Health Related Behavior Study 2018 – Sexual Health & Behavior Within the Active Personnel

The Health-Related Behavior Survey (HRBS) is the US Department of Defense’s (DoD) primary survey of the health, health behaviors and well-being of military personnel. The HRBS, which has been conducted regularly for more than 30 years, covers areas that may affect military readiness or the ability to meet the demands of military life.

The Department of Defense commissioned the RAND Corporation to review and conduct the 2018 HRBS survey for active and reserve military personnel. This report discusses the results of the active component.

Results related to sexual behavior and health are discussed in this report. Some results are compared to the Healthy People 2020 (HP2020) goals for the U.S. population set by the U.S. Department of Health and Human Services. Because the military population is significantly different from the general population (for example, soldiers are more likely to be young and male than the general population), these comparisons are presented for comparison purposes only.

Outcomes of risky Sexual Behavior

Of all HRBS respondents, 19.3% (confidence interval [CI]: 18.3-20.4) reported having had more than one sexual partner in the past 12 months. In addition, 34.9% (CI 33.7-36.0) reported having sex with a new partner in the past 12 months without a condom. Navy respondents were more likely to report having sex with a new partner without a condom than respondents from any other service.

The HRBS survey found that 3.4% (CI 2.9-3.8) of the active population reported a sexually transmitted infection (STI) in the past 12 months. Although there was no significant difference in the proportion reporting STIs between services, there was a significant difference in the proportion of women (7.0% CI 5.8-8.1) and men (2.7% CI 2.2-3.2) reporting a single STI.

In addition, regression analyses of the 2015 HRBS and 2018 HRBS results showed a significant increase in the proportion of respondents who reported a STI in the past 12 months.

In the HRBS, high-risk service members at high risk for human immunodeficiency virus (HIV) infection were defined as men who had sex with one or more men in the past 12 months, service members who had engaged in vaginal or anal intercourse with more than one partner in the past 12 months, and service members who had a history of STIs in the past 12 months. The study found that 21.8% (CI 20.7-22.9) of respondents were at high risk of HIV infection.

Of all respondents, 2.9% (CI 2.5-3.3) reported having caused or had an unintended pregnancy in the past year. Women (5.5% CI 4.4-6.5) reported this more often than men (2.4% CI 1.9-2.9). This difference is probably due to the lack of information on unintended pregnancy among men. The proportion of military women reporting unintended pregnancy was slightly higher than the proportion of US women of childbearing age (4.5%, CI 4.1-4.9).

Use of Contraceptives

In 2016, the Department of Defense issued a memorandum (DHA-IPM 16-003) establishing comprehensive standards for contraceptive methods and contraceptive counseling. These standards adopt the Centers for Disease Control and Prevention (CDC) practice recommendations as guidelines for military clinical practice.

The HRBS survey focused on military personnel’s use of contraception in the past 12 months, when they had last had vaginal intercourse, and when they had experienced or caused an unintended pregnancy.

Condom and contraceptive pill use were the most common methods used by HRBS respondents. Long-acting contraceptive methods, such as the intrauterine device (IUD), were associated with significantly lower rates of unintended pregnancy.

Long-acting methods are more effective partly because they do not require the user to remember or use them correctly, as other methods do. The most commonly used long-acting method is the intrauterine contraceptive device.

Contraceptive method used during the last vaginal intercourse in the last 12 months

Highly effective methods
  • Male sterilisation (vasectomy) 7.5% (CI: 7.0-7.9).
  • IUD 9.9% (CI: 9.2-10.6)
  • Female sterilisation (e.g. tubal ligation, hysterectomy) 3.9% (CI 3.5-4.3).
  • Contraceptive implant (e.g. Implanon) 6.0% (CI 5.4-6.6).

Other methods
  • Condom 23.8% (CI 22.7-24.9)
  • Contraceptive pills 20.3% (CI 19.3-21.3)
  • Contraceptive pill, patch, ring or film 6.2% (CI 5.5-6.9).
  • Other method 4.8% (CI 4.3-5.3)

No contraceptive method or not used
  • Did not use any contraceptive method 16.8% (CI: 15.9-17.7).
  • Did not have vaginal contraception in the past 12 months 14.3% (CI 13.3-15.3).
  • I/ my partner tried to get pregnant 6.9% (CI 6.3-7.4)
  • I/ my partner was already pregnant 4.1% (CI 3.6-4.6).

The HP2020 target is that among women aged 15-44 years at risk of unintended pregnancy, 91.6% of those who used (or whose partner used) contraception at last intercourse would have used (or whose partner used) contraception.

The most recent civilian estimate available, based on data from the National Survey on Family Growth 2015-2017, is 79.6 percent (CI: 76.7-82.2). The HRBS survey found that 77.0 percent (CI: 75.0-79.1) of women aged 17-44 who were at risk of unintended pregnancy used contraception during their last vaginal intercourse.

The HP2020 target is that 69.3% of women aged 20-44 years would use a very or moderately effective method of contraception (sterilisation or contraceptive implant, contraceptive coil, contraceptive pill, injection, patch or ring, or diaphragm).

Data from the National Household Survey show that between 2015 and 2017, 60.2% (CI: 57.4-63.0) of all US women aged 20-44 who were not already pregnant and were not trying to conceive used an effective or moderately effective method of contraception. The HRBS study found that 65.0% (CI 62.8-67.2) of military women aged 20-44 years used such a method during their last vaginal intercourse in the past 12 months.

Operation-related unintended pregnancy, contraceptive availability and contraceptive counseling

Unintended pregnancy during deployment causes problems and operational difficulties for servicewomen that can threaten troop capability and readiness. The 2016 National Defense Authorization Act requires that military women receive comprehensive counseling on all contraceptive methods prior to deployment and at pre-deployment health screenings.

