Directly measured secondhand smoke exposure and COPD health outcomes

Mark D Eisner,Edward H Yelin,S Katherine Hammond,John Balmes,Neal Benowitz,Patricia P Katz,Paul D Blanc

doi:10.1186/1471-2466-6-12

Abstract

BackgroundAlthough 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.MethodsWe 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.ResultsThe 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.ConclusionDirectly 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.

Highlights

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
Using these exposure and outcomes data, we examined the longitudinal association between SHS exposure and health status among persons with COPD
Self-reported SHS exposure and COPD-related health outcomes Of the 77 non-smokers with COPD who completed direct SHS monitoring, 26% indicated 1 or more hours of SHS exposure during the past 7 days

Summary

Introduction

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. Personal direct cigarette smoking is the most important single causal factor for developing COPD. The view that cigarette smoking is the sole meaningful factor in the epidemiology and natural history of COPD, is a misconception. Direct cigarette smoking is the major cause of COPD, up to two cases out of ten cannot be attributable solely to this risk factor.[1] Other exposures, secondhand smoke (SHS) exposure and occupational exposures, may be important in the development of COPD.[2,3,4] In terms of disease progression, other initiators of COPD besides direct smoking may influence the course of the disease and its eventual health outcomes. SHS exposure among adults with COPD appears to be common, the effects of SHS have not been systematically examined in persons with established COPD.[5,6]

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Discussion

Conclusion