Accelerated biological aging and midlife frailty among U.S. military veterans

Injuries characterizing recent military service, such as traumatic brain injury and posttraumatic stress disorder, are linked to accelerated biological aging. If recent veterans have accelerated aging, they might also show early onset of aging-related phenotypes, such as frailty. In this study, we examined the prevalence of frailty and associations with biological aging using data from 1,654 post-9/11 veterans, who were followed for an average of 12.6 years. Biological aging was assessed using DunedinPACE, and frailty was assessed using 11 years of Jen Frailty Index scores from electronic health records. We found a high proportion of frailty-25.5% of post-9/11 veterans met frailty criteria during the study. This is roughly double the prevalence among community-dwelling older adults, despite the cohort's average age of 50.2 years at study end. Veterans with faster aging had higher initial frailty scores (β, 0.21; 95% CI, 0.15-0.27), higher peak frailty scores (β, 0.24; 95% CI, 0.18-0.30), and larger increases in frailty scores over time (β, 0.15; 95% CI, 0.09-0.21, all ps < .001). Faster aging was associated with a 62% (95% CI, 44%-82%) greater rate of incident frailty over the follow-up, while accounting for demographics, baseline health, and smoking. These results suggest post-9/11 veterans are at risk of early onset frailty, and this increased risk could be explained by accelerated rates of biological aging. Future research should replicate these results in nationally representative samples of post-9/11 veterans and explore whether screening for frailty should be implemented at younger ages for veterans.