Importance of reference group selection in the evaluation of cancer incidence.

Elevated cancer incidence has been reported among World Trade Center (WTC)-exposed responders, with some incidence rate ratios (IRRs) varying over time. This study describes the influence that different reference populations have on relative cancer incidence and temporal trends. Participants from the WTC Combined Rescue/Recovery Cohort (n = 65,691) were observed between 1/1/2002 and 12/31/2015 using data obtained from 13 state cancer registries.

Self-reported chronic rhinosinusitis diagnoses and symptoms in World Trade Center-exposed and non-World Trade Center-exposed United States firefighters.

Background: Greater World Trade Center (WTC) exposure levels have been associated with chronic rhinosinusitis (CRS) diagnoses and symptoms. We aimed to determine whether self-reported CRS is elevated in WTC-exposed Fire Department of the City of New York (FDNY) firefighters when compared with non-WTC-exposed/non-FDNY firefighters and with the general population.

Methods: The study included male WTC-exposed (N = 7840) and non-WTC-exposed (N = 2771) firefighters who were employed on 9/11/2001 and later completed a health survey.

Partial-linear single-index Cox regression models with multiple time-dependent covariates.

Background: In cohort studies with time-to-event outcomes, covariates of interest often have values that change over time. The classical Cox regression model can handle time-dependent covariates but assumes linear effects on the log hazard function, which can be limiting in practice. Furthermore, when multiple correlated covariates are studied, it is of great interest to model their joint effects by allowing a flexible functional form and to delineate their relative contributions to survival risk.

Prevalence of Mild and Severe Cognitive Impairment in World Trade Center Exposed Fire Department of the City of New York (FDNY) and General Emergency Responders.

Background: The emergency personnel who responded to the World Trade Center (WTC) attacks endured severe occupational exposures, yet the prevalence of cognitive impairment remains unknown among WTC-exposed-FDNY-responders. The present study screened for mild and severe cognitive impairment in WTC-exposed FDNY responders using objective tests, compared prevalence rates to a cohort of non-FDNY WTC-exposed responders, and descriptively to meta-analytic estimates of MCI from global, community, and clinical populations.

Methods: A sample of WTC-exposed-FDNY responders (n = 343) was recruited to complete an extensive battery of cognitive, psychological, and physical tests.