Skip to main content

Military Health System

Test of Sitewide Banner

This is a test of the sitewide banner capability. In the case of an emergency, site visitors would be able to visit the news page for addition information.

Musculoskeletal Injuries During U.S. Air Force Special Warfare Training Assessment and Selection, Fiscal Years 2019–2021.

Image of 01_Musculoskeletal Injuries. U.S. Air Force Capt. Hopkins, 351st Special Warfare Training Squadron, Instructor Flight commander and Chief Combat Rescue Officer (CRO) instructor, conducts a military free fall equipment jump from a DHC-4 Caribou aircraft in Coolidge, Arizona, July 17, 2021. Hopkins is recognized as the 2020 USAF Special Warfare Instructor Company Grade Officer of the Year for his outstanding achievement from January 1 to December 31, 2020.


From the inception of the Special Warfare Training Wing in fiscal year 2019 through 2021, 753 male, enlisted candidates attempted at least 1 Assessment and Selection and did not self-eliminate (i.e., quit). Candidates were on aver­age 23 years of age. During candidates’ first attempt, 356 (47.3%) individ­uals experienced a musculoskeletal (MSK) injury. Among the injuries, the most frequent type was nonspecific (n=334/356; 93.8%), and the most com­mon anatomic region of injury was the lower extremity (n=255/356; 71.6%). When included in a multivariable model, older age, slower run times on ini­tial fitness tests, and prior nonspecific injury were associated with both any injury and specifically lower extremity MSK injury.

What are the new findings?

During Assessment and Selection, 356 (47.3%) of candidates suffered an MSK injury. The most frequent type was nonspecific (n=334/356; 93.8%) and the most common anatomic region of injury was the lower extremity (n=255/356;
71.6%). Older age, slower run times, and prior nonspecific injury were associated with injury during the course.

What is the impact on readiness and force health protection?

MSK injuries are costly and continue to be the leading cause of medical visits and disability in the U.S. military and are more prevalent in the special operations community than in conventional military forces. Identifying predictors of injury in this population can inform clinicians and staff regarding the provision of prevention and rehabilitative strategies to reduce this risk.


Musculoskeletal (MSK) injuries are costly and the leading cause of medical visits and disability in the U.S. military.1,2 Within training envi­ronments, MSK injuries may lead to a loss of training, deferment to a future class, or voluntary disenrollment from a training pipeline, all of which are impediments to maintaining full levels of manpower and resources for the Department of Defense. Additionally, injuries sustained during training often lead to chronic conditions or impairments at a later time during a warf­ighter’s career.Previous studies have found that spe­cial operations forces experience higher MSK injury rates than conventional forces,4 and more so in training environ­ments.5 Although previous investigations have studied MSK injury rates in samples of Air Force (AF) special operators,4,6 to date, there are no studies that have explic­itly characterized the incidence of MSK injuries in the AF Special Warfare Training Wing (SWTW) pipeline. 

The AF SWTW was established in fis­cal year 2019 to assess, select, and train individuals to become one of 4 AF Special Warfare (AFSPECWAR) specialties: Tacti­cal Air Control Party (TACP), Pararescue, Combat Control, and Special Reconnais­sance. With the exception of TACP, each of these specialties require a candidate to successfully complete an arduous 16-day Assessment & Selection (A&S) course. Due to the nature of this assessment process, MSK injuries are common. However, no studies have reported the incidence of MSK injuries during A&S. Thus, the purpose of this study was to report the incidence of MSK injury during the 16-day SWTW A&S; and identify factors that were associ­ated with experiencing an MSK injury dur­ing this period.Methods

The cohort included enlisted AFSPEC­WAR candidates who first attempted A&S during fiscal years 2019–2021 and did not voluntarily disenroll (i.e., quit). Officer candidates were excluded from the analysis due to differences in their previous train­ing prior to A&S. Female candidates were excluded due to the small number of candi­dates (n=5), which precluded comparisons by sex. Data for analysis were routinely collected throughout the pipeline lead­ing up to the start of A&S (Figure 1). The Armed Services Vocational Aptitude Bat­tery (ASVAB)7 was administered before the candidates entered Basic Military Training (BMT). Results from baseline fitness tests and body composition factors were col­lected at the start of the Special Warfare Candidate Course (SWCC). The Intelli­gence Quotient (IQ) test was administered at the start of A&S. 

