Health Outcomes Associated with Lung Function Decline and Respiratory Symptoms and Disease in a Community Cohort

Abstract

Background: In workplace respiratory disease prevention, a thorough understanding is needed of the relative contributions of lung function loss and respiratory symptoms in predicting adverse health outcomes. Methods: Copenhagen City Heart Study respiratory data collected at 4 examinations (1976–2003) and morbidity and mortality data were used to investigate these relationships. With 15 or more years of follow-up for a hospital diagnosis of chronic obstructive pulmonary disease (COPD) morbidity, COPD or coronary heart disease (CHD) mortality, and all-cause mortality, risks for these outcomes were estimated in relation to asthma, chronic bronchitis, shortness of breath, and lung function level at examination 2 (1981–1983) or lung function decline established from examinations 1 (1976–1978) to 2 using 4 measures (FEV₁ slope, FEV₁ relative slope, American College of Occupational and Environmental Medicine's Longitudinal Normal Limit [LNL], or a limit of 90 milliliters per year [ml/yr]). These risks were estimated by hazard ratios (HR) and 95% confidence intervals (CI) adjusted for age, height-adjusted baseline forced expiratory volume in 1 second (FEV₁/height²), and height. Results: For COPD morbidity, the increasing trend in the HR (95% CI) by quartiles of the FEV₁ slope reached a maximum of 3.77 (2.76–5.15) for males, 6.12 (4.63–8.10) for females, and 4.14 (1.57–10.90) for never-smokers. Significant increasing trends were also observed for mortality, with females at higher risk. Conclusion: Lung function decline was associated with increased risk of COPD morbidity and mortality emphasizing the need to monitor lung function change over time in at-risk occupational populations.

Keywords::

• Spirometry
• Respiratory symptoms
• COPD
• Mortality
• Morbidity

ACKNOWLEDGMENTS

Funding was received from the National Institute for Occupational Safety and Health. The authors would like recognize Drs. Christopher Martin, Edward Petsonk, Anoop Shankar, and Ms. Patricia Schleiff for their helpful comments.