Publications

BACKGROUND

Although personal cigarette smoking is the most important cause and modulator of chronic obstructive pulmonary disease (COPD), secondhand smoke (SHS) exposure could influence the course of the disease. Despite the importance of this question, the impact of SHS exposure on COPD health outcomes remains unknown.

METHODS

We used data from two waves of a population-based multiwave U.S. cohort study of adults with COPD. 77 non-smoking respondents with a diagnosis of COPD completed direct SHS monitoring based on urine cotinine and a personal badge that measures nicotine. We evaluated the longitudinal impact of SHS exposure on validated measures of COPD severity, physical health status, quality of life (QOL), and dyspnea measured at one year follow-up.

RESULTS

The highest level of SHS exposure, as measured by urine cotinine, was cross-sectionally associated with poorer COPD severity (mean score increment 4.7 pts; 95% CI 0.6 to 8.9) and dyspnea (1.0 pts; 95% CI 0.4 to 1.7) after controlling for covariates. In longitudinal analysis, the highest level of baseline cotinine was associated with worse COPD severity (4.7 points; 95% CI -0.1 to 9.4; p = 0.054), disease-specific QOL (2.9 pts; -0.16 to 5.9; p = 0.063), and dyspnea (0.9 pts; 95% CI 0.2 to 1.6 pts; p < 0.05), although the confidence intervals did not always exclude the no effect level.

CONCLUSION

Directly measured SHS exposure appears to adversely influence health outcomes in COPD, independent of personal smoking. Because SHS is a modifiable risk factor, clinicians should assess SHS exposure in their patients and counsel its avoidance. In public health terms, the effects of SHS exposure on this vulnerable subpopulation provide a further rationale for laws prohibiting public smoking.

The aim of the present study was to predict which patients with severe or difficult-to-treat asthma are at highest risk for healthcare utilisation can be predicted so as to optimise clinical management. Data were derived from 2,821 adults with asthma enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study. Multiple potential predictors were assessed at baseline using a systematic algorithm employing stepwise logistic regression. Outcomes were asthma-related hospitalisations or emergency department (ED) visits within 6 months following baseline. Overall, 239 subjects (8.5%) reported hospitalisation or ED visits at follow-up. Predictors retained after multivariate analysis were as follows: younger age; female sex; non-white race; body mass index > or =35 kg x m(-2); post-bronchodilator per cent predicted forced vital capacity <70%; history of pneumonia; diabetes; cataracts; intubation for asthma; and three or more steroid bursts in the prior 3 months. A final risk score derived from the logistic regression model ranged from 0-18 and was highly predictive (c-index: 0.78) of hospitalisation or ED visits. This tool was re-tested in a prospective validation using outcomes at 12- to 18-months follow-up among the same cohort (c-index: 0.77). The risk score derived is a clinically useful tool for assessing the likelihood of asthma-related hospitalisation or emergency department visits in adults with severe and difficult-to-treat asthma.

BACKGROUND

The relationship between stress and quality of life in adults with asthma has not been well studied. Stress, quantified by negative life events, may be linked to quality of life in asthma through multiple pathways, including increase in disease severity and adverse effects on socioeconomic status (SES).

METHODS

The responses to a self-completed questionnaire assessing negative life events (NLEs) in the previous 12 months (from a 24-item checklist) among 189 adults with asthma from a well-characterised cohort were analysed. The relationship between the number of NLEs reported and asthma-specific quality of life (AQOL) was measured with the Marks instrument. General linear modelling was used to test the conjoint effects of NLEs, SES and disease severity based on the Severity of Asthma Score, a validated acute and chronic disease measure.

RESULTS

Those with annual family incomes < 60,000 dollars reported significantly more NLEs than those with higher incomes (p = 0.03). The number of NLEs did not differ significantly between those with forced expiratory volume in 1 s <80% predicted and those with >80% predicted, nor among those with lower compared with higher Severity of Asthma Score. The frequency of NLEs was associated with poorer (higher numerical score) AQOL (p = 0.002). When studied together in the same model, combinations of income level and asthma severity (greater or lesser Severity of Asthma Score; p < 0.001) and number of NLEs (p = 0.03) were both significantly associated with AQOL.

CONCLUSION

NLEs are associated with quality of life among adults with asthma, especially among those of lower SES. Clinicians should be aware of this relationship, especially in vulnerable patient subsets.

PURPOSE

We aimed to elucidate the prevalence of and risk factors for work disability in severe adult asthma and to evaluate the impact of work disability on downstream health outcomes.

METHODS

We used data from a prospective cohort study of 465 adults with severe asthma. Structured telephone interviews ascertained asthma status and employment history. A job exposure matrix (JEM) was used to characterize the likelihood of workplace exposure to "asthmagens."

RESULTS

The prevalence of asthma-related complete work disability was 14% among working-age adults with severe asthma (95% confidence interval, 11%-18%). Among those who were currently employed, the prevalence of partial work disability was 38% (95% confidence interval, 31%-45%). Sociodemographic (P = .027) and medical factors (P = .020) were related to the risk of complete work disability. Both sociodemographic characteristics (P = .06) and work exposures based on the JEM (P = .012) were related to partial work disability. In additional models, poorer asthma severity, physical health status, and mental health status were all associated with a higher risk of complete and partial work disability.

CONCLUSIONS

Work disability is common among adults with severe asthma. There are three sets of risk factors for work disability that are potentially modifiable: smoking, workplace exposures, and asthma severity.

