BACKGROUND

Although occupational exposure is a known risk factor for Chronic Obstructive Pulmonary Disease (COPD), it is difficult to identify specific occupational contributors to COPD at the individual level to guide COPD prevention or for compensation. The aim of this study was to gain an understanding of how different expert clinicians attribute likely causation in COPD.

METHODS

Ten COPD experts and nine occupational lung disease experts assigned occupational contribution ratings to fifteen hypothetical cases of COPD with varying combinations of occupational and smoking exposures. Participants rated the cause of COPD as the percentage contribution to the overall attribution of disease for smoking, occupational exposures and other causes.

RESULTS

Increasing pack-years of tobacco smoking was associated with significantly decreased proportional occupational causation ratings. Increasing weighted occupational exposure was associated with increased occupational causation ratings by 0.28% per unit change. Expert background also contributed significantly to the proportion of occupational causation rated, with COPD experts rating on average a 9.4% greater proportion of occupational causation per case.

CONCLUSION

Our findings support the notion that respiratory physicians are able to assign attribution to different sources of causation in COPD, taking into account both smoking and occupational histories. The recommendations on whether to continue to work in the same job also differ, the COPD experts being more likely to recommend change of work rather than change of work practice.

BACKGROUND

Adjustment for differing risks among patients is usually incorporated into newer payment approaches, and current risk models rely on age, sex, and diagnosis codes. It is unknown the extent to which controlling additionally for disease severity improves cost prediction. Failure to adjust for within-disease variation may create incentives to avoid sicker patients. We address this issue among patients with chronic obstructive pulmonary disease (COPD).

METHODS

Cost and clinical data were collected prospectively from 1202 COPD patients at Kaiser Permanente. Baseline analysis included age, sex, and diagnosis codes (using the Diagnostic Cost Group Relative Risk Score) in a general linear model predicting total medical costs in the following year. We determined whether adding COPD severity measures-forced expiratory volume in 1 second, 6-Minute Walk Test, dyspnea score, body mass index, and BODE Index (composite of the other 4 measures)-improved predictions. Separately, we examined household income as a cost predictor.

RESULTS

Mean costs were $12,334/y. Controlling for Relative Risk Score, each ½ SD worsening in COPD severity factor was associated with $629 to $1135 in increased annual costs (all P<0.01). The lowest stratum of forced expiratory volume in 1 second (<30% normal) predicted $4098 (95% confidence interval, $576-$8773) additional costs. Household income predicted excess costs when added to the baseline model (P=0.038), but this became nonsignificant when also incorporating the BODE Index.

CONCLUSIONS

Disease severity measures explain significant cost variations beyond current risk models, and adding them to such models appears important to fairly compensate organizations that accept responsibility for sicker COPD patients. Appropriately controlling for disease severity also accounts for costs otherwise associated with lower socioeconomic status.

Occupational exposure is a well-recognised modifiable risk factor for asthma, but the relationship between occupational exposure and asthma control has not been studied. We aimed to study this association among working-age adults from the European Community Respiratory Health Survey (ECRHS). Data were available for 7077 participants (mean age 43 years, 45% never-smokers, 5867 without asthma and 1210 with current asthma). Associations between occupational exposure to specific asthmagens and asthma control status (33% with uncontrolled asthma, based on the Global Initiative for Asthma guidelines) were evaluated using logistic and multinomial regressions, adjusted for age, sex and smoking status, with study areas included as a random effect. Statistically significant positive associations were observed between uncontrolled adult-onset asthma and both past 12-month and 10-year exposure to any occupational asthmagens (OR (95% CI) 1.6 (1.0-2.40) and 1.7 (1.2-2.5), respectively); high (1.7 (1.0-2.8) and 1.9 (1.3-2.9), respectively) and low (1.6 (1.0-2.7) and 1.8 (1.2-2.7), respectively) molecular weight agents; and cleaning agents (2.0 (1.1-3.6) and 2.3 (1.4-3.6), respectively), with stronger associations for long-term exposures. These associations were mainly explained by the exacerbation domain of asthma control and no associations were observed between asthmagens and partly controlled asthma. These findings suggest that occupational exposure to asthmagens is associated with uncontrolled adult-onset asthma. Occupational risk factors should be quickly identified to prevent uncontrolled asthma.

