The Association between Sexually Transmitted Infections, Length of Service and Other Demographic Factors in the U.S. Military

PLoS One. 2016 Dec 9;11(12):e0167892. doi: 10.1371/journal.pone.0167892. eCollection 2016.


Background: Numerous studies have found higher rates of sexually transmitted infections (STIs) among military personnel than the general population, but the cumulative risk of acquiring STIs throughout an individual's military career has not been described.

Methods: Using ICD-9 diagnosis codes, we analyzed the medical records of 100,005 individuals from all service branches, divided in equal cohorts (n = 6,667) between 1997 and 2011. As women receive frequent STI screening compared to men, these groups were analyzed separately. Incidence rates were calculated for pathogen-specific STIs along with syndromic diagnoses. Descriptive statistics were used to characterize the individuals within each accession year cohort; repeat infections were censored.

Results: The total sample included 29,010 females and 70,995 males. The STI incidence rates (per 100 person-years) for women and men, respectively, were as follows: chlamydia (3.5 and 0.7), gonorrhea (1.1 and 0.4), HIV (0.04 and 0.07) and syphilis (0.14 and 0.15). During the study period, 22% of women and 3.3% of men received a pathogen-specific STI diagnosis; inclusion of syndromic diagnoses increased STI prevalence to 41% and 5.5%, respectively. In multivariate analyses, factors associated with etiologic and syndromic STIs among women included African American race, younger age and fewer years of education. In the overall sample, increasing number of years of service was associated with an increased likelihood of an STI diagnosis (p<0.001 for trend).

Conclusion: In this survey of military personnel, we found very high rates of STI acquisition throughout military service, especially among women, demonstrating that STI-related risk is significant and ongoing throughout military service. Lower STI incidence rates among men may represent under-diagnosis and demonstrate a need for enhancing male-directed screening and diagnostic interventions.

MeSH terms

  • Demography*
  • Female
  • Humans
  • Incidence
  • Male
  • Military Personnel*
  • Sexually Transmitted Diseases / epidemiology*
  • United States / epidemiology

Grant support

This work was supported by the Department of Defense, National Institute of Allergic and Infectious Diseases. Support for this work (IDCRP-069) was provided by the DoD Global Emerging Infections Surveillance and Response System (GEIS) Division of the Armed Forces Health Surveillance Center, award C0689-12-HS, and the Infectious Disease Clinical Research Program (IDCRP), a Department of Defense (DoD) program executed through the Uniformed Services University of the Health Sciences. This project has been funded in part with federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), under Inter-Agency Agreement Y1- AI-5072. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.