Postpartum long-acting reversible contraceptive use among active-duty, female US Army soldiers.

BACKGROUND: Postpartum use of long-acting reversible contraception has been found to be effective at increasing interpregnancy intervals, reducing unintended pregnancies, and optimizing health outcomes for mothers and babies. Among female active-duty military service members, reproductive planning may be particularly important, yet little is known about postpartum long-acting reversible contraceptive use among active-duty soldiers. OBJECTIVE: This study aimed to (1) quantify postpartum uptake of long-acting reversible contraception among active-duty female US Army soldiers and (2) identify demographic and military-specific characteristics associated with use. STUDY DESIGN: This retrospective cohort study used longitudinal data of all digitally recorded health encounters for active-duty US Army soldiers from 2014 to 2017. The servicewomen included in our analysis were aged 18 to 44 years with at least one delivery and a minimum of 4 months of total observed time postdelivery within the study period. We defined postpartum long-acting reversible contraception use as initiation of use within the delivery month or in the 3 calendar months following delivery and identified likely immediate postpartum initiation via the proxy of placement recorded during the same month as delivery. We then evaluated predictors of postpartum long-acting reversible contraception use with multivariable logistic regression. RESULTS: The inclusion criteria were met by 15,843 soldiers. Of those, 3162 (19.96%) initiated the use of long-acting reversible contraception in the month of or within the 3 months following delivery. Fewer than 5% of these women used immediate postpartum long-acting reversible contraception. Among women who initiated postpartum long-acting reversible contraceptive use, 1803 (57.0%) received an intrauterine device, 1328 (42.0%) received an etonogestrel implant, and 31 received both (0.98%). Soldiers of younger age, self-reported White race, and those who were married or previously married were more likely to initiate long-acting reversible contraception in the postpartum period. Race-stratified analyses showed that self-reported White women had the highest use rates overall. When compared with these women, the adjusted odds of postpartum use among self-reported Black and Asian or Pacific Islander women were 18% and 30% lower, respectively (both P<.001). There was also a trend of decreasing postpartum use with increasing age within each race group. Differences observed between age groups and race identities could partially be attributed to differential use of permanent contraception (sterilization), which was found to be significantly more prevalent among both women aged 30 years or older and among women who identified as Black. CONCLUSION: Among active-duty US Army servicewomen, 1 in 5 used postpartum long-acting reversible contraception, and fewer than 5% of these women used an immediate postpartum method. Within this population with universal healthcare coverage, we observed relatively low rates of use and significant differences in the uptake of effective postpartum long-acting contraceptive methods across self-reported race categories.

Physical Fitness in Relationship to Depression and Post-Traumatic Stress Disorder During Pregnancy Among U.S. Army Soldiers.

Background: Depression and post-traumatic stress disorder (PTSD) are prevalent in pregnancy, especially among military members. These conditions can lead to adverse birth outcomes, yet, there's a paucity of evidence for prevention strategies. Optimizing physical fitness is one understudied potential intervention. We explored associations between prepregnancy physical fitness and antenatal depression and PTSD in soldiers. Materials and Methods: This was a retrospective cohort study of active-duty U.S. Army soldiers with live births between 2011 and 2014, identified with diagnosis codes from inpatient and outpatient care. The exposure was each individual's mean Army physical fitness score from 10 to 24 months before childbirth. The primary outcome was a composite of active depression or PTSD during pregnancy, defined using the presence of a code within 10 months before childbirth. Demographic variables were compared across four quartiles of fitness scores. Multivariable logistic regression models were conducted adjusting for potential confounders selected a priori. A stratified analysis was conducted for depression and PTSD separately. Results: Among 4,583 eligible live births, 352 (7.7%) had active depression or PTSD during pregnancy. Soldiers with the highest fitness scores (Quartile 4) were less likely to have active depression or PTSD in pregnancy (Quartile 4 vs. Quartile 1 adjusted odds ratio 0.55, 95% confidence interval 0.39-0.79). Findings were similar in stratified analyses. Conclusion: In this cohort, the odds of active depression or PTSD during pregnancy were significantly reduced among soldiers with higher prepregnancy fitness scores. Optimizing physical fitness may be a useful tool to reduce mental health burden on pregnancy.

Incidence of Ankylosing Spondylitis Among Male and Female United States Army Personnel.