OBJECTIVE

To assess the annual lung function decline associated with the reduction of secondhand smoke exposure in a high-altitude industrial workforce.

METHODS

We performed pulmonary function tests annually among 109 high-altitude gold-mine workers over 5 years of follow-up. The first 3 years included greater likelihood of exposure to secondhand smoke exposure before the initiation of extensive smoking restrictions that came into force in the last 2 years of observation.

RESULTS

In repeated measures modeling, taking into account the time elapsed in relation to the smoking ban, there was a 115 ± 9 (standard error) mL per annum decline in lung function before the ban, but a 178 ± 20 (standard error) mL per annum increase afterward (P < 0.001, both slopes).

CONCLUSION

Institution of a workplace smoking ban at high altitude may be beneficial in terms of lung function decline.

BACKGROUND

Lung transplant (LT) aims to extend survival and improve patient-centred outcomes (PCOs) by reducing disability and improving health-related quality of life (HRQL). Few PCO instruments have been validated in LT populations. We aimed to develop and validate a shortened version of the valued life activities (VLA) disability scale specific to LT.

METHODS

We used data from 140 subjects participating in an ongoing cohort study of LT. Subjects completed a survey battery, including VLA items, and physical assessments before LT. To develop a shortened LT-specific VLA (LT-VLA), we iteratively deleted items from a longer 32-item VLA battery, retaining the instrument's conceptual framework, scoring and performance characteristics. We evaluated LT-VLA validity by testing correlations with a HRQL measure (Short Form-12 Physical Function (SF-12 PF) subscale), forced vital capacity % (FVC%) predicted and 6 minute walk distance (6MWD). Responsiveness was evaluated in 84 subjects who completed assessments before and after LT.

RESULTS

The 15-item LT-VLA scoring closely matched the longer VLA (correlations ≥0.96) and had excellent internal consistency (Cronbach's α 0.92). The LT-VLA required only 3 min or less to administer. The LT-VLA, measured as mean difficulty in performing each of the 15 activities queried, correlated with FVC% predicted (r=-0.30), 6MWD (r=-0.38) and SF-12 PF (r=-0.47) (all p<0.01). The LT-VLA mean difficulty was responsive to change from before to after LT (63% improvement; effect size=1.60).

CONCLUSIONS

The LT-VLA is a short, easy to administer, valid and responsive disease-specific PCO instrument that may be useful in clinical and research applications for lung transplantation.

BACKGROUND

While exposure to outdoor particulate matter (PM) has been associated with poor asthma outcomes, few studies have investigated the combined effects of outdoor and indoor PM (including secondhand tobacco smoke).

OBJECTIVE

To examine the associations between PM and asthma outcomes.

METHODS

We analyzed data from a cohort of adults with asthma and rhinitis (n=302; 82% both conditions; 13% asthma only; 5% rhinitis alone) including measures of home PM, tobacco smoke exposure (hair nicotine and self-report), ambient PM from regional monitoring, distance to roadway, and season (wet or dry). The outcomes of interest were frequent respiratory symptoms and forced expiratory volume in 1 second (FEV1) below the lower limit of normal (NHANES reference values). Multivariable regression analyses examined the associations (Odds Ratio [OR] and 95% Confidence Interval [95%CI]) between exposures and these outcomes, adjusted by sociodemographic characteristics.

RESULTS

In adjusted analyses of each exposure, the highest tertile of home PM and season of interview were associated with increased odds for more frequent respiratory symptoms (OR=1.64 95%CI: [1.00, 2.69] and OR=1.66 95%CI: [1.09, 2.51]). The highest tertile of hair nicotine was significantly associated with FEV1 below the lower limit of normal (OR=1.80 95%CI: [1.00, 3.25]). In a model including home PM, ambient PM, hair nicotine, and season, only two associations remained strong: hair nicotine with FEV1 below the lower limit of normal and season of measurement (dry, April-October) with increased respiratory symptoms (OR=1.85 95%CI: [1.00, 3.41] and OR=1.54 95%CI: [1.0, 2.37]). When that model was stratified by sex, the highest tertiles of ambient PM and hair nicotine were associated with FEV1 below the lower limit of normal among women (OR=2.23 95%CI: [1.08, 4.61] and OR=2.90 95%CI: [1.32, 6.38]), but not men. The highest tertile of hair nicotine was also associated with increased respiratory symptoms in women but not men (OR=2.38 95%CI: [1.26, 4.49]). When stratified by age, the middle quartile of ambient PM and the highest hair nicotine tertile were associated with increased respiratory symptoms (OR=2.07 95%CI: [1.01, 4.24] and OR=2.55 95%CI: [1.21, 5.36]) in those under 55 but not in the older stratum.

