Association of Lung Function Decline with All-cause and Cancer-cause Mortality after World Trade Center Dust Exposure

In numerous cohorts, lung function decline is associated with all-cause and cardiovascular-cause mortality but the association between forced expiratory volume in one second (FEV1) decline and cancer-cause mortality, particularly after occupational/environmental exposure(s), is unclear. Exposure to dust/smoke from the World Trade Center (WTC) disaster caused inflammation and lung injury in Fire Department of the City of New York (FDNY) rescue/recovery workers. In addition, prior research found that over 10% of the cohort experienced greater than twice the age-related decline in FEV1 (≥64 mL/year).To evaluate the association of longitudinal lung function with all-cause and cancer-cause mortality after exposure to the WTC disaster.We conducted a prospective cohort study using longitudinal pre-bronchodilator FEV1 data for 12,264 WTC-exposed FDNY firefighters and emergency medical service (EMS) providers. All-cause and cancer-cause mortality were ascertained using National Death Index data from 9/12/2001-12/31/2021. Joint longitudinal survival models evaluated the association of baseline FEV1 and change in FEV1 from baseline with all-cause and cancer-cause mortality adjusted for age, race/ethnicity, height, smoking, work assignment (firefighter vs. EMS providers) and WTC exposure.By 12/31/2021, 607/12,264 (4.9%) of the cohort had died (crude rate=259.5/100,000 person-years) and 190/12,264 (1.5%) had died from cancer (crude rate=81.2/100,000 person-years). Baseline FEV1 was ≥80% predicted in 10,970/12,264 (89.4%); final FEV1 was ≥80% in 9,996 (81.5%). Lower FEV1 at baseline was associated with greater risk for all-cause mortality (hazard ratio [HR] per liter=2.32; 95% CI=1.98-2.72) and cancer-cause mortality (HR per liter=1.99; 95% CI=1.49-2.66). Longitudinally, each 100 mL/year decline in FEV1 was associated with an 11% increase in all-cause mortality (HR=1.11; 95% CI=1.06-1.15) and a 7% increase in cancer-cause mortality (HR=1.07; 95% CI=1.00-1.15). Compared with FEV1 decline <64 mL/year, those with FEV1 decline ≥64 mL/year had higher all-cause (HR=2.91; 95% CI=2.37-3.56) and cancer-cause mortality (HR=2.68; 95% CI=1.90-3.79).Baseline FEV1 and longitudinal FEV1 decline are associated with increased risk of all-cause and cancer-cause mortality in a previously healthy occupational cohort, the majority of whom had normal lung function, after intense exposure to dust/smoke. Further investigation is needed to define pathways by which lung function impacts mortality after an irritant exposure.