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The number of women who are active duty service members or veterans of the U.S. military is increasing. Studies among young, unmarried, active duty servicewomen who are sexually active indicate a high prevalence of risky sexual behaviors, including inconsistent condom use, multiple sexual partners, and binge drinking, that lead to unintended and unsafe sex. These high-risk sexual practices likely contribute to chlamydia infection rates that are higher than the rates in the U.S. general population. Human papillomavirus (HPV) infection and cervical dysplasia may also be higher among young, active duty servicewomen. Little is known about the sexual practices and rates of sexually transmitted infections among older servicewomen and women veterans; however, women veterans with a history of sexual assault may be at high risk for HPV infection and cervical dysplasia. To address the reproductive health needs of military women, investigations into the prevalence of unsafe sexual behaviors and consequent infection among older servicewomen and women veterans are needed. Direct comparison of military and civilian women is needed to determine if servicewomen are a truly high-risk group. Additionally, subgroups of military women at greatest risk for these adverse reproductive health outcomes need to be identified.
The proportion of female active duty personnel who serve in the U.S. military is steadily increasing, from 2% in 1973 to approximately 15% currently.1–3 The population of female veterans is also rising. There are at present more than 1.8 million U.S. female veterans, comprising 8% of the total veteran population.4–6 By 2036, it is projected that the proportion of female veterans will reach 15% (Fig. 1).7
Compared to the general population of U.S. women, women in the military may be at higher risk for sexually transmitted infections (STIs) and human papillomavirus (HPV)-related diseases. Active duty women and female veterans tend to be young and unmarried and belong to racial and ethnic minority groups.3,11 Each of these demographic factors is associated with an increased risk of STIs and cervical dysplasia.12–16 Furthermore, studies of active duty servicewomen, primarily new recruits, reveal a high prevalence of unsafe sexual practices, including sporadic condom use, multiple sexual partners, and binge drinking, which compromises barrier contraceptive use.17–19 There are limited data on the risks to these women as they transition out of military service and join the veteran population.
The purpose of this article is to review the literature on high-risk sexual behaviors, rates of STIs, and the burden of HPV-related disease among active duty and veteran women. Data on the U.S. general population are also presented; however, comparison between these populations is imperfect. We explored the literature via a PubMed search using terms including sexual behavior, unsafe sex, multiple sexual partners, condoms, chlamydia, gonorrhea, HIV, HPV, cervical dysplasia, cervical cancer screening, military, veterans, and women and also searched reference lists of relevant articles for additional data. Based on this review, recommendations for future research are provided to evaluate and potentially reduce the incidence of STIs among military women.
Some groups of active duty servicewomen, particularly those who are unmarried, young, and new to military service, engage in high-risk sexual behavior. This is defined by the U.S. Preventive Services Task Force (USPSTF) as using condoms inconsistently, having multiple current partners, having a new partner, or having sex while under the influence of alcohol or drugs.20 These sexual practices may place military women at increased risk for acquiring an STI.
In Department of Defense (DOD) surveys assessing health behaviors of active duty military personnel, only 33% of sexually active unmarried women reported using condoms during last intercourse in 2002, which increased marginally to 36% by 2005.17,21 Among both unmarried women and men who responded to the survey, reported condom use with last intercourse was higher for those <21 compared to 21–25 years old, those with lower educational levels, and service members with enlisted compared to officer rank. Those who reported a higher number of sexual partners in the past year were also more likely to report condom use at last intercourse but less likely to use condoms with each act of intercourse.17 In a smaller survey of 131 Army servicewomen, nearly 70% did not use condoms regularly, and <40% used condoms with their last self-reported casual sexual partner.22 This is comparable to women in the U.S. general population who endorsed high-risk sexual behavior, among whom only 34% reported condom use at last intercourse.23 (Table 1A).