Data regarding MSK injuries were extracted from the Military Health System (MHS) Management Analysis and Report­ing Tool. The direct care outpatient system was searched for encounters within the stated timeframes for the cohort. The 10th Revision of the International Classification of Disease (Clinical Modification) codes were categorized according to a matrix that assigned an injury type and region to each injury using a taxonomy adapted from a previously published work.3,8 Briefly, the matrix broadened the inclusion of non-specific, overuse, and other MSK condi­tions that can also impact completion of training. For the coding of prior MSK injury, the timeframe of 6-months prior to starting A&S was selected to align with the timeframe of a candidate entering BMT, at which point relevant healthcare records are collected within the MHS.Covariates were selected for analysis based on 2 specific rationales; (1) explan­atory covariates including baseline fitness, body composition, and prior injury status that are known from the literature to have an association with risk of injury, and (2) exploratory covariates including anthro­pometric measurements, cognitive factors, and age that are routinely collected by the SWTW and discussed internally as poten­tially related to injury risk.

The injury surveillance period included the 16-day course as well as an additional 7 days following course termination, when students were permitted to rest with little to no formal training conducted. The sur­veillance period was extended in this way because many candidates will not report their injuries until the training concludes. In addition, providers are often unable to document injuries in the electronic medi­cal record system until the course finishes. Chi-square tests and independent samples t-tests were used for bivariate testing of cat­egorical and continuous factors, respec­tively, for differences between candidates with and without MSK injury during A&S. Where appropriate, the Mann-Whitney U, and Fisher’s exact tests were also employed. Binary logistic regression was used to build multivariable models to identify factors associated with MSK injury during A&S. In addition, binary logistic regression was also employed to identify factors associ­ated with lower extremity MSK injury specifically, the most common anatomic site of injury. For multivariable modeling, complete-case analysis was employed. The TRIPOD checklist was followed for model development only (i.e., not validation).9

The presented final binary logistic regres­sion models were exploratory in nature and future validation will be necessary. SAS ver­sion 9.4 (SAS Institute, Cary, NC) was used for all statistical analyses. Odds ratios (ORs) adjusted ORs (AORs), and their associated confidence intervals (CI) are reported with a threshold of p<.05 for univariate signifi­cance and a threshold of p<.10 was used to determine retention of variables in the logistic regression models. The final logistic regression model was selected that obtained optimal goodness of fit and area under the receiver operating curve.


Overall, 753 male enlisted candidates attempted A&S at least once and did not self-eliminate during fiscal years 2019 (4 classes), 2020 (5 classes), or 2021 (6 classes) (Figure 2). Candidates were, on average, 23 years of age at the start of their first A&S attempt. During candidates’ first A&S attempt, 356 (47.3%) experienced an MSK injury; of those can­didates, the most frequent injury type was nonspecific (n=334/356; 93.8%) (Figure 3), and the most common anatomic region of injury was the lower extremity (n=255/356; 71.6%) (Figure 4). 

Any type of MSK injury

Bivariate analyses revealed that initial fitness, age, BMI, and prior MSK injury were statistically significantly associated with injury during candidates' first A&S attempt (Table 1). The only baseline fit­ness measure significantly associated with injury during A&S was slower 1.5 mile run times. Body fat mass, lean body mass, dry lean mass, percent body fat, and skeletal muscle mass, were not significantly higher for candidates who were injured, compared with those who were not injured. Slightly more than one-half of the candidates (n=393; 52.2%) had suffered any prior MSK injury type, and a significant proportion of these candidates also suffered injury during A&S (64.0% vs 41.6%; p<.001). More spe­cifically, prior nonspecific, nerve, sprain or joint damage, strain or tear, and systemic or genetic MSK conditions were all associated with a higher frequency of injury during A&S. Injuries that occurred at all anatomic sites other than the torso were associated with a higher frequency of any type of injury during A&S.

The average age of candidates injured during A&S was significantly higher (24.2 years, SD=4.1) compared with those who were not injured (23.0 years, SD=3.8). Other tested cognitive factors, including highest academic level, overall IQ, and ASVAB test scores were not significantly associated with injury during A&S in bivar­iate analyses.Multivariable analysis

In an adjusted binary logistic regres­sion model, factors that were retained as associated with injury during A&S included age at A&S start (AOR=1.09; 95% CI: 1.04–1.14; p<.001), 1.5 mile run time on initial fitness test (AOR=1.53; 95% CI: 1.15–2.05; p=.004), and prior nonspe­cific injury (AOR=2.25; 95% CI: 1.64–3.10; p<.001) (Table 2). 
In an adjusted  model, factors that were retained as associated with lower extrem­ity injury during A&S included age at A&S start (AOR=1.05; 95% CI: 1.01–1.10; p=.018), 1.5 mile run time on initial fitness test (AOR=1.41; 95% CI: 1.05–1.90; p=.023), and prior nonspecific injury (AOR=1.91; 95% CI: 1.37–2.67; p<.001) (Table 3).

