Mortality
Mortality of World Trade Center (WTC) Responders by WTC Health Program Enrollment Mst Afroza Parvin* Mst Afroza Parvin Rebecca D. Kehm James E. Cone Mark R. Farfel Rachel Zeig-Owens Baozhen Qiao David G. Goldfarb Moshe Z. Shapiro Tabassum Insaf Andrew C. Todd Charles B. Hall Paolo Boffetta Jiehui Li
Enrollment in the WTC Health Program (WTCHP) has been associated with lower all-cause and cause-specific (cancer and smoking related) mortality risk among WTC responders involved in rescue and recovery efforts in response to the 9/11 terrorist attacks. This study investigates whether differences in comorbidities account for the survival advantage associated with WTCHP enrollment. We followed 9,467 WTC responders in WTCHP and 18,963 not in WTCHP from enrollment to 2020. We ascertained deaths through linkage to NDI. We estimated adjusted HR (AHR) with 95% CI using Cox models and Fine and Gray’s proportional sub-distribution hazards models respectively to determine the association of WTCHP enrollment with all-cause and cause-specific mortality. In calculating AHR, we initially adjusted for age, sex, race/ethnicity, and smoking status, and subsequently adjusted for various types of self-reported physical and mental health comorbidities using inverse probability weighting to balance the groups on comorbidities. We identified 1,658 deaths during follow-up period. Prior to adjusting for comorbidities, WTC responders in WTCHP had significantly lower risks of all-cause (AHR=0.72; 95% CI=0.65-0.81), cancer-specific (0.76; 0.63-0.93), heart disease-specific (0.74; 0.58-0.93), and smoking-related (0.71; 0.60-0.84) mortality compared to those not in WTCHP. However, after applying the weights of comorbidities, lower risks for all-cause (0.84; 0.76-0.94) and smoking-related (0.83; 0.71-0.97) mortality remained significant, but heart disease- (0.92; 0.73-1.14) and cancer-specific (0.84; 0.69-1.01) mortality risks became non-significant. When limiting to those with cancer, cancer-mortality (0.77; 0.60-0.99) was significantly associated with WTCHP enrollment. This study confirms that WTCHP enrollment is associated with reduced all-cause, cancer- and smoking-related mortality. Differences in comorbidities may explain some, but not all, of this survival benefit.