INTRODUCTION

Little is known about behaviors linked to gamma hydroxybutyrate (GHB) morbidity.

METHODS

We surveyed 131 GHB users, using logistic regression to test the associations between the high risk behaviors and hospital treatment for GHB (26 [20%] of subjects).

RESULTS

Increased risk of GHB hospital treatment was associated with: co-ingestion of ethanol (OR 5.2; 95% CI 1.7-16), driving under the influence of GHB (OR 3.2; 95%, CI 1.3-7.8),use of GHB to treat withdrawal symptoms (OR 2.9; 95% CI 1.1-7.9), and co-ingestion of ketamine (OR 2.7; 95% CI 1.1-6.7).

CONCLUSION

Targeted prevention activities could focus on selected high-risk behaviors.

BACKGROUND

Low body mass index has been associated with increased mortality in severe COPD. The impact of body composition earlier in the disease remains unclear. We studied the impact of body composition on the risk of functional limitation in COPD.

METHODS

We used bioelectrical impedance to estimate body composition in a cohort of 355 younger adults with COPD who had a broad spectrum of severity.

RESULTS

Among women, a higher lean-to-fat ratio was associated with a lower risk of self-reported functional limitation after controlling for age, height, pulmonary function impairment, race, education, and smoking history (OR 0.45 per 0.50 increment in lean-to-fat ratio; 95% CI 0.28 to 0.74). Among men, a higher lean-to-fat ratio was associated with a greater distance walked in 6 minutes (mean difference 40 meters per 0.50 ratio increment; 95% CI 9 to 71 meters). In women, the lean-to-fat ratio was associated with an even greater distance walked (mean difference 162 meters per 0.50 increment; 95% CI 97 to 228 meters). In women, higher lean-to-fat ratio was also associated with better Short Physical Performance Battery Scores. In further analysis, the accumulation of greater fat mass, and not the loss of lean mass, was most strongly associated with functional limitation among both sexes.

CONCLUSION

Body composition is an important non-pulmonary impairment that modulates the risk of functional limitation in COPD, even after taking pulmonary function into account. Body composition abnormalities may represent an important area for screening and preventive intervention in COPD.

OBJECTIVE

The authors examined the relations between self-reported work tasks, use of cleaning products and latex glove use with new-onset asthma among nurses and other healthcare workers in the European Community Respiratory Health Survey (ECRHS II).

METHODS

In a random population sample of adults from 22 European sites, 332 participants reported working in nursing and other related healthcare jobs during the nine-year ECRHS II follow-up period and responded to a supplemental questionnaire about their principal work settings, occupational tasks, products used at work and respiratory symptoms. Poisson regression models with robust error variances were used to compare the risk of new-onset asthma among healthcare workers with each exposure to that of respondents who reported professional or administrative occupations during the entire follow-up period (n = 2481).

RESULTS

Twenty (6%) healthcare workers and 131 (5%) members of the referent population reported new-onset asthma. Compared to the referent group, the authors observed increased risks among hospital technicians (RR 4.63; 95% CI 1.87 to 11.5) and among those using ammonia and/or bleach at work (RR 2.16; 95% CI 1.03 to 4.53).

CONCLUSIONS

In the ECRHS II cohort, hospital technicians and other healthcare workers experience increased risks of new-onset current asthma, possibly due to specific products used at work.

This review critically evaluates the recent scientific literature relevant to occupational risk factors for chronic obstructive pulmonary disease (COPD) and chronic bronchitis. The 2003 American Thoracic Society statement on the occupational contribution to the burden of airway disease synthesized relevant data on this topic through 1999. Since 2000, 14 separate studies have published values or provide data that allow estimation of the population attributable risk per cent (PAR%) for the proportion of chronic bronchitis or COPD due to work-related factors. Based on data since 2000, the median PAR% value for both chronic bronchitis and COPD is 15%. A number of additional studies have been published that underscore the association between specific occupational exposures and airflow obstruction. In addition, data are emerging that indicate the extent to which COPD is a cause of work disability; limited data raise the possibility that among those with occupational COPD, disability may be even more prominent. This review supports previous analyses concluding that there is a causal association between work-related exposures and COPD.

INTRODUCTION

As part of a larger study assessing the covariates and outcomes of GHB use, we developed a telephone-survey instrument for hospitalized GHB exposed patients identified through poison control center surveillance and for self-identified GHB users recruited from the general public.

METHODS

We used an iterative review process with an interdisciplinary team, including pharmacists, a physician, and a medical anthropologist. In designing the structured, telephone-survey instrument, we prioritized inclusion of validated, drug-specific, and generic questionnaire batteries or individual items related to GHB or to other drugs of abuse. Only one published survey instrument specific to GHB use was identified, which we extensively expanded and modified. We also developed a number of GHB-specific items new to this survey. Finally, we included items from the National Survey on Drug Use & Health, CAGE questionnaire items on alcohol abuse, the SF-12 instrument, and selected National Health Interview items.

RESULTS

The final questionnaire consisted of 272 content items, the majority of which required simple yes or no responses. The bulk of the items (74%) were GHB-specific. The questionnaire was easily administered using computer-assisted telephone interview (CATI) software. A total of 131 interviews were administered with a mean administration time of 33+/-10 minutes. The instrument can also be used in other interview formats.

CONCLUSION

Developing a successful questionnaire calls for a multidisciplinary and systematic process. Structured, telephone administered surveys are particularly suited to expand and explore the basic information obtained by poison centers for case management.