OBJECTIVE: Incidence rates of ankylosing spondylitis (AS) among males versus females are poorly understood. Results of prior research have been mixed, including findings of a 3:1 incidence ratio for males versus females, but with increasing AS rates among females. The objective was to estimate the incidence of AS among members of the US military. METHODS: We estimated the incidence of AS in a retrospective cohort study of diverse, working-age US military service members during March 2014 to June 2017 (n = 728,556) who underwent clinical practice guideline-directed screening for chronic back pain. Incident AS cases were identified using diagnostic codes from electronic medical and administrative records. RESULTS: In contrast to some prior studies, AS incidence was similar among males and females (incidence rate ratio 1.16, P = 0.23; adjusted odds ratio [OR] 0.79 [95% confidence interval (95% CI) 0.61-1.02]; P = 0.072). AS rates increased approximately monotonically with age. Consistent with prior research, the AS incidence rate was greater in the White population than in the Black population (adjusted OR 1.39 [95% CI 1.01-1.66]; P = 0.04). CONCLUSION: In this study population, the incidence of AS was similar for the sexes. Previous observations of male predominance have typically been derived from clinic populations that are less representative of the US race/ethnicity distribution and based on disease ascertainment tools that may have identified subjects later in their disease course. Our study population also differed in being subject to organized screenings for musculoskeletal symptoms. Our findings suggest that sex may not predict AS incidence in the US population.

Service discharges among US Army personnel with selected musculoskeletal and skin conditions: a retrospective cohort study.

OBJECTIVES: To determine the probability of discharge from military service among soldiers following an incident diagnosis of ankylosing spondylitis (AS), rheumatoid arthritis (RA), psoriasis or systemic lupus erythematous. METHODS: All soldiers on active duty in the US Army between January 2014 and June 2017 were included in a retrospective cohort analysis. Termination from service was ascertained using personnel records. Diagnostic codes were used to identify incident cases of the four musculoskeletal and skin diseases and, for comparison, diabetes mellitus (DM). Time to discharge was modelled using sex stratified multivariate survival analysis. RESULTS: The analysis included 657 417 individuals with a total of 1.2 million person-years of observation. An elevated risk of discharge was observed in association with each of the five chronic conditions studied. The increase in adjusted risk of discharge was highest among soldiers with AS (men, HR=2.5, 95% CI 2.1 to 3.0; women, HR=2.1, 95% CI 1.4 to 3.2) and with DM (men, HR=2.4, 95% CI 2.2 to 2.7; women, HR=2.2, 95% CI 1.8 to 2.5), followed by those with RA (men, HR=1.8, 95% CI 1.5 to 2.2; women, HR=1.8, 95% CI 1.4 to 2.4). CONCLUSIONS: Military discharges are consequential for the service and the service member. The doubling in risk of discharge for those with AS or RA was comparable to that for personnel with DM. Conditions that affect the spine and peripheral joints may often be incompatible with military readiness. Nevertheless, a substantial fraction of service members with these diagnoses continued in service.

Post-Traumatic Stress Disorder Among U.S. Army Drone Operators.

INTRODUCTION: Exposure to traumatic events could increase post-traumatic stress disorder (PTSD) risk among enlisted U.S. Army drone operators. Published research on PTSD risk in this population is unavailable.METHODS: We used a combined medical and administrative longitudinal dataset to examine adjusted associations between drone operator service among U.S. Army enlisted members and three PTSD indicators: whether screened via the PTSD Checklist - Civilian (PCL-C); PCL-C scores; and incident PTSD diagnoses. We compiled summary statistics for and conducted tests of differences in independent variable distributions when comparing drone operators and others. Two multivariable survival regression models and an ordinary least squares model were used to estimate adjusted associations.RESULTS: There were 1.68 million person-years of observed time in the study population (N = 678,548; drone operator N = 2856). Compared to other servicemembers, the adjusted likelihood of undergoing PTSD screening was 35% lower [95% confidence interval (CI) for the adjusted hazard ratio (aHR): 0.56-0.76]. Among subjects who took the PCL-C, scores did not differ significantly on the basis of drone operator service (adjusted change: -1.26 points; CI: -3.41-0.89). The adjusted hazard of receiving a PTSD diagnosis was 34% lower among drone operators (CI: 0.54-0.80).DISCUSSION: These findings provide reassurance that enlisted U.S. Army drone operators are not at increased risk of PTSD. Further research is needed in order to identify the mechanisms of the decreased PTSD risk observed, and whether other or longer-term mental health risks are present among those in this occupation.Nelson DA, Wilson M, Kurina LM. Post-traumatic stress disorder among U.S. Army drone operators. Aerosp Med Hum Perform. 2022; 93(7):562-570.