The 2017 National Defense Authorization Act required data on service members’ experiences with access to family planning services and counseling. The MoD also requires contraceptive counselling to be provided at the annual health check and at pre-deployment and post-deployment medical visits.

According to the HRBS, 0.08% (CI: 0.01-0.15) of service members had an unintended pregnancy during deployment in the previous year. Overall, 39% of women (CI: 34.7-43.4) and 14.5% of men (CI: 12.7-16.3) reported having received contraceptive counselling before deployment.

Before deployment, 86.4% (CI 82.1 to 90.7) of women and 13.5% (CI 8.7 to 18.3) of men reported that they were able to obtain or renew their preferred method of contraception. At the time of the survey, 77.7% (CI 71.3-84.1) of women and 19.0% (CI 12.2-25.7) of men reported being able to obtain or renew their preferred method of contraception.

HIV testing

The CDC recommends that people at risk be tested annually for HIV and recommends that men who have sex with men be tested every three to six months. The Department of Defense requires HIV testing at least every two years, and to be eligible for service, a person must have had an HIV test result within the past 24 months.

According to the HRBS, 75.8% (CI 74.7-76.9) of military personnel reported having been tested for HIV in the past 12 months and 38.3% (CI 37.1-39.4) in the past six months. Among personnel at high risk of HIV, 81.2% (CI 78.9-83.5) had been tested in the past 12 months.

Among men who reported having sex with men, 78.6% (CI 71.0-86.2) reported being tested for HIV in the past 12 months and 50.7% (CI 42.1-59.4) reported being tested in the past six months. The HP2020 target is for at least 68.4% of men who have sex with men to be tested for HIV annually.

Summary and Suggesions for Policy

A significant proportion of armed forces personnel engage in a range of sexual risk behaviours, including sex with multiple partners and, in particular, sex with a new partner without a condom. In addition, the HRBS shows that the prevalence of STIs has increased significantly in recent years. The Ministry of Defence and the Coast Guard should ensure that conscripts are provided with condoms at all locations free of charge or at a reduced price.

The results of school-based condom programmes show that these programmes increase condom use and reduce the incidence of STIs without encouraging sexual activity or increasing the number of sexual partners.

The Department of Defense and the Coast Guard should also consider regular STD screening, especially for women. Women in the service are much more likely than men to report STDs in the past 12 months, and there is a link between untreated chlamydia and female infertility.

The Department of Defense and the Coast Guard should consider expanding their efforts to provide contraceptive counseling to men. According to the National Family Planning Survey, 60% of men could benefit from planning services, and men aged 20-29 have the greatest need, but only 10% of them receive contraceptive counseling [3].3] These strategies include counseling men on condom use and how they can help their partners use other methods.

The Ministry of Defence and the Coast Guard should also work to increase the consistent and effective use of contraception. The MoD’s new contraceptive guidelines state that IUDs and implants should be considered as the primary method of contraception.

However, service providers and military personnel may need more education and awareness of the benefits of more effective contraceptive methods, and recognition that these methods may not be suitable for all women.

In particular, efforts need to be made to increase the proportion of personnel who receive contraceptive counselling prior to deployment. While we cannot know for sure why many military personnel do not report not having received pre-deployment contraceptive counseling, it is possible that these personnel and their service providers perceive counseling as less relevant to their situation.

Training activities should clarify that guidance on contraceptive counseling provided by soldiers applies to all personnel, including those who are not currently sexually active or who do not plan to become sexually active during deployment, those who identify as lesbian, gay or bisexual, and those who plan to have children in the near future.

Sexual activity can be unplanned, hormonal contraceptives can be used for non-contraceptive purposes, and long-acting contraceptive methods such as IUDs and implants are reversible. The Department of Defense and the Coast Guard could increase the annual HIV testing of at-risk individuals by improving screening at annual check-ups.

Although the current PHA form asks relevant questions, it is unclear whether information on different risk factors is combined to identify those in the highest risk category or whether certain risks (e.g., men who have sex with men) or combinations of risks should be routinely tested more frequently (annually or semi-annually) for HIV.


RAND conducted the 2018 HRBS survey among active duty and reserve military personnel in the US Air Force, Army, Navy, Marine Corps, and Coast Guard from October 2018 to March 2019. The 2018 HRBS survey was a confidential online survey that allowed researchers to send reminders to non-respondents and reduce survey burden by linking responses to administrative records.

The sample was selected using stratified random sampling by grade, salary level and gender. The overall weighted response rate for the survey was 9.6%, giving a final analytical sample of 17 166 responses. Missing data were handled using imputation, a statistical procedure where available data are used to estimate missing values.

To represent the active population, RAND researchers weighted responses to account for the overrepresentation of military personnel in certain sections. Point estimates and 95% CIs are presented in this research report.

RAND researchers controlled for differences in each outcome between key factor levels or subgroups – branch of service, grade, gender, race/ethnicity, and age group – using a two-step procedure based on the Rao-Scott chi-square test for overall differences between individual factor levels, and if the overall test was statistically significant, a two-sample t-test for all possible pairwise comparisons between factor levels (e.g. men vs. women).

Readers interested in these differences should refer to the full final report of the 2018 active component of the HRBS. This report is one of eight in the active component; this report and six of the other seven reports all correspond to different chapters in the full report, with the eighth report providing an overview of all findings and policy implications. A similar series of eight reports discusses the results of the reserve component.


The response rate to the survey is considered low. Although a low response rate does not automatically mean that the survey data are biased, it does increase the likelihood of bias.

As with any self-report survey, social desirability bias is possible, especially for sensitive questions and topics. For some groups representing a small percentage of the total military population, survey estimates may be inaccurate and should be interpreted with caution.

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