Editorial Comment

The purpose of this study was to report the incidence of MSK injuries in a 16-day rigorous SWTW A&S, and to identify fac­tors associated with suffering an MSK injury. This is the first characterization of MSK injury in a SWTW A&S population, finding 47.3% of candidates suffered an MSK injury, with the most frequent type as nonspecific (93.8%; of those injured). Knapik et al pre­viously described medical encounters dur­ing a U.S. Army Special Forces A&S course, reporting 38% of the candidates experi­enced one or more injuries during the 19-20 day period.10 The high percentage of injury among both cohorts is an indication of the rigorous requirements incurred by trainees in short periods of times under extremely challenging circumstances.

The lower extremity was identified as the most common anatomic region of injury during A&S (71.6%; of those injured). This finding is consistent with Lovalekar et al, who also reported lower extremity MSK injury as the most common region in Navy Sea, Air, and Land (SEAL) Qualification Training Students.11 However, both find­ings should be interpreted with caution, as these values may be underestimates due to potential under-reporting.12

When put into a multivariable model, older age, slower run times on initial fitness tests and prior nonspecific injury increased the likelihood of any musculoskeletal injury and, more specifically, lower extremity MSK injury. Although BMI was significant on the univariate analysis, the variable did not meet the criteria for retention in the final adjusted model. These findings are similar to previ­ous studies of similar populations that have found low levels of physical fitness, slower run time or history of a previous injury13–15 were all associated with sustaining MSK injury. Age, poor muscular endurance, and slower run times have also been observed to be reliable indicators of future acute injuries in U.S. Army Infantry, Armor, and Cavalry basic trainees during initial entry training (IET),16 but only performance deficits in running tests were correlated with ‘overuse’ MSK injuries in their cohort. Several addi­tional observations of military IET samples have reported similarities in MSK injury risk associated with poor aerobic capacity test performances, which does indicate a distinct and historical association between aerobic fitness and MSK incidence early in military service.17–19 

A novel aspect of this manuscript ana­lyzed IQ and ASVAB scores for association with MSK injury. These potential covari­ates were selected a priori based on litera­ture demonstrating relationships between neurocognition, biomechanics20 and early screening21 to detect MSK injury. Addi­tionally, literature documents components of ASVAB scores as a reliable predictor for graduation in an Army course,22 supporting the current study hypothesis to investigate an association between ASVAB scores and MSK injury during A&S. However, no sig­nificant relationship was found for either IQ or ASVAB scores.

There are inherent limitations to the collected data and analysis. First, this work is retrospective, and as such is subject to selec­tion bias. Additionally, there was no delin­eation between injuries and training loss for the candidates, and therefore the results should be interpreted with caution. Also, the vast majority of candidates who voluntarily disenrolled during A&S did so within the first 2 days of A&S (internal data), and since this would potentially significantly impact the injury exposure, these candidates were excluded from analysis. However, as some of these candidates may have disenrolled due to an unspecified injury, this would impact the findings of this study.

Finally, all candidates were cleared med­ically to transition from BMT to SWCC, and again from SWCC to A&S. It is assumed at the start of SWCC and A&S that MSK inju­ries have been resolved, and candidates have a ‘clean bill of health’. However, due to the inherent nature of MSK injuries, challenges with diagnosis, and candidates’ propen­sity to not report injuries that could delay the completion of their training, it is pos­sible that some MSK injuries prior to A&S are indistinguishable from new injuries dur­ing A&S. Regardless, increased surveillance of candidates who had prior injuries is still warranted for injury prevention during A&S whether they are new or persistent. Future work is planned to examine the detailed timing and severity of MSK injuries, as well as elimination rates and types, throughout the training pipeline.