Health seeking behavior after the 2013-16 Ebola epidemic: Lassa fever as a metric of persistent changes in Kenema District, Sierra Leone.

BACKGROUND: The West African Ebola epidemic of 2013-2016 killed nearly 4,000 Sierra Leoneans and devastated health infrastructure across West Africa. Changes in health seeking behavior (HSB) during the outbreak resulted in dramatic underreporting and substantial declines in hospital presentations to public health facilities, resulting in an estimated tens of thousands of additional maternal, infant, and adult deaths per year. Sierra Leone's Kenema District, a major Ebola hotspot, is also endemic for Lassa fever (LF), another often-fatal hemorrhagic disease. Here we assess the impact of the West African Ebola epidemic on health seeking behaviors with respect to presentations to the Kenema Government Hospital (KGH) Lassa Ward, which serves as the primary health care referral center for suspected Lassa fever cases in the Eastern Province of Sierra Leone. METHODOLOGY/PRINCIPAL FINDINGS: Presentation frequencies for suspected Lassa fever presenting to KGH or one of its referral centers from 2011-2019 were analyzed to consider the potential impact of the West African Ebola epidemic on presentation patterns. There was a significant decline in suspected LF cases presenting to KGH following the epidemic, and a lower percentage of subjects were admitted to the KGH Lassa Ward following the epidemic. To assess general HSB, a questionnaire was developed and administered to 200 residents from 8 villages in Kenema District. Among 194 completed interviews, 151 (78%) of respondents stated they felt hospitals were safer post-epidemic with no significant differences noted among subjects according to religious background, age, gender, or education. However, 37 (19%) subjects reported decreased attendance at hospitals since the epidemic, which suggests that trust in the healthcare system has not fully rebounded. Cost was identified as a major deterrent to seeking healthcare. CONCLUSIONS/SIGNIFICANCE: Analysis of patient demographic data suggests that fewer individuals sought care for Lassa fever and other febrile illnesses in Kenema District after the West African Ebola epidemic. Re-establishing trust in health care services will require efforts beyond rebuilding infrastructure and require concerted efforts to rebuild the trust of local residents who may be wary of seeking healthcare post epidemic.

An investigation of sickle cell trait, body mass index, and fitness in relation to venous thromboembolism among African American adults.

BACKGROUND: The relationships of sickle cell trait (SCT), body mass index (BMI), and physical fitness to venous thromboembolism (VTE) in young adults have received little attention. OBJECTIVES: To test for associations among SCT, BMI, fitness, and VTE. PATIENTS/METHODS: We conducted a retrospective cohort study of 48,316 SCT-tested, African American individuals in the US Army during 2011-14. We used Cox proportional hazards models to compute adjusted hazards of deep vein thrombosis (DVT) and pulmonary embolism (PE) associated with selected factors. RESULTS: Incidence rates of DVT and PE were 1.09 and 0.91 cases per 1000 person-years, respectively. Adjusted hazard ratios (aHRs) for DVT for men and women with SCT were 0.9 (95% confidence interval [CI]: 0.4-2.0; P = .711) and 1.51 (CI: 0.7-3.2; P = .274), respectively. aHRs for PE for SCT+ men and women were 1.1 (CI: 0.5-2.4; P = .773) and 1.2 (CI: 0.5-3.1; P = .650), respectively. Low physical fitness was associated with DVT and PE in women (DVT aHR =3.1; CI: 1.4-6.5; P = .004; PE aHR =4.6; CI: 2.1-9.9; P < .001) and DVT in men (aHR =2.2; CI: 1.0-4.6; P = .048). Recent weight gain of 1 or more BMI points was associated with DVT in men (aHR =1.8; CI: 1.1-2.8; P = .017). CONCLUSIONS: We found no evidence of increased VTE risk associated with SCT in this population. However, lower fitness levels and BMI increases were so associated.

Incidence of Pelvic Floor Disorders in US Army Female Soldiers.