A qualitative study of women enlisted in the Navy revealed potential barriers to condom use while in the military. These women reported feeling stigmatized as promiscuous if they requested condoms and believed their male counterparts to be exempt from the same criticism.24 They also reported not using condoms because if found this would be evidence of violation of the policy prohibiting sexual activity while deployed.24
Although there are limited data on high-risk sexual practices among military women, some studies have reported a high prevalence of new or concurrent sexual partners. In a study of 1,095 male and female Army recruits, nearly 60% reported >1 sexual partner within the last year.18 Another study of 13,204 female Army recruits conducted between 1996 and 1997 found that in the prior 90 days, 27% of women had >1 partner, 31% had a new partner, and only 17% reported that her partner always wore condoms.25 In the U.S. general population, risk factors for multiple new partners include black race, alcohol or drug use, and young age (≤13 years old) at first intercourse.26 Given limited data in military populations, risk factors for multiple sexual partners have not been identified; however, younger age may be associated with high-risk sexual practices among servicewomen. In a 1991 study of female Army personnel, adolescents were found to have a greater number of sexual partners, less reproductive health knowledge, and higher likelihood of not using any method of contraception compared to their older counterparts19 (Table 1B). In a study of 999 female veterans, the proportion who reported having a partner who had concurrent sexual partners increased from 30% before joining the military to 42% during military service.27
In the U.S. general population, 6%–7% of women per year reported binge drinking,28 whereas in a survey of 1,095 Army recruits, 33% of female respondents reported binge drinking in the past month.18 Binge drinking has been associated with unsafe sexual practices and unwanted sexual activity among female military personnel. Female Army recruits who participated in binge drinking were less likely to report using effective methods of contraception during their last sexual encounter.18 A study of 1,841 female Marine Corps recruits revealed that 31% reported having sex under the influence of alcohol or drugs in the 3 months before recruit training.29 In a qualitative study of Navy personnel, female respondents stated that servicewomen participated in binge drinking to fit in with a predominantly male crew; however, this left women vulnerable to nonconsensual or compromising sexual encounters24 (Table 1C). When women veterans were asked about their previous sexual behaviors, 24% stated they had unintended sex after drinking alcohol or using drugs before joining the military, and 33% reported this occurrence during military service.27
Limited condom use and high-risk sexual encounters among some groups of active duty military personnel may result in STI rates that are higher than in the general population. Indeed, rates of STIs are reported to be up to seven times higher in military than civilian populations.22 In particular, the rates of STIs in military recruits, young military personnel, and military ethnic minorities are above the national average.21,30,31 In a study of 1,841 female Marine Corps recruits who were screened for chlamydia, gonorrhea, and trichomoniasis upon entry to the military, 14% tested positive for an STI compared to 8% of similar aged women in the general population tested during the same time frame.29 In studies in which asymptomatic military personnel were randomly screened for STIs, the prevalence of chlamydial infection was between 5% and 10% overall.25,32,33 This estimate is significantly higher than that in studies among women in the general population who were randomly screened, where chlamydia prevalence is between 2% and 5%.14,34 Chlamydia rates among servicewomen who seek care at STI clinics are comparatively higher than among those who are screened as part of routine protocol. A 2002 epidemiologic investigation of >800 women who lived on or near a U.S. Army base and sought care at an on-base infectious disease screening clinic found that approximately 19% of servicewomen were infected with chlamydia and 3% had gonorrhea.35 Another study at the same military base found the rate of chlamydial infection among female active duty soldiers to be 3–7-fold higher than that in the general population living within the same state over a 6-year period after standardizing for age and race/ethnicity.36
Risk factors for chlamydial infection among female military personnel include younger age, black race, having >1 sexual partner, having a new sexual partner, or having a partner who inconsistently used condoms in the last 90 days.25 Additionally, women with lower military rank had higher odds of chlamydial infection compared to their higher ranking counterparts.35 Gender is also a risk factor for STI infection. Among active duty personnel deployed to Iraq and Afghanistan, women were found to have higher rates of gonorrhea and chlamydia infection than their male counterparts.37 Female gender, young age, and high-risk sexual practices have been shown to be risk factors for reinfection. A study of 11,771 active duty Army personnel found that women were more likely than men to be reinfected with chlamydia and confirmed that women in their early 20s were at highest risk for reinfection.38 Compared to new recruits who tested negative for an STI upon entry in the military, those who tested positive were more likely to test positive again after returning from vacation during recruit training, and those aged 19–21 years who tested positive were more likely to report having a casual sex partner during vacation.39
Data on the prevalence of other STIs, including syphilis or herpes simplex, among servicewomen is lacking. Overall, the rates of HIV infection within the military are declining but there is a slower decline among women compared to men.40–41 Furthermore, the incidence of HIV infection is higher for minority compared to white women in the military.40–42 Given the different years of evaluation and methods of calculation, it is difficult to compare HIV incidence among military personnel to that in the general population (Table 2).
