As the World Trade Center (WTC) General Responder Cohort ages, it is imperative to study their aging process and identify factors that can be targeted for interventions.

Our goal was to utilize a previously developed WTC Clinical Frailty Index (CFI) to identify distinct frailty trajectories and associated factors in this cohort.

A latent class mixed model evaluated frailty trajectories using WTC CFIs. Multinomial regression models were used to assess associations between frailty trajectory and sociodemographic and WTC characteristics.

We utilized data collected during routine WTC monitoring visits from 2004 until 2021.

The participants were WTC general responders.

Relative risk ratios (RRR) assessed associations with a 95 % confidence interval (CI).

Three distinct linear frailty trajectories were identified: high CFI (indicating higher frailty), low CFI, and progressively increasing CFI. Compared with the low CFI group, females were more likely to be in the high CFI and progressively increasing CFI groups (RRR 1.66, 95 %CI 1.46, 1.90; RRR 1.32, 95 %CI 1.15, 1.53, respectively). Education beyond high school and elevated income were protective against high CFI and progressively increasing CFI groups. Individuals that self-identified as Hispanic had an elevated RRR for the high CFI group (RRR 1.17, 95 %CI 1.04, 1.31). Occupation on 9/11, such as construction and maintenance and repair, as well as high/very high WTC exposure were significantly associated with both the high CFI and progressively increasing CFI groups.

Several sociodemographic and WTC variables were associated with more hazardous frailty trajectories in WTC general responders. This work is beneficial to informing and directing future interventions for those at higher-risk for more hazardous frailty progression.