Normal Lung Function and Mortality in World Trade Center Responders and National Health and Nutrition Examination Survey III Participants

Abstract

Abstract Rationale Low FEV1 is a biomarker of increased mortality. The association of normal lung function and mortality is not well described. Objectives To evaluate the FEV1–mortality association among participants with normal lung function. Methods A total of 10,999 Fire Department of the City of New York (FDNY) responders and 10,901 Third National Health and Nutrition Examination Survey (NHANES III) participants, aged 18–65 years with FEV1 ≥80% predicted, were analyzed, with FEV1 percent predicted calculated using Global Lung Function Initiative Global race-neutral reference equations. Mortality data were obtained from linkages to the National Death Index. Cox proportional hazards models estimated the association between FEV1 and all-cause mortality, controlling for age, sex, race/ethnicity, smoking history, and, for FDNY, work assignment. Cohorts were followed for a maximum of 20.3 years. Measurements and Main Results We observed 504 deaths (4.6%) of 10,999 for FDNY and 1,237 deaths (9.4% [weighted]) of 10,901 for NHANES III. Relative to FEV1 ≥120% predicted, mortality was significantly higher for FEV1 100–109%, 90–99%, and 80–89% predicted in the FDNY cohort. In the NHANES III cohort, mortality was significantly higher for FEV1 90–99% and 80–89% predicted. Each 10% higher predicted FEV1 was associated with 15% (hazard ratio, 0.85; 95% confidence interval, 0.80–0.91) and 23% (hazard ratio, 0.77; 95% confidence interval, 0.71–0.84) lower mortality for FDNY and NHANES III, respectively. Conclusions In both cohorts, higher FEV1 is associated with lower mortality, suggesting higher FEV1 is a biomarker of better health. These findings demonstrate that a single cross-sectional measurement of FEV1 is predictive of mortality over two decades, even when FEV1 is in the normal range.

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