In conclusion, MSK injuries continue to be costly and the leading cause of medi­cal visits and disability in the U.S. military and are more prevalent in the special opera­tions community than in conventional mili­tary forces. To increase the readiness and longevity of operators, continued efforts are required to reduce MSK injury risk. The findings from this project highlight the increased risk of MSK injury in this popu­lation and provide further evidence for the scientific community to continue to develop appropriate prevention, screening, and reha­bilitative strategies to reduce that risk and increase the health and readiness of mem­bers in the Special Warfare community.

Author Affiliations

Special Warfare Human Performance Squadron, Lackland Air Force Base, San Antonio TX.


 The views expressed are solely those of the authors and do not reflect the official policy or position of the U.S. Army, U.S. Navy, U.S. Air Force, the Department of Defense, or the U.S. Government.


The authors acknowl­edge Dr. William C Scott PhD for his contri­butions in data retrieval and management.


  1. Grimm PD, Mauntel TC, Potter BK. Combat and noncombat musculoskeletal injuries in the US military. Sports Med Arthrosc. 2019;27(3):84–91.
  2. Teyhen DS, Shaffer SW, Goffar SL, et al. Identi­fication of risk factors prospectively associated with musculoskeletal injury in a warrior athlete popula­tion. Sports Health. 2020;12(6):564–572.
  3. Molloy JM, Pendergrass TL, Lee IE, Chervak MC, Hauret KG, Rhon DI. Musculoskeletal injuries and United States Army readiness Part I: over­view of injuries and their strategic impact. Mil Med. 2020;185(9-10):e1461–e1471.
  4. Warha D, Webb T, Wells T. Illness and injury risk and healthcare utilization, United States Air Force battlefield airmen and security forces, 2000-2005. Mil Med. 2009;174(9):892–898.
  5. Stannard J, Fortington L. Musculoskeletal inju­ry in military Special Operations Forces: a system­atic review. BMJ Mil Health. 2021;167(4):255–265.
  6. Lovalekar M, Johnson CD, Eagle S, et al. Epi­demiology of musculoskeletal injuries among US Air Force Special Tactics Operators: an economic cost perspective. BMJ Open Sport Exerc Med. 2018;4(1): e000471.
  7. Cudeck R. A structural comparison of conven­tional and adaptive versions of the ASVAB. Multi­variate Behav Res. 1985;20(3):305–322.
  8. Hauschild V, Hauret K, Richardson M, Jones BH, Lee T. A Taxonomy of Injuries for Public Health Monitoring and Reporting. Army Public Health Command. 2018.
  9. Collins GS, Reitsma JB, Altman DG, Moons KGM. Transparent reporting of a multivariable prediction model for individual prognosis or diag­nosis (TRIPOD): the TRIPOD statement. BJOG. 2015;122(3):434–443.
  10. Knapik JJ, Farina EK, Ramirez CB, Pasiakos SM, McClung JP, Lieberman HR. Medical encoun­ters during the United States Army Special Forc­es Assessment and Selection Course. Mil Med. 2019;184(7-8):e337–e343.
  11. Lovalekar M, Perlsweig KA, Keenan KA, et al. Epidemiology of musculoskeletal injuries sustained by Naval Special Forces Operators and students. J Sci Med Sport. 2017;20 Suppl 4:S51–S56.
  12. Hotaling B, Theiss J, Cohen B, Wilburn K, Emberton J, Westrick R. Self-reported musculo­skeletal injury healthcare-seeking behaviors in US Air Force Special Warfare personnel. J Spec Oper Med. 2021;21(3):72–77.
  13. Kaufman KR, Brodine S, Shaffer R. Military training-related injuries: surveillance, research, and prevention. Am J Prev Med. 2000;18(3 Sup­pl):54–63.
  14. Shwayhat AF, Linenger JM, Hofherr LK, Sly­men DJ, Johnson CW. Profiles of exercise history and overuse injuries among United States Navy Sea, Air, and Land (SEAL) recruits. Am J Sports Med. 1994;22(6):835–840.
  15. Teyhen DS, Shaffer SW, Butler RJ, et al. What risk factors are associated with musculoskeletal in­jury in US Army Rangers? A Prospective prognostic study. Clin Orthop Relat Res. 2015;473(9):2948–2958.
  16. Sefton JM, Lohse KR, McAdam JS. Predic­tion of injuries and injury types in Army basic training, infantry, armor, and cavalry trainees Using a Common Fitness Screen. J Athl Train. 2016;51(11):849–857.
  17. Psaila M, Ranson C. Risk factors for lower leg, ankle and foot injuries during basic military train­ing in the Maltese Armed Forces. Phys Ther Sport. 2017;24:7–12.
  18. Wentz L, Liu PY, Haymes E, Ilich JZ. Females have a greater incidence of stress fractures than males in both military and athletic populations: a systemic review. Mil Med. 2011;176(4):420–430.
  19. Knapik J, Ang P, Reynolds K, Jones B. Physi­cal fitness, age, and injury incidence in infantry sol­diers. J Occup Med. 1993;35(6):598–603.
  20. Porter Ke’la, Quintana C, Hoch M. The relation­ship between neurocognitive function and biome­chanics: a critically appraised topic. J Sport Reha­bil. 2020;30(2):327–332.
  21. Berg Rice VJ, Connolly VL, Pritchard A, Bergeron A, Mays MZ. Effectiveness of a screen­ing tool to detect injuries during Army Health Care Specialist training. Work. 2007;29(3):177–188.
  22. Grant J, Vargas AL, Holcek RA, Watson CH, Grant JA, Kim FS. Is the ASVAB ST composite score a reliable predictor of first-attempt gradu­ation for the U.S. Army operating room specialist course? Mil Med. 2012;177(11):1352–1358.