In addition to chlamydia, the prevalence of cervical dysplasia may be higher among servicewomen compared to women in the general U.S. population. In a study examining 126,024 cervical cytology records of women obtaining care at U.S. Armed Forces medical facilities, 4% of active duty servicewomen had low-grade or high grade squamous intraepithelial lesions (SIL) or lesions consistent with carcinoma compared to 1% of wives who were military beneficiaries.43 In a study evaluating 76,675 cervical cytology smears obtained from Army medical facilities, 2.5% demonstrated lesions more severe than atypical squamous cells of undetermined significance.44 Combining active duty servicewomen with military beneficiaries not serving in the Armed Forces may have caused in this lower prevalence rate. However, a study conducted in 1993 also reported a 3% prevalence rate of low-grade or high grade SIL among female military recruits.45 An older study conducted among 332 female cadets with an average age of 22 years demonstrated that 5% had cervical cytology results consistent with low-grade or high grade SIL.46 Based on the evidence presented, the prevalence of low-grade or high-grade SIL among military women is between 2.5% and 5%. In comparison, a study conducted at a civilian health maintenance organization (HMO) between 1997 and 2002 revealed <1% prevalence of low-grade or high-grade SIL.47 Comparisons between the civilian and military populations are imperfect, given differences in study methods, years of ascertainment, and reporting of results. Better designed studies are needed to determine if cervical dysplasia rates are truly higher among military women compared to the general population, as these data would suggest (Table 3A).
Although data are limited, the prevalence of HPV infection may also be higher among women in the military compared to those in the general population. In studies among active duty servicewomen seeking care at an Army medical center STI screening clinic, prevalence of any HPV type ranged between 36% and 51%,48,49 which is far higher than in the general population of U.S. women (27%, 95% confidence interval [CI] 23%-31%), but similar to that found in U.S. women 20–24 years old (45%, (95% CI 36%-55%).50 Comparisons of the prevalence of high-risk HPV types between military and civilian women are difficult, given the variation in types included within this category15, 48(Table 3B).
Both the DOD and Department of Veterans Affairs (VA) recommend cervical cancer screening for sexually active women with a cervix.51 In 2007, the DOD expanded women's cancer screening from Papanicolaou testing to cervical cancer screening to ensure coverage of current screening mechanisms, including HPV typing, for TRICARE (the DOD healthcare plan) beneficiaries.52 Rates of cervical cancer screening among active duty servicewomen have increased over time from 78% of women receiving screening within 12 months of deployment in 2003 to 90% receiving screening in 2005.53,54 In a large survey of active duty personnel conducted by the DOD in 2005, 97% of military women reported receiving cervical cancer screening within the past 3 years.17 High rates of cervical cancer screening have also been reported among TRICARE Prime beneficiaries, of whom 92% received screening within the past 3 years.55 This rate of cervical cancer screening was higher than among the general population of U.S. women.55 (Table 4A).
In addition to enhanced cervical cancer screening, administration of the HPV vaccine to appropriate individuals may also minimize the burden of HPV-related diseases among those in the military. The HPV vaccine is a TRICARE covered benefit,56 yet a 2011 study conducted at a Naval medical center found that only 16% of active duty women completed the three-vaccination series compared to 43% of dependent daughters and 21% of dependent spouses.57 Some active duty women may have deployed or relocated and completed the vaccination series at other facilities, yet it is still likely that the vaccination rate could be improved. Further studies on the rate of HPV vaccination among active duty servicewomen are needed (Table 4B).
In comparison to active duty servicewomen, little is known about the sexual risk-taking behaviors among female veterans. The prevalence of high-risk behaviors, including having multiple concurrent sexual partners and unintended sex after substance use, appears to decrease after women leave military service.27 Even with a reduction in these behaviors, however, female veterans may still be at risk. In a survey of 999 female veterans, 28% reported that their sexual partner had concurrent partners, and 17% reported having unintended sex after drinking alcohol or using drugs27 (Table 5). It is unknown if these high-risk sexual practices translate into high rates of STIs among women veterans.
There is a paucity of literature on the prevalence of cervical dysplasia and HPV infection within the military veteran population, but evidence suggests that the burden of these genital tract diseases are greater among these women compared to U.S. women on the whole. In a study evaluating the relationship between sexual assault and cervical dysplasia conducted among female veterans who were enrolled in VA care, 16% of women had one or more abnormal Pap tests within the past 5 years.27 Among those with an abnormal screening test, 48% were low-grade or high-grade SIL or carcinoma in situ.27 Victims of lifetime sexual assault were more likely than women without this history to have an abnormal Pap test.27 Furthermore, women who reported military sexual assault were also more likely to self-report infection with HPV compared to those who did not experience sexual assault while in the military27 (Table 5).
