructive Lung Disease (GOLD) criteria) and 302 referent subjects matched by age, sex and race recruited from a large managed care organisation were analysed. Occupational exposures were assessed using two methods: self-reported exposure to vapours, gas, dust or fumes on the longest held job (VGDF) and a job exposure matrix (JEM) for probability of exposure based on occupation. Multivariate analysis was used to control for age, sex, race and smoking history. The odds ratio (OR) and adjusted population attributable fraction (PAF) associated with occupational exposure were calculated. Results: VGDF exposure was associated with an increased risk of COPD (OR 2.11; 95% CI 1.59 to 2.82) and a PAF of 31% (95% CI 22% to 39%). The risk associated with high probability of workplace exposure by JEM was similar (OR 2.27; 95% CI 1.46 to 3.52), although the PAF was lower (13%; 95% CI 8% to 18%). These estimates were not substantively different when the analysis was limited to COPD GOLD stage II or above. Joint exposure to both smoking and occupational factors markedly increased the risk of COPD (OR 14.1; 95% CI 9.33 to 21.2). Conclusions: Workplace exposures are strongly associated with an increased risk of COPD. On a population level, prevention of both smoking and occupational exposure, and especially both together, is needed to prevent the global burden of disease.

Exposure to indoor combustion and adult asthma outcomes: environmental tobacco smoke, gas stoves, and woodsmoke.

Background: Because they have chronic airway inflammation, adults with asthma may be particularly susceptible to indoor air pollution. Despite widespread exposure to environmental tobacco smoke (ETS), gas stoves, and woodsmoke, the impact of these exposures on adult asthma has not been well characterised. Methods: Data were used from a prospective cohort study of 349 adults with asthma who underwent structured telephone interviews at baseline and 18 month follow up. The prospective impact of ETS, gas stove, and woodsmoke exposure on health outcomes was examined. Results: ETS exposure at baseline interview was associated with impaired health status at longitudinal follow up. Compared with respondents with no baseline self-reported exposure to ETS, higher level exposure (≥7 hours/week) was associated with worse severity of asthma scores at follow up, controlling for baseline asthma severity, age, sex, race, income, and educational attainment (mean score increment 1.5 points; 95% CI 0.4 to 2.6). Higher level baseline exposure to ETS was also related to poorer physical health status (mean decrement –4.9 points; 95% CI –8.4 to –1.3) and asthma specific quality of life (mean increase 4.4 points; 95% CI –0.2 to 9.0) at longitudinal follow up. Higher level baseline ETS exposure was associated with a greater risk of emergency department visits (OR 3.4; 95% CI 1.1 to 10.3) and hospital admissions for asthma at prospective follow up (OR 12.2; 95% CI 1.5 to 102). There was no clear relationship between gas stove use or woodstove exposure and asthma health outcomes. Conclusion: Although gas stove and woodstove exposure do not appear negatively to affect adults with asthma, ETS is associated with a clear impairment in health status.

Area-level socio-economic status and health status among adults with asthma and rhinitis

Socio-economic status (SES) may affect health status in airway disease at the individual and area level. In a cohort of adults with asthma, rhinitis or both conditions, questionnaire-derived individual-level SES and principal components analysis (PCA) of census data for area-level SES factors were used. Regression analysis was utilised to study the associations among individual- and area-level SES for the following four health status measures: severity of asthma scores and the Short Form-12 Physical Component Scale (SF-12 PCS) (n = 404); asthma-specific quality of life (QoL) scores (n = 340); and forced expiratory volume in one second (FEV1) per cent predicted (n = 218). PCA yielded a two-factor solution for area-level SES. Factor 1 (lower area-level SES) was significantly associated with poorer SF-12 PCS and worse asthma QoL. These associations remained significant after adding individual-level SES. Factor 1 was also significantly associated with severity of asthma scores, but not after addition of the individual-level SES. Factor 2 (suburban area-level SES) was associated with lower FEV1 per cent predicted in combined area-level and individual SES models. In conclusion, area-level socio-economic status is linked to some, but not all, of the studied health status measures after taking into account individual-level socio-economic status.

Work life of persons with asthma, rhinitis, and COPD: A study using a national, population-based sample

ObjectiveTo estimate the duration of work life among persons reporting a physicians diagnosis of COPD, asthma, or rhinitis compared to those with select non-respiratory conditions or none and to delineate the factors associated with continuance of employment.MethodsPersons ages 55 to 75 reporting a physicians diagnosis of COPD, asthma, or rhinitis as well as those without any of these conditions were identified by random-digit dialing (RDD) in the continental U.S and administered a structured survey. We used Kaplan-Meier life table analysis to estimate the duration of work life among persons with and without the three conditions and Cox proportional hazard regression to examine the role of demographic and work characteristics in the proportion leaving employment in each time interval.ResultsPersons with COPD, asthma, and rhinitis were no less likely than the remainder of the population to have ever worked, but those with COPD were less likely to be working when interviewed or as of age 65, whichever came first. As of age 55, only 62 percent of persons with COPD continued to work versus 72 and 78 percent of persons with asthma and rhinitis, respectively. Persons with COPD, asthma, and rhinitis all had an elevated risk of leaving work prior to age 65 relative to those without chronic conditions, with and without adjustment for demographic and work characteristics.ConclusionCOPD and to a lesser extent asthma and rhinitis were associated with a substantially shortened work life, an effect not due to demographic and work characteristics.