OBJECTIVE: To determine the incidence of pelvic floor disorders (PFD) among active-duty US Army female soldiers. MATERIALS AND METHODS: We studied 102,015 women for incident PFD using the Stanford Military Data Repository, which comprises medical, demographic and service-related information on all soldiers on active duty in the US Army during 2011-2014. Cox proportional hazards estimated adjusted associations with PFD diagnoses. In the adjusted models, military-specific characteristics and fitness were evaluated alongside known PFD predictors. RESULTS: Among 102,015 subjects at risk there was a cumulative incidence of 6.4% over a mean of 27 months (median 29, range 1-42). In adjusted models, obese soldiers were more likely to have a PFD compared to those of normal weight (hazard ratio [HR] 1.23, confidence interval [CI] 1.14-1.34, P <0.001) and those with recent weight gain were more likely to have a PFD compared to those without (HR 1.32, CI 1.24-1.40, P <0.05). Women with the lowest physical fitness scores were more likely to have a PFD (HR 1.14, CI 1.04-1.25) compared to those with the highest scores. CONCLUSION: Over a median follow-up time of 29 months, 1 in 15 women in this active-duty cohort was diagnosed with a PFD. Optimizing risk factors including body mass index and physical fitness may benefit the pelvic health of female soldiers, independent of age, children, and years of service.

Military Occupational Disability Risk Surveillance: A Retrospective Cohort Study of Modifiable Risk Factors.

INTRODUCTION: Occupational disability among military service members is an important target for preventive screening. The specific aim of this study was to quantify disability risk levels among soldiers with selected risk factors (body mass index extremes, poor or absent physical fitness scores, and tobacco and opioid use) and combinations thereof, suggesting priorities for preventive actions. MATERIALS AND METHODS: This was a retrospective cohort study of 607,006 active-duty soldiers who served in the U.S. Army during 2011-2014. Official medical and administrative data were combined to produce a person-month-based panel dataset with identifiers removed. The subjects were observed longitudinally for incident disability (termed medical nonreadiness) during 1,305,618 person-years at risk. We employed Weibull parametric survival regression models to determine the adjusted medical nonreadiness hazard for selected variables. We then computed individual adjusted risk scores and the population proportions affected by risk factors and combinations thereof in postregression analyses. The project was approved by the Stanford University's Institutional Review Board and underwent secondary review by the Human Research Protections Office of the Defense Health Agency. RESULTS: During the observed time, 81,571 (13.4%) of subjects were found medically not ready. High or low body mass index, low or missing physical fitness test scores, tobacco use, and the highest levels of opioid use were each associated with increased adjusted hazards of medical nonreadiness. The hazards increased substantially when multiple risk factors were present, albeit while affecting reduced population proportions. CONCLUSIONS: We identified marked disability hazard increases, especially in association with opioid use and high body mass index. These factors, in addition to tobacco use and low physical fitness, are potential early prevention targets for clinicians who screen military service members.

Stressful Life Changes and Their Relationship to Nutrition-Related Health Outcomes Among US Army Soldiers.

Stressful life changes may tax people's adaptive capacity. We sought to determine if and when experiences of stressful life changes were associated with increased odds of adverse nutrition-related health outcomes among US Army soldiers relative to those who did not experience the same stressful life change. An additional aim was to determine which stressful life changes had the greatest association with these outcomes and if there were gender differences in the magnitude of the associations. Stressful life changes studied included: changes in marital status, combat deployment or return from deployment, relocation, adding a child, change in rank, change in occupation, and development of a physical limitation to duty. Using longitudinal data from the Stanford Military Data Repository, which represents all active-duty soldiers aged 17-62 between 2011 and 2014 (n = 827,126), we employed an event history analysis to examine associations between stressful life changes and a subsequent diagnosis of hyperlipidemia, substantial weight gain, and weight-related separation from the Army. Marriage was associated with an increase in the odds of substantial weight gain 3 months later for both men and women. Developing a physical duty limitation was associated with an increase in the odds of a hyperlipidemia diagnosis 2 months later for both men and women, as was substantial weight gain 2 months later. Stressful life changes were also associated with increased odds of nutrition-related health outcomes, although we found gender differences in the magnitude of the associations. Findings could be used to mitigate the effects of stress on health by health professionals.

Sickle cell trait and renal disease among African American U.S. Army soldiers.