Regarding cervical cancer screening, evaluation of 144 VA medical centers revealed an average national screening rate of 90% among women veterans.58 Screening rates were higher in clinics with a greater proportion of female patients and when quality improvement programs were implemented58 (Table 5). Despite VA recommendations for routine cervical cancer screening, a qualitative study of female veterans found that although most women received cervical cancer screening at the VA, some were not aware that Pap tests were performed at VA medical centers.59 It is unknown if female veterans who are eligible for HPV vaccination receive this service.
Several studies among groups of U.S. military women suggest that this population may be at high risk for STIs and HPV-related disease. This review of the available literature reveals gaps that should be investigated as part of efforts to improve the reproductive health of U.S. military women. Most data on high-risk behaviors and STIs in military women comes from studies of new recruits or those who are early in their military careers. It is unknown if the military environment leads to high-risk sexual practices or if those who join the military are more likely to engage in high-risk behaviors because of demographic factors that are independent of their military status. Furthermore, there are limited data on the prevalence of high-risk sexual practices that can cause STIs and cervical dysplasia in older servicewomen and veterans. Research investigating the true risk factors for STIs and cervical dysplasia among military women are needed.
Detection of chlamydia may be higher among servicewomen compared to the general population because military policy dictates that all female recruits, not just those seeking screening, be tested,60 but direct comparison of STI rates between military and civilian women who seek screening are unavailable. Although routine STI screening occurs for female military recruits, Reserve and National Guard members who can seek care outside of military treatment facilities may also be at high risk but may not be screened. Female veterans may also have similar risk factors for STI acquisition, but prevalence of infection and rates of screening are unknown in this population. Evaluation of STI prevalence in active duty servicewomen, Reserve and National Guard members, and female veterans compared to civilian women are needed to determine if servicewomen are a truly high-risk group that could benefit from targeted interventions.
Sexual assault during military service may place servicewomen at risk for STIs, including HPV infection, and cervical dysplasia, but further research evaluating these relationships is necessary. The American College of Obstetricians and Gynecologists recommends immediate availability of prophylaxis against STIs for victims of sexual assault.61 But servicewomen who are victims of sexual assault are unlikely to report trauma. In a study of women veterans, only 26% who were raped during military service reported the assault to a military official, and 31% sought medical attention.62 Among those who seek care, it is unknown how many get screened, test positive, or receive prophylactic medications for STIs. Only one study has evaluated the relationship between military sexual trauma and cervical dysplasia.27 Cervical cancer screening programs targeted to victims of military sexual assault may be warranted, but this association needs to be evaluated in a variety of veteran populations.
Cervical cancer screening rates are high among both active duty and veteran women. However, the available literature suggests that rates of cervical dysplasia may be higher for military women compared to those in the general population. Costs associated with evaluation and treatment of abnormal Pap tests may be averted with greater implementation of the HPV vaccine in eligible military women. Although the HPV vaccination is covered by TRICARE and available on the VA formularly,56, 63 limited data show that few military women use this service. Additionally, among those who receive HPV vaccination, it is unknown how many go on to develop cervical dysplasia, given that not all high-risk HPV types are covered in the vaccine.64 Greater collaboration between DOD and VA medical facilities will allow for a unique opportunity to follow vaccinated women over time to assess disease outcomes.
The population of active duty and veteran women is increasing. These women may seek healthcare services from a variety of sources, including military facilities, VA medical centers, and civilian physicians. Thus, all healthcare providers need to understand the reproductive health issues of this population. Active duty servicewomen may be at higher risk for STIs, including HPV-related diseases, than civilian women. Female veterans may share the same risk factors for these diseases as active duty servicewomen, yet little is known about the prevalence of STIs among female veterans. To adequately address the healthcare needs of this growing population, further research into their unique reproductive health issues is necessary.
The project described was supported by award number K12HD050108 from the Office of the Director, National Institutes of Health, and the Eunice Kennedy Shriver National Institute of Child Health & Human Development. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Eunice Kennedy Shriver National Institute of Children Health & Human Development of the National Institutes of Health.
The authors have no conflicts of interest to report.