FIGURE 1. Schematic of training pipeline through Assessment and Selection, and time points of data collection for analysis

 Candidate inclusion and exclusion criteria for analysis


Frequency of musculoskeletal injuries by type, fiscal years 2019–2021


Frequency of musculoskeletal injury by anatomic site, fiscal years 2019–2021

Baseline demographic, fitness, and cognitive factors, by musculoskeletal status, fiscal years 2019–2021

Multivariable assessment of predictors of any musculoskeletal injury during Assessment and Selection (n=665)

Multivariable assessment of predictors of lower extremity musculoskeletal injury during Assessment and Selection (n=665)

You also may be interested in...

Absolute and relative morbidity burdens attributable to various illnesses and injuries, active component, U.S. Armed Forces, 2018

Cover 1

In 2018, mental health disorders accounted for the largest proportions of the morbidity and healthcare burdens that affected the pediatric and younger adult beneficiary age groups. Among adults aged 45–64 years, musculoskeletal diseases accounted for the most morbidity and healthcare burdens, and among adults aged 65 years or older, cardiovascular diseases accounted for the most.

Absolute and relative morbidity burdens attributable to various illnesses and injuries, non-service member beneficiaries of the Military Health System, 2018

Cover 4

In 2018, mental health disorders accounted for the largest proportions of the morbidity and healthcare burdens that affected the pediatric and younger adult beneficiary age groups. Among adults aged 45–64 years, musculoskeletal diseases accounted for the most morbidity and health care burdens, and among adults aged 65 years or older, cardiovascular diseases accounted for the most.

Incidence, Timing, and Seasonal Patterns of Heat Illnesses During U.S. Army Basic Combat Training, 2014–2018

U.S. Marines participate in morning physical training during a field exercise at Marine Corps Base Camp Pendleton, California. (Photo Courtesy: U.S. Marine Corps)

Risk factors for heat illnesses (HIs) among new soldiers include exercise intensity, environmental conditions at the time of exercise, a high body mass index, and conducting initial entry training during hot and humid weather when recruits are not yet acclimated to physical exertion in heat. This study used data from the Defense Health Agency’s–Weather-Related Injury Repository to calculate rates and to describe the incidence, timing, and geographic distribution of HIs among soldiers during U.S. Army basic combat training (BCT). From 2014 through 2018, HI events occurred in 1,210 trainees during BCT, resulting in an overall rate of 3.6 per 10,000 BCT person-weeks (p-wks) (95% CI: 3.4–3.8). HI rates (cases per 10,000 BCT p-wks) varied among the 4 Army BCT sites: Fort Benning, GA (6.8); Fort Jackson, SC (4.4); Fort Sill, OK (1.8); and Fort Leonard Wood, MO (1.7). Although the highest rates ofHIs occurred at Fort Benning, recruits in all geographic areas were at risk. The highest rates of HI occurred during the peak training months of June through Sept., and over half of all HI cases affected soldiers during the first 3 weeks of BCT. Prevention of HI among BCT soldiers requires relevant training of both recruits and cadre as well as the implementation of effective preventive measures.

