The Case for Classifying the US Army As a Vulnerable Population

Background: A population is vulnerable when disease risk is increased due to participation or assignment in a specific group. For sexually transmitted infections (STIs),  at the population level, gender, young age, sex work, LGBT identification, co-infection with HIV, being institutionalized and being socio-politically displaced have all been identified as vulnerable populations. US Army Soldiers have been identified as a risk group for STIs.  The demographics of this primary population alone may explain much of their elevated burden of many STIs. However, the question remains whether other variables associated with military service increase STI risk above the baseline for the Soldier population.

Methods: We evaluated STI rates for Soldiers compared to civilian data, the impact of deployment to hostile areas, behavioral risk studies, sexual networks, high-risk subgroups and barriers to access medical care.

Results: Rates for gonorrhea and chlamydia exceed age and gender stratified rates for the general population.  In the military, low rates of condom use, high sexual concurrency, binge drinking, and other individual risk factors were reported in the literature. Both local and distant sexual bridging, and a high risk demographic population were associated with increased risk of STIs in military sexual networks. Available information indicated LGBT soldiers as well as those with behavioral health disorders may perceive barriers to care that are unique to military service, increasing their risk.

Conclusions: It is difficult to determine the attributable STI risk contributed by Army service as there is no counterfactual comparison group. The demographics and baseline risk behaviors of our population suggest a high STI risk even in the absence of military service. However, as with other vulnerable populations, there are situations and circumstances related to the social characteristics of the Army that likely lead to increased risk. Considering the available data, we conclude the Army meets the definition of a vulnerable population.