Worsened longitudinal visit-to-visit-FEV1-variation and mortality in WTC exposed FDNY workers: a 23-year landmark analysis

The World Trade Center (WTC) collapse produced an inhalation disaster. Body Mass index (BMI) is a risk-factor for WTC-related lung injury. Visit-to-visit-forced-expiratory-volume-at-one-second-variation (FEV 1 -variation) is a mortality risk-factor in WTC-exposed Fire Department of New York (FDNY) workers. We hypothesized: worsened-FEV 1 -variation with greater time post-9/11/2001 will be a mortality risk-factor associated with cross sectional BMI and longitudinal weight-variation. Annual WTC-monitoring measured lung function and weight. FEV 1 -variation was quantified as individual-specific coefficient of variation (CV) and FEV 1 -slope-SEM, among 9410 WTC-exposed workers who were alive at the 1/1/2019 Landmark and had ≥ 3 FEV 1 -measurments early (9/12/2001 through 12/31/2009) and later (1/1/2010 through 12/31/2018). Weight-variation quantified as individual-specific weight-CV 9/12/2001 through 12/31/2018. Worsened-FEV 1 -variation was defined as later/early FEV 1 -variation ratio > 1. The outcome was all-cause mortality 1/1/2019 through 12/31/23. Cox regression assessed the 5-year mortality risk of Worsened-FEV 1 -variation. Logistic regression assessed covariates associated with worsened-FEV 1 -variation. Fourty-seven percent (4459/9410) of WTC-exposed FDNY-workers experienced worsened-FEV 1 -variation. an exposure that was associated with 40% greater 5-year mortality risk (HR = 1.40; 95% CI 1.07, 1.89) in a Cox model adjusted for landmark, age, FEV 1 , BMI, weight-variation, and smoking. Similarly, Worsened-FEV 1 -variation defined by FEV 1 -slope-SEM was a mortality risk factor (HR = 1.39; 95% CI 1.05, 1.83). Each 5 kg/m 2 increase in BMI and each 5%CV increased weight-variation was associated with 18% and 17% greater odds of worsened-FEV 1 -variation (OR = 1.18; 95% CI 1.06, 1.27 and OR = 1.17; 95% CI 1.07, 1.27 respectively). Worsened-FEV 1 -variation with greater time post-9/11/2001 is a mortality risk-factor associated with obesity and weight-variation. The association of Worsened-FEV 1 -variation and weight-variation may reflect concurrent metabolic and pulmonary instability that increase vulnerability to death.