Publications

BACKGROUND

Obesity contributes to respiratory symptoms and exercise limitation, but the relationships between obesity, airflow obstruction (AO), respiratory symptoms and functional limitation are complex.

AIMS

To determine the relationship of obesity with airflow obstruction (AO) and respiratory symptoms in adults without a previous diagnosis of chronic obstructive pulmonary disease (COPD).

METHODS

We analysed data for potential referents recruited to be healthy controls for an ongoing study of COPD. The potential referents had no prior diagnosis of COPD or healthcare utilisation attributed to COPD in the 12 months prior to recruitment. Subjects completed a structured interview and a clinical assessment including body mass index, spirometry, six-minute walk test (SMWT), and the Short Performance Physical Battery (SPPB). Multiple regression analyses were used to test the associations of obesity (body mass index >30 kg/m2) and smoking with AO (forced expiratory volume in 1s/forced vital capacity ratio <0.7). We also tested the association of obesity with respiratory symptoms and impaired functional capacity (SPPB, SMWT), adjusting for AO.

RESULTS

Of 371 subjects (aged 40-65 years), 69 (19%) had AO. In multivariate analysis, smoking was positively associated with AO (per 10 pack-years, OR 1.24; 95% CI 1.04 to 1.49) while obesity was negatively associated with AO (OR 0.54; 95% CI 0.30 to 0.98). Obesity was associated with increased odds of reporting dyspnoea on exertion (OR 3.6; 95% CI 2.0 to 6.4), productive cough (OR 2.5; 95% CI 1.1 to 6.0), and with decrements in SMWT distance (67 ± 9 m; 95% CI 50 to 84 m) and SPPB score (OR 1.9; 95% CI 1.1 to 3.5). None of these outcomes was associated with AO.

CONCLUSIONS

Although AO and obesity are both common among adults without an established COPD diagnosis, obesity (but not AO) is linked to a higher risk of reporting dyspnoea on exertion, productive cough, and poorer functional capacity.

BACKGROUND

Although chronic obstructive pulmonary disease (COPD) is a major cause of disability worldwide, its determinants remain poorly defined.

OBJECTIVE

We hypothesized that both pulmonary and extra-pulmonary factors would predict prospective disablement across a hierarchy of activities in persons with COPD.

METHODS

Six hundred and nine participants were studied at baseline (T0) and 2.5 years later (T1). The Valued Life Activities (VLA) scale quantified disability (10-point scale: 0 = no difficulty and 10 = unable to perform), defining disability as any activity newly rated 'unable to perform' at T1. Predictors included pulmonary (lung function, 6-minute walk distance and COPD severity score) and extra-pulmonary (quadriceps strength and lower extremity function) factors. Prospective disability risk was tested by separate logistic regression models for each predictor (baseline value and its change, T0-T1; odds ratios were scaled at 1 standard deviation per factor. Incident disability across a hierarchy of obligatory, committed and discretionary VLA subscales was compared.

RESULTS

Subjects manifested a 40% or greater increased odds of developing disability for each predictor (baseline and change over time). Disability in discretionary activities developed at a rate 2.2-times higher than observed in committed activities, which was in turn 2.5-times higher than the rate observed in obligatory activities (p < 0.05 for each level).

CONCLUSIONS

Disability is common in COPD. Both pulmonary and extra-pulmonary factors are important in predicting its development.

OBJECTIVE

To assess the contribution of workplace exposures to chronic obstructive pulmonary disease (COPD) risk in a community with a heavy burden of past industrial employment.

METHODS

A random population sample of Sheffield, U.K. residents aged over 55 years (n=4000), enriched with a hospital-based supplemental sample (n=209), was approached for study. A comprehensive self-completed questionnaire elicited physician-made diagnoses, current symptoms, and past workplace exposures. The latter were defined in three ways: self-reported exposure to vapours, gases, dusts and fumes (VGDF); response to a specific exposure checklist; and through a job exposure matrix (JEM) assigning exposure risk likelihood based on job history independent of respondent-reported exposure. A subset of the study group underwent lung function testing. Population attributable risk fractions (PAR%), adjusted for age, sex and smoking, were calculated for association between workplace exposure and COPD.

