Don’t sleep on sleep health: How different types of combat injuries are associated with long-term sleep symptoms in UK Armed Forces personnel
Recent research1 from the ADVANCE study explored sleep health and found that patterns of symptoms indicative of moderate-severe sleep problems were more likely to be reported by UK personnel who sustained injuries without limb loss compared to uninjured personnel, whereas those injured with limb loss were not. Low sleep duration (less than 6 hours per night) was prevalent overall, whether injured or not, and more common than expected based on UK general population norms.
What is the ADVANCE study?
The ADVANCE Study investigates the physical and psychosocial outcomes of combat casualties in the long-term. The study has 1,145 participants who served in the Afghanistan conflict of 2002-2014. Half of the cohort sustained serious physical combat injuries, and the other half are demographically similar personnel who sustained no such injuries (the comparison group). The participants will attend six study visits over a 20-year period.
What does this piece of ADVANCE research look at?
Military personnel have specific risk factors for poor sleep health, including learnt behaviours during military deployments and mental/physical health conditions that might affect sleep health. But whilst sleep might seem like a simple concept, it’s actually pretty complex. Sleep health comprises multiple qualities, including duration, efficiency, perceived quality or how much sleep interferes with doing your day-to-day activities. As such, it can be complicated to research.
Utilising a technique called latent class analysis, we investigate underlying patterns of symptoms in the ADVANCE cohort. We hypothesised that UK Armed Forces personnel who sustained serious physical combat injuries would be more likely to present with patterns of symptoms indicative of poor sleep health compared to demographically similar personnel who sustained no such injuries.
What were the findings?
A simple pattern emerges in the data suggesting a group of individuals who have no or minor sleep problems and a group of individuals who report moderate-severe sleep problems. Overall, we see that injured personnel were 18% more likely to report moderate-severe sleep problems compared to the uninjured group. However, specific injury profiles carry with them differing risks of reporting sleep problems. Surprisingly, injuries with associated limb loss had a similar risk of reporting moderate-severe sleep problems compared to the uninjured group, whereas those who sustained injuries without associated limb loss had a 24% increased risk.
We also looked at sleep duration in closer detail. Low sleep duration, defined as less than 6 hours per night, and long sleep duration, defined as more than 8 hours per night, have associated risks of long-term health problems. We observed that individuals who sustained injuries with associated limb loss had similar risk of reporting low sleep duration as the uninjured group, but a 185% increased risk of reporting long sleep duration! Conversely, we observed that individuals who sustained injuries without limb loss had a 29% increased risk of reporting low sleep duration compared to the uninjured group, but similar risk of reporting long sleep duration.
What do the findings mean?
Sustaining a combat injury is associated with worse sleep health, but nuances exist in exactly how depending on the injury profile of the individual. Importantly, we saw a large portion of the entire ADVANCE cohort reported low sleep duration. In the UK general population, rates of low sleep are estimated to be around 10.6% in men. In the ADVANCE cohort, we observed double that rate in the uninjured group alone, with even greater rates observed in those who sustained injuries without associated limb loss. Sleep health can have a considerable impact on a person’s long-term well-being, and reflects an area of health that may be an excellent target for therapeutic intervention.
Future work
This research highlights how complex and nuanced sleep health is and how much more there is to understand. That’s why we’re excited to have ADVANCE-SLEEP, an ongoing PhD project conducted by Grace Williamson at King’s Centre for Military Health Research that will dig deeper into sleep health following serious physical combat injuries in the ADVANCE cohort. Using data from multiple ADVANCE study visits, this work will look at how sleep health trajectories unfold over time depending on injury status and how sleep health is associated with physical health outcomes. This project will also include interviews with ADVANCE participants about their experiences of poor sleep from deployment to the present day, including causes, impact and support needs. Together, this work will help build a richer picture of sleep health following serious physical combat injuries, with implications for policy, clinical care and support pathways for veterans.
Many thanks to Dr Dan Dyball and Grace Williamson for writing this Research Spotlight.
References
1. Dyball, D., Waldron, M., Schofield, S., Williamson, G., Bennett, A. N., Boos, C. J., Bull, A. M. J., Cullinan, P., & Fear, N. T. (2026). Multidimensional qualities of sleep health following serious physical combat injuries: A latent class analysis: The ADVANCE cohort study. Sleep Medicine, 138, 108717. https://doi.org/10.1016/j.sleep.2025.108717
