Blood Leukocyte Concentrations, FEV1 Decline, and Airflow Limitation. A 15-Year Longitudinal Study of World Trade Center–exposed Firefighters

Abstract Rationale Rescue/recovery work at the World Trade Center disaster site (WTC) caused a proximate decline in lung function in Fire Department of the City of New York firefighters. A subset of this cohort experienced an accelerated rate of lung function decline over 15 years of post–September 11, 2001 (9/11) follow-up. Objectives To determine if early postexposure blood leukocyte concentrations are biomarkers for subsequent FEV1 decline and incident airflow limitation. Methods Individual rates of forced expiratory volume in 1 second (FEV1) change were calculated for 9,434 firefighters using 88,709 spirometric measurements taken between September 11, 2001, and September 10, 2016. We categorized FEV1 change rates into three trajectories: accelerated FEV1 decline (FEV1 loss >64 ml/yr), expected FEV1 decline (FEV1 loss…