Update: Exertional Rhabdomyolysis, Active Component, U.S. Armed Forces, 2014–2018

U.S. Marines sprint uphill during a field training exercise at Marine Corps Air Station Miramar, California. to maintain contact with an aviation combat element, teaching and sustaining their proficiency in setting up and maintaining communication equipment.  (Photo Courtesy: U.S. Marine Corps)

Among active component service members in 2018, there were 545 incident diagnoses of rhabdomyolysis likely due to exertional rhabdomyolysis, for an unadjusted incidence rate of 42.0 cases per 100,000 person-years. Subgroup-specific rates in 2018 were highest among males, those less than 20 years old, Asian/Pacific Islander service members, Marine Corps and Army members, and those in combat-specific or “other/unknown” occupations. During 2014–2018, crude rates of exertional rhabdomyolysis increased steadily from 2014 through 2016 after which rates declined slightly in 2017 before increasing again in 2018. Compared to service members in other race/ethnicity groups, the overall rate of exertional rhabdomyolysis was highest among non-Hispanic blacks in every year except 2018. Overall and annual rates were highest among Marine Corps members, intermediate among those in the Army, and lowest among those in the Air Force and Navy. Most cases of exertional rhabdomyolysis were diagnosed at installations that support basic combat/recruit training or major ground combat units of the Army or the Marine Corps. Medical care providers should consider exertional rhabdomyolysis in the differential diagnosis when service members (particularly recruits) present with muscular pain or swelling, limited range of motion, or the excretion of dark urine (possibly due to myoglobinuria) after strenuous physical activity, particularly in hot, humid weather.

Update: Heat Illness, Active Component, U.S. Armed Forces, 2018

Drink water the day before and during physical activity or if heat is going to become a factor. (Photo Courtesy: U.S. Air Force)

In 2018, there were 578 incident diagnoses of heat stroke and 2,214 incident diagnoses of heat exhaustion among active component service members. The overall crude incidence rates of heat stroke and heat exhaustion diagnoses were 0.45 cases and 1.71 cases per 1,000 person-years, respectively. In 2018, subgroup-specific rates of incident heat stroke diagnoses were highest among males and service members less than 20 years old, Asian/Pacific Islanders, Marine Corps and Army members, recruit trainees, and those in combat-specific occupations. Subgroup-specific incidence rates of heat exhaustion diagnoses in 2018 were notably higher among service members less than 20 years old, Asian/Pacific Islanders, Army and Marine Corps members, recruit trainees, and service members in combat-specific occupations. During 2014–2018, a total of 325 heat illnesses were documented among service members in Iraq and Afghanistan; 8.6% (n=28) were diagnosed as heat stroke. Commanders, small unit leaders, training cadre, and supporting medical personnel must ensure that the military members whom they supervise and support are informed about the risks, preventive countermeasures, early signs and symptoms, and first-responder actions related to heat illnesses.

Update: Exertional Hyponatremia, Active Component, U.S. Armed Forces, 2003–2018

Drink water the day before and during physical activity or if heat is going to become a factor. (Photo Courtesy: U.S. Air Force)

From 2003 through 2018, there were 1,579 incident diagnoses of exertional hyponatremia among active component service members, for a crude overall incidence rate of 7.2 cases per 100,000 person-years (p-yrs). Compared to their respective counterparts, females, those less than 20 years old, and recruit trainees had higher overall incidence rates of exertional hyponatremia diagnoses. The overall incidence rate during the 16-year period was highest in the Marine Corps, intermediate in the Army and Air Force, and lowest in the Navy. Overall rates during the surveillance period were highest among Asian/Pacific Islander and non-Hispanic white service members and lowest among non-Hispanic black service members. Between 2003 and 2018, crude annual incidence rates of exertional hyponatremia peaked in 2010 (12.7 per 100,000 p-yrs) and then decreased to 5.3 cases per 100,000 p-yrs in 2013 before increasing in 2014 and 2015. The crude annual rate in 2018 (6.3 per 100,000 p-yrs) represented a decrease of 26.5% from 2015. Service members and their supervisors must be knowledgeable of the dangers of excessive water consumption and the prescribed limits for water intake during prolonged physical activity (e.g., field training exercises, personal fitness training, and recreational activities) in hot, humid weather.