RESULTS

2001 (50%) questionnaires were returned from the general population sample and 60 (29%) by the hospital supplement. Among 1754 with complete occupational data, any past occupational exposure to VGDF carried an adjusted excess risk for report of a physician's diagnosis of COPD, emphysema, or chronic bronchitis (ORs 3.9; 95% CI 2.7 to 5.8), with a corresponding PAR% value of 58.7% (95% CI 45.6% to 68.7%). The PAR% estimate based on JEM exposure was 31%. From within the subgroup of 571 that underwent lung function testing, VGDF exposure was associated with a PAR% of 20.0% (95% CI -7.2 to 40.3%) for Global initiative for chronic obstructive lung disease (GOLD) 1 (or greater) level of COPD.

CONCLUSION

This heavy industrial community-based population study has confirmed significant associations between reported COPD and both generic VGDF and JEM-defined exposures. This study supports the predominantly international evidence-based notion that workplace conditions are important when considering the current and future respiratory health of the workforce.

BACKGROUND

Silicosis is a progressive, fibrotic, occupational lung disease resulting from inhalation of respirable crystalline silica. This disease is preventable through appropriate workplace practices. We systematically assessed an outbreak of silicosis among patients referred to our center for lung transplant.

METHODS

This retrospective cohort analysis included all patients with a diagnosis of silicosis who were referred for evaluation to the National Lung Transplantation Program in Israel from January 1997 through December 2010. We also compared the incidence of lung transplantation (LTX) due to silicosis in Israel with that of the International Society for Heart and Lung Transplantation (ISHLT) registry.

RESULTS

During the 14-year study period, 25 patients with silicosis were referred for evaluation, including 10 patients who went on to undergo LTX. All patients were exposed by dry cutting a relatively new, artificial, decorative stone product with high crystalline silica content used primarily for kitchen countertops and bathroom fixtures. The patients had moderate-to-severe restrictive lung disease. Two patients developed progressive massive fibrosis; none manifested acute silicosis (silicoproteinosis). Three patients died during follow-up, without LTX. Based on the ISHLT registry incidence, 0.68 silicosis cases would have been expected instead of the 10 observed (incidence ratio, 14.6; 95% CI, 7.02-26.8).

CONCLUSIONS

This silicosis outbreak is important because of the worldwide use of this and similar high-silica-content, artificial stone products. Further cases are likely to occur unless effective preventive measures are undertaken and existing safety practices are enforced.

BACKGROUND

Limited health literacy is associated with poor outcomes in many chronic diseases, but little is known about health literacy in chronic obstructive pulmonary disease (COPD).

OBJECTIVE

To examine the associations between health literacy and both outcomes and health status in COPD. PARTICIPANTS, DESIGN AND MAIN MEASURES: Structured interviews were administered to 277 subjects with self-report of physician-diagnosed COPD, recruited through US random-digit telephone dialing. Health literacy was measured with a validated three-item battery. Multivariable linear regression, controlling for sociodemographics including income and education, determined the cross-sectional associations between health literacy and COPD-related health status: COPD Severity Score, COPD Helplessness Index, and Airways Questionnaire-20R [measuring respiratory-specific health-related quality of life (HRQoL)]. Multivariable logistic regression estimated associations between health literacy and COPD-related hospitalizations and emergency department (ED) visits.

KEY RESULTS

Taking socioeconomic status into account, poorer health literacy (lowest tertile compared to highest tertile) was associated with: worse COPD severity (+2.3 points; 95 % CI 0.3-4.4); greater COPD helplessness (+3.7 points; 95 % CI 1.6-5.8); and worse respiratory-specific HRQoL (+3.5 points; 95 % CI 1.8-4.9). Poorer health literacy, also controlling for the same covariates, was associated with higher likelihood of COPD-related hospitalizations (OR = 6.6; 95 % CI 1.3-33) and COPD-related ED visits (OR = 4.7; 95 % CI 1.5-15). Analyses for trend across health literacy tertiles were statistically significant (p < 0.05) for all above outcomes.

CONCLUSIONS

Independent of socioeconomic status, poor health literacy is associated with greater COPD severity, greater COPD helplessness, worse respiratory-specific HRQoL, and higher odds of COPD-related emergency health-care utilization. These results underscore that COPD patients with poor health literacy may be at particular risk for poor health-related outcomes.