Impact of the home indoor environment on adult asthma and rhinitis

Objective: We sought to study the combined effects of multiple home indoor environmental exposures in adult asthma and rhinitis. Methods: We studied 226 adults with asthma and rhinitis by structured interviews and home assessments. Environmental factors included dust allergen, endotoxin and glucan concentrations, and indoor air quality (IAQ) variables. Outcomes included forced expiratory volume in 1 second (FEV1) percent predicted, Severity of Asthma Score (SAS), Short-Form (SF)-12 Physical Component Scale (PCS), and asthma Quality of Life (QOL) score. Results: House dust-associated exposures together with limited IAQ variables were related to FEV1 % predicted (R2 = 0.24; P = 0.0001) and SAS (R2 = 0.18; P = 0.007). IAQ and limited dust variables were associated with SF-12 PCS (R2 = 0.15; P = 0.02), but not QOL (R2 = 0.13; P = 0.16). Conclusions: The home environment is strongly linked to lung function, health status, and disease severity in adult asthma and rhinitis.

Further Exploration of the Links between Occupational Exposure and Chronic Obstructive Pulmonary Disease

Objective: To examine occupational risk for Chronic Obstructive Pulmonary Disease (COPD). Methods: We randomly recruited 233 subjects aged 55 to 75 reporting a physician’s diagnosis of COPD, emphysema, or chronic bronchitis. Interviews assessed cigarette smoking and longest held job, identifying exposure to vapors, gas, dust, or fumes (VGDF). Lung function was assessed in n = 138. Comparison data were derived from a sample of referents without COPD. Results: VGDF was reported in 123 (53%) of 233 cases versus 577 (34%) of 1709 referents. VGDF was associated with COPD (Odds Ratio [OR] 2.5; 95% CI = 1.9 to 3.4); the population attributable fraction was 32%. In the lung function subset, the FEV1/FVC was <70% in 79 (57%); 35 (44%) reported VGDF associated with an OR = 1.6 (95% CI = 0.99 to 2.6) and population attributable fraction 17%. Conclusions: These data support an important role for occupational exposures in COPD.

Screening for Depression in Chronic Obstructive Pulmonary Disease

ABSTRACT Depression and chronic obstructive pulmonary disease (COPD) are major causes of disability. Identifying COPD patients at risk for depression would facilitate the alleviation of an important comorbidity conferring additional risk for poor outcomes. The purpose of this study was to determine the utility of a brief screening measure, the 15-item Geriatric Depression Scale (GDS-15), in detecting the mood disorders in persons with COPD. This is a cross-sectional study of 188 persons with COPD, stratified by age (65 and older versus less than 65) and COPD severity using Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging. Screening cut-points were empirically derived using threshold selection methods and receiver operating characteristic (ROC) curves were estimated. The GDS-15 was used as a screening measure and diagnoses of Major Depressive Disorder (MDD) or other mood disorders were determined using a “gold standard” standardized structured clinical interview. Of the 188 persons with COPD, 25% met criteria for any mood disorder and 11% met criteria for MDD. Optimal threshold estimations suggested a GDS cut score of 5, which yielded adequate sensitivity and specificity in detecting MDD (81% and 87%, respectively) and correctly classified 86% of participants. To detect the presence of any mood disorder, a cut score of 4 was suggested yielding sensitivity and specificity of 67% and 82%, respectively; correctly classifying 79%. These results suggest that mood disorders are relatively common among persons with COPD. The GDS-15 is a useful screening measure to identify patients at risk for depression.

Predictors of Asthma Medication Nonadherence

BACKGROUND The purpose of this study was to describe asthma medication adherence behavior and to identify predictors of inhaled corticosteroid (ICS) underuse and inhaled beta-agonist (IBA) overuse. METHODS Self-reported medication adherence, spirometry, various measures of status, and blood for immunoglobulin E measurement were collected on 158 subjects from a larger cohort of adults with asthma and rhinitis who were prescribed an ICS, an IBA, or both. RESULTS There was a positive association between ICS underuse and higher forced expiratory volume in one second percent (FEV1%) predicted (P = .01) and a negative association with lower income (P = 0.04). IBA overuse was positively associated with greater perceived severity of asthma (P = 0.004) and negatively with higher education level (P = 0.02). CONCLUSIONS Nonadherence to prescribed asthma therapy seems to be influenced by socioeconomic factors and by perceived and actual severity of disease. These factors are important to assess when trying to estimate the degree of medication adherence and its relationship to clinical presentation.