Modeling Lyme Disease Host Animal Habitat Suitability, West Point, New York

A deer basks in the morning sun at Joint Base San Antonio-Fort Sam Houston, Texas.  (Photo Courtesy: U.S. Air Force)

As the most frequently reported vector-borne disease among active component U.S. service members, with an incidence rate of 16 cases per 100,000 person-years in 2011, Lyme disease poses both a challenge to health care providers in the Military Health System and a threat to military readiness. Spread through the bite of an infected blacklegged tick, infection with the bacterial cause of Lyme disease can have lasting effects that may lead to medical discharge from the military. The U.S. Military Academy at West Point is situated in a highly endemic area in New York State. To identify probable areas where West Point cadets as well as active duty service members stationed at West Point and their families might contract Lyme disease, this study used Geographic Information System mapping methods and remote sensing data to replicate an established spatial model to identify the likely habitat of a key host animal—the white-tailed deer.

Brief Report: Male Infertility, Active Component, U.S. Armed Forces, 2013–2017

Sperm is the male reproductive cell  Photo: iStock

Infertility, defined as the inability to achieve a successful pregnancy after 1 year or more of unprotected sexual intercourse or therapeutic donor insemination, affects approximately 15% of all couples. Male infertility is diagnosed when, after testing both partners, reproductive problems have been found in the male. A male factor contributes in part or whole to about 50% of cases of infertility. However, determining the true prevalence of male infertility remains elusive, as most estimates are derived from couples seeking assistive reproductive technology in tertiary care or referral centers, population-based surveys, or high-risk occupational cohorts, all of which are likely to underestimate the prevalence of the condition in the general U.S. population.

Sexually Transmitted Infections, Active Component, U.S. Armed Forces, 2010–2018

Neisseria gonorrhoeae Photo Courtesy of CDC: M Rein

This report summarizes incidence rates of the 5 most common sexually transmitted infections (STIs) among active component service members of the U.S. Armed Forces during 2010–2018. Infections with chlamydia were the most common, followed in decreasing order of frequency by infections with genital human papillomavirus (HPV), gonorrhea, genital herpes simplex virus (HSV), and syphilis. Compared to men, women had higher rates of all STIs except for syphilis. In general, compared to their respective counterparts, younger service members, non-Hispanic blacks, soldiers, and enlisted members had higher incidence rates of STIs. During the latter half of the surveillance period, the incidence of chlamydia and gonorrhea increased among both male and female service members. Rates of syphilis increased for male service members but remained relatively stable among female service members. In contrast, the incidence of genital HPV and HSV decreased among both male and female service members. Similarities to and differences from the findings of the last MSMR update on STIs are discussed.

Vasectomy and Vasectomy Reversals, Active Component, U.S. Armed Forces, 2000–2017

Sperm is the male reproductive cell  Photo: iStock

During 2000–2017, a total of 170,878 active component service members underwent a first-occurring vasectomy, for a crude overall incidence rate of 8.6 cases per 1,000 person-years (p-yrs). Among the men who underwent incident vasectomy, 2.2% had another vasectomy performed during the surveillance period. Compared to their respective counterparts, the overall rates of vasectomy were highest among service men aged 30–39 years, non-Hispanic whites, married men, and those in pilot/air crew occupations. Male Air Force members had the highest overall incidence of vasectomy and men in the Marine Corps, the lowest. Crude annual vasectomy rates among service men increased slightly between 2000 and 2017. The largest increases in rates over the 18-year period occurred among service men aged 35–49 years and among men working as pilots/air crew. Among those who underwent vasectomy, 1.8% also had at least 1 vasectomy reversal during the surveillance period. The likelihood of vasectomy reversal decreased with advancing age. Non-Hispanic black and Hispanic service men were more likely than those of other race/ethnicity groups to undergo vasectomy reversals.

Testosterone Replacement Therapy Use Among Active Component Service Men, 2017


This analysis summarizes the prevalence of testosterone replacement therapy (TRT) during 2017 among active component service men by demographic and military characteristics. This analysis also determines the percentage of those receiving TRT in 2017 who had an indication for receiving TRT using the 2018 American Urological Association (AUA) clinical practice guidelines. In 2017, 5,093 of 1,076,633 active component service men filled a prescription for TRT, for a period prevalence of 4.7 per 1,000 male service members. After adjustment for covariates, the prevalence of TRT use remained highest among Army members, senior enlisted members, warrant officers, non-Hispanic whites, American Indians/Alaska Natives, those in combat arms occupations, healthcare workers, those who were married, and those with other/unknown marital status. Among active component male service members who received TRT in 2017, only 44.5% met the 2018 AUA clinical practice guidelines for receiving TRT.