Sickle cell trait and certain renal disorders are disproportionately prevalent among African American individuals, so a clear understanding of their association is important. We conducted a longitudinal study using the Stanford Military Data Repository to examine sickle cell trait in relation to the incidence of acute kidney injury (AKI) and chronic kidney disease (CKD). Our study population consisted of African American U.S. Army soldiers on active duty between January 2011 and December 2014. The cumulative incidence was 0·51% for AKI (236 cases out of 45 901 soldiers) and 0·56% for CKD (255 cases out of 45 882 soldiers). Discrete time logistic regression models adjusting for demographic-, military- and healthcare-related covariates showed that sickle cell trait was associated with significantly higher adjusted odds of both AKI [odds ratio (OR): 1·74; 95% confidence interval (CI): 1·17-2·59] and CKD (OR: 2·00; 95% CI: 1·39-2·88). Elevated odds of AKI and CKD were also observed in association with prior CKD and AKI, respectively, and with obesity and prior hypertension. Individuals with sickle cell trait and their providers should be aware of the possibility of increased risk of AKI and CKD to allow for timely intervention and possible prevention.

Association of Nonsteroidal Anti-inflammatory Drug Prescriptions With Kidney Disease Among Active Young and Middle-aged Adults.

Importance: Concern about the renal effects of nonsteroidand al anti-inflammatory drugs (NSAIDs) among young, healthy adults has been limited, but more attention may be warranted given the prevalent use of these agents. Objective: To test for associations between dispensed NSAIDs and incident acute kidney injury and chronic kidney disease while controlling for other risk factors. Design, Setting, and Participants: This retrospective, longitudinal cohort study used deidentified medical and administrative data on 764 228 active-duty US Army soldiers serving between January 1, 2011, and December 31, 2014. Analysis was conducted from August 1 to November 30, 2018. All individuals new to Army service were included in the analysis. Persons already serving in January 2011 were required to have at least 7 months of observable time to eliminate those with kidney disease histories. Exposures: Mean total defined daily doses of prescribed NSAIDs dispensed per month in the prior 6 months. Main Outcomes and Measures: Incident outcomes were defined by diagnoses documented in health records and a military-specific digital system. Results: Among the 764 228 participants (655 392 [85.8%] men; mean [SD] age, 28.6 [7.9] years; median age, 27.0 years [interquartile range, 22.0-33.0 years]), 502 527 (65.8%) were not dispensed prescription NSAIDs in the prior 6 months, 137 108 (17.9%) were dispensed 1 to 7 mean total defined daily doses per month, and 124 594 (16.3%) received more than 7 defined daily doses per month. There were 2356 acute kidney injury outcomes (0.3% of participants) and 1634 chronic kidney disease outcomes (0.2%) observed. Compared with participants who received no medication, the highest exposure level was associated with significantly higher adjusted hazard ratios (aHRs) for acute kidney injury (aHR, 1.2; 95% CI, 1.1-1.4) and chronic kidney disease (aHR, 1.2; 95% CI, 1.0-1.3), with annual outcome excesses per 100 000 exposed individuals totaling 17.6 cases for acute kidney injury and 30.0 cases for chronic kidney disease. Conclusions and Relevance: Modest but statistically significant associations were noted between the highest observed doses of NSAID exposure and incident kidney problems among active young and middle-aged adults.

Trajectories of body mass index among active-duty U.S. Army soldiers, 2011-2014.

Establishing the shape and determinants of trajectories of body mass index (BMI) among Soldiers is critical given the importance of weight management to military service requirements. To establish the shape and determinants of BMI trajectories among Soldiers, we aimed to (1) model the overall BMI trajectory of Soldiers, (2) find the most common trajectory groups among Soldiers, (3) investigate the relationship between BMI trajectories and sociodemographic and military-specific characteristics, and (4) determine if there were Soldiers with large fluctuations in BMI. The study population included all US Army Soldiers on active-duty between 2011 and 2014 who were age 17-62 (n = 827,126). With longitudinal data from the Stanford Military Data Repository, we used group-based trajectory modeling to identify the BMI trajectories of Soldiers and multinomial logistic regression to estimate associations between Soldier characteristics and trajectory membership. Four distinct BMI trajectory groups were found: increasing, decreasing, constant, and inconstant. The constant, increasing, and decreasing trajectories were similar in shape and percentage between men and women. The constant trajectory had the fewest Soldiers who exceeded weight standards or had duty limitations. The increasing trajectory was associated with marriage and fewer service years. The decreasing trajectory was associated with more service years and higher educational attainment. The inconstant trajectory differed in shape between men and women. Over 6% of men and 12% of women had fluctuations in BMI indicative of weight cycling. Understanding the characteristics associated with BMI trends may assist the Army in targeting resources aimed to improve Soldier health and combat readiness.

Gender differences in the associations of body mass index, physical fitness and tobacco use with lower extremity musculoskeletal injuries among new US Army soldiers.