BACKGROUND

Limited data are available on the effects of air travel in patients with pulmonary hypertension (PH), despite their risk of physiologic compromise. We sought to quantify the incidence and severity of hypoxemia experienced by people with PH during commercial air travel.

METHODS

We recruited 34 participants for a prospective observational study during which cabin pressure, oxygen saturation (Sp O 2 ), heart rate, and symptoms were documented serially at multiple predefined time points throughout commercial flights. Oxygen desaturation was defined as SpO2, <85%.

RESULTS

Median flight duration was 3.6 h (range, 1.0-7.3 h). Mean ± SD cabin pressure at cruising altitude was equivalent to the pressure 1,968 ± 371 m (6,456 ± 1,218 ft) above sea level (ASL)(maximum altitude 5 2,621 m [8,600 ft] ASL). Median change in Sp O 2 from sea level to cruising altitude was 2 4.9% (range, 2.0% to 2 15.8%). Nine subjects (26% [95% CI, 12%-38%]) experienced oxygen desaturation during flight (minimum Sp O 2 5 74%). Thirteen subjects (38%) reported symptoms during flight, of whom five also experienced desaturations. Oxygen desaturation was associated with cabin pressures equivalent to . 1,829 m (6,000 ft) ASL, ambulation, and flight duration(all P values , .05).

CONCLUSIONS

Hypoxemia is common among people with PH traveling by air, occurring in one in four people studied. Hypoxemia was associated with lower cabin pressures, ambulation during flight, and longer flight duration. Patients with PH who will be traveling on flights of longer duration or who have a history of oxygen use, including nocturnal use only, should be evaluated for supplemental in-flight oxygen.

OBJECTIVE

This study examined the contribution of perceived social support to the presence of anxiety in persons with chronic obstructive pulmonary disease (COPD).

METHODS

A cross-sectional survey sample of 452 persons with COPD (61.3% female; 53.5% older than 65; 70.8% without a college degree or higher educational achievement, and 54.8% with household income of $40,000 or less) completed a telephone survey. Measures included the anxiety subscale of the Hospital Anxiety and Depression Scale (HADS-A), 5 social support subscales from the Positive and Negative Social Exchanges (PANSE) Scale, a COPD Severity Score (CSS; a weighted algorithmic combination of symptoms and the need for various COPD medical interventions), and the Geriatric Depression Scale, Short Form (GDS-SF). Zero order correlations and a series of multiple regression analyses were calculated.

RESULTS

Multiple regression analysis revealed that the receipt of instrumental support, feeling let down by the failure of others to provide needed help, and unsympathetic or insensitive behavior from others each positively predicted a higher level of patient anxiety in COPD patients, after controlling for demographic variables, smoking status, comorbid depression (GDS) and severity of illness (CSS). Additionally, the control variable of depression was the strongest predictor of anxiety, suggesting a high degree of co-morbidity in this sample.

CONCLUSION

Anxiety and depression are serious co-morbid mental health concerns for persons with COPD. It is important to examine both positive and negative aspects of perceived social support for COPD patients and how they may impact or interact with these mental health concerns.

OBJECTIVES

We estimated the extent to which socioeconomic status (SES) gradients in adult asthma and rhinitis outcomes can be explained by home and neighborhood environmental factors.

METHODS

Using survey data for 515 adults with either asthma or rhinitis, or both, we examined environmental mediators of SES associations with disease severity, using the Severity of Asthma Scale, and health-related quality of life (HRQL), using the Rhinasthma Scale. We defined SES on the basis of education and household income. Potential environmental mediators included home type and ownership, exposures to allergens and irritants, and a summary measure of perceived neighborhood problems. We modeled each outcome as a function of SES, and controlled for age, gender, and potential mediators.

RESULTS

Gradients in SES were apparent in disease severity and HRQL. Living in a rented house partially mediated the SES gradient for both severity and HRQL (P < .01). Higher perceived levels of neighborhood problems were associated with poorer HRQL and partially mediated the income-HRQL relationship (P < .01).

CONCLUSIONS

Differences in home and neighborhood environments partially explained associations of SES with adult asthma and rhinitis outcomes.