Update: Malaria, U.S. Armed Forces, 2018

Anopheles merus

Malaria infection remains an important health threat to U.S. service mem­bers who are located in endemic areas because of long-term duty assign­ments, participation in shorter-term contingency operations, or personal travel. In 2018, a total of 58 service members were diagnosed with or reported to have malaria. This represents a 65.7% increase from the 35 cases identi­fied in 2017. The relatively low numbers of cases during 2012–2018 mainly reflect decreases in cases acquired in Afghanistan, a reduction due largely to the progressive withdrawal of U.S. forces from that country. The percentage of cases of malaria caused by unspecified agents (63.8%; n=37) in 2018 was the highest during any given year of the surveillance period. The percent­age of cases identified as having been caused by Plasmodium vivax (10.3%; n=6) in 2018 was the lowest observed during the 10-year surveillance period. The percentage of malaria cases attributed to P. falciparum (25.9 %) in 2018 was similar to that observed in 2017 (25.7%), although the number of cases increased. Malaria was diagnosed at or reported from 31 different medical facilities in the U.S., Afghanistan, Italy, Germany, Djibouti, and Korea. Pro­viders of medical care to military members should be knowledgeable of and vigilant for clinical manifestations of malaria outside of endemic areas.

Update: Incidence of Glaucoma Diagnoses, Active Component, U.S. Armed Forces, 2013–2017


Glaucoma is an eye disease that involves progressive optic nerve damage and vision loss, leading to blindness if undetected or untreated. This report describes an analysis using the Defense Medical Surveillance System to identify all active component service members with an incident diagnosis of glaucoma during the period between 2013 and 2017. The analysis identified 37,718 incident cases of glaucoma and an overall incidence rate of 5.9 cases per 1,000 person-years (p-yrs). The majority of cases (97.6%) were diagnosed at an early stage as borderline glaucoma; of these borderline cases, 2.2% progressed to open-angle glaucoma during the study period. No incident cases of absolute glaucoma, or total blindness, were identified. Rates of glaucoma were higher among non-Hispanic black (11.0 per 1,000 p-yrs), Asian/Pacific Islander (9.5), and Hispanic (6.9) service members, compared with non-Hispanic white (4.0) service members. Rates among female service members (6.6 per 1,000 p-yrs) were higher than those among male service members (5.8). Between 2013 and 2017, incidence rates of glaucoma diagnoses increased by 75.4% among all service members.

Re-evaluation of the MSMR Case Definition for Incident Cases of Malaria

Anopheles merus

The MSMR has been publishing the results of surveillance studies of malaria since 1995. The standard MSMR case definition uses Medical Event Reports and records of hospitalizations in counting cases of malaria. This report summarizes the performance of the standard MSMR case definition in estimating incident cases of malaria from 2015 through 2017. Also explored was the potential surveillance value of including outpatient encounters with diagnoses of malaria or positive laboratory tests for malaria in the case definition. The study corroborated the relative accuracy of the MSMR case definition in estimating malaria incidence and provided the basis for updating the case definition in 2019 to include positive laboratory tests for malaria antigen within 30 days of an outpatient diagnosis.

Outbreak of Acute Respiratory Illness Associated with Adenovirus Type 4 at the U.S. Naval Academy, 2016

Malaria case definition

Human adenoviruses (HAdVs) are known to cause respiratory illness outbreaks at basic military training (BMT) sites. HAdV type-4 and -7 vaccines are routinely administered at enlisted BMT sites, but not at military academies. During Aug.–Sept. 2016, U.S. Naval Academy clinical staff noted an increase in students presenting with acute respiratory illness (ARI). An investigation was conducted to determine the extent and cause of the outbreak. During 22 Aug.–11 Sept. 2016, 652 clinic visits for ARI were identified using electronic health records. HAdV-4 was confirmed by real-time polymerase chain reaction assay in 18 out of 33 patient specimens collected and 1 additional HAdV case was detected from hospital records. Two HAdV-4 positive patients were treated for pneumonia including 1 hospitalized patient. Molecular analysis of 4 HAdV-4 isolates identified genome type 4a1, which is considered vaccine-preventable. Understanding the impact of HAdV in congregate settings other than enlisted BMT sites is necessary to inform discussions regarding future HAdV vaccine strategy.

Page 14 of 15 , showing items 196 - 210
First < ... 11 12 13 14 15 > Last 
Refine your search
Last Updated: November 02, 2022
Follow us on Instagram Follow us on LinkedIn Follow us on Facebook Follow us on Twitter Follow us on YouTube Sign up on GovDelivery