CONCLUSIONS

Exposure to PM from both home and ambient sources is associated with increased symptoms and lower lung function in adults with asthma, although these associations vary by type of PM, the respiratory outcome studied, sex and age.

RATIONALE

HIV seropositivity has long been considered a contraindication to lung transplantation, primarily because of the potential risks of added immunosuppression. In the past decade, however, experience with kidney and liver transplantation in the setting of HIV infection, with achievement of satisfactory outcomes, has grown considerably. This promising development has created a need to reconsider this contraindication to lung transplantation.

OBJECTIVES

There is presently limited evidence upon which to base medical decision-making regarding lung transplantation in individuals with HIV infection. In our present study, we wished to extend the existing literature by reporting the outcomes of three individuals with HIV infection who underwent lung transplantation at two centers.

METHODS

We compiled data for a case series of three HIV-infected subjects undergoing lung transplantation at two centers.

MEASUREMENTS AND MAIN RESULTS

We reviewed medical records to investigate the effects of lung transplantation on the course of HIV infection, the development of HIV-related opportunistic infections or malignancies, the occurrence of lung transplant and HIV drug interactions, and the extent of acute rejection. Subject 1, who underwent transplantation for HIV-associated pulmonary arterial hypertension, experienced recalcitrant acute rejection requiring a lymphocyte-depleting agent with subsequent rapid development of bronchiolitis obliterans syndrome. Subjects 2 and 3, who underwent transplantation for idiopathic pulmonary fibrosis, experienced mild acute rejection but remain free from chronic rejection at 4 and 2 years after transplant, respectively.

CONCLUSIONS

Lung transplantation may be feasible for carefully selected patients in the setting of controlled HIV infection. On the basis of our experience with three patients, we caution that acute graft rejection may be more common in such patients.

BACKGROUND

Studies of occupational acute mountain sickness (AMS) have not focused on the more severe end of the spectrum to date.

AIMS

To examine risk factors associated with the development of occupational AMS severe enough to receive treatment in a compression chamber.

METHODS

A nested case referent study in a cohort of high-altitude (4000 m) mine workers, comparing cases of severe, chamber-treated AMS to matched referents. Using logistic regression, we tested potential risk factors based on premorbid surveillance examinations, including cigarette smoking (current smoking, smoking intensity and exhaled carbon monoxide [CO]).

RESULTS

There were 15 cases and 30 controls. In multivariate analysis including age, sex and place of residence, current smoking was associated with increased risk of severe AMS (odds ratio [OR] 10.0; 95% confidence interval [CI] 1.5-67.4), taking into account any prior, less severe AMS event, which was also a potent risk factor (OR 33.3; 95% CI 2.8-390). Smoking intensity (cigarettes per day) and exhaled CO were also statistically significantly associated with severe AMS.

CONCLUSIONS

Cigarette smoking is a strong, previously under-appreciated risk factor for severe AMS. Because this is a modifiable factor, these findings suggest that workplace-based smoking cessation should be tested as an intervention to prevent such morbidity.

OBJECTIVE

We sought to quantify absorption of triclosan, a potential endocrine disruptor, in health care workers with occupational exposure to soap containing this chemical.

METHODS

A cross-sectional convenience sample of two groups of 38 health care workers at separate inpatient medical centers: hospital 1 uses 0.3% triclosan soap in all patient care areas; hospital 2 does not use triclosan-containing products. Additional exposure to triclosan-containing personal care products was assessed through a structured questionnaire. Urine triclosan was quantified and the occupational contribution estimated through regression modeling.

RESULTS

Occupational exposure accounted for an incremental triclosan burden of 206 ng/mL (P = 0.02), while triclosan-containing toothpaste use was associated with 146 ng/mL higher levels (P < 0.001).

CONCLUSIONS

Use of triclosan-containing antibacterial soaps in health care settings represents a substantial and potentially biologically relevant source of occupational triclosan exposure.