BACKGROUND: Musculoskeletal (MSK) injuries are a leading cause of morbidity among US Army soldiers, especially among women and the newly enlisted. While extremes of body mass index (BMI), low physical fitness and tobacco use have been identified as risk factors, no prior studies have determined the combined effects of these risk factors or tested for gender differences in the associations. METHODS: We conducted a retrospective cohort study utilising the Stanford Military Data Repository to study all enlisted soldier accessions to the US Army between January 2011 and January 2014, with follow-up through December 2014 (n=238 772). We used discrete-time logistic regression to test for associations between demographic, socioeconomic and health behaviour-related predictors and incident lower extremity injuries. We included interaction terms to test for gender differences. RESULTS: Among men, there were greater adjusted odds of injury among underweight (OR 1.27), overweight (OR 1.14) and obese soldiers (OR 1.54) (all p<0.001) relative to normal-weight soldiers. No statistically significant differences in the odds of injury on the basis of BMI were observed for female soldiers. Physical fitness was a significantly stronger predictor of injury for female as compared with male soldiers, while the association between tobacco use and injury was stronger for men (OR 1.47) than for women (OR 1.30) (p<0.001 for both). CONCLUSION: This is the largest known study to simultaneously assess important, modifiable musculoskeletal injury risk factors and to test for gender differences in these associations. These findings provide critical gender-related nuances for clinicians and leaders seeking to reduce the risk of these problems.

Timing and Predictors of Mild and Severe Heat Illness among New Military Enlistees.

PURPOSE: Heat illnesses are important and potentially fatal conditions among physically active individuals. We determined predictors of heat illness among enlistees in a large military population experiencing common physical activity patterns. METHODS: We estimated the adjusted odds of mild (MHI) and severe (SHI) heat illness associated with demographic, health-related, and geographic factors among active-duty, US Army soldiers enlisting between January 2011 and December 2014 (N = 238,168) using discrete-time multivariable logistic regression analyses. RESULTS: We observed 2612 incident cases of MHI and 732 incident cases of SHI during 427,922 person-years of follow-up, with a mean and median of 21.6 and 21 months per subject. During the first 6 duty months, 71.3% of the MHIs and 60.2% of the SHIs occurred, peaking at month 2. The odds of MHI quadrupled among those with prior SHI (odds ratio [OR], 4.02; 95% confidence interval [CI], 2.67-6.03). Body mass index (BMI) extremes increased the odds substantially (OR at BMI ≥30 kg·m: for MHI, 1.41 (CI, 1.19-1.67); for SHI, 1.94 (CI, 1.47-2.56); OR at BMI <18.5 kg·m: for MHI, 1.50 (CI, 1.01-2.21); for SHI, 2.26 (CI, 1.16-4.39)). Tobacco use was associated with a 55% increase (CI, 1.37-1.77) in MHI odds. The odds of MHI increased if taking nonsteroidal anti-inflammatory drugs, opioids, or methylphenidate stimulants. Lower age and lower entry aptitude scores were associated with progressively increased MHI odds. CONCLUSIONS: Most heat illnesses occurred at the outset of service, indicating the need for focused prevention methods at the initiation of military duty. Prior heat illness, BMI extremes, medications, and tobacco use represent potentially actionable risk factors to address by education, policy, and/or clinician intervention.

Deployment and Preterm Birth Among US Army Soldiers.

With increasing integration of women into combat roles in the US military, it is critical to determine whether deployment, which entails unique stressors and exposures, is associated with adverse reproductive outcomes. Few studies have examined whether deployment increases the risk of preterm birth; no studies (to our knowledge) have examined a recent cohort of servicewomen. We therefore used linked medical and administrative data from the Stanford Military Data Repository for all US Army soldiers with deliveries between 2011 and 2014 to estimate the associations of prior deployment, recency of deployment, and posttraumatic stress disorder with spontaneous preterm birth (SPB), adjusting for sociodemographic, military-service, and health-related factors. Of 12,877 deliveries, 6.1% were SPBs. The prevalence was doubled (11.7%) among soldiers who delivered within 6 months of their return from deployment. Multivariable discrete-time logistic regression models indicated that delivering within 6 months of return from deployment was strongly associated with SPB (adjusted odds ratio = 2.1, 95% confidence interval: 1.5, 2.9). Neither multiple past deployments nor posttraumatic stress disorder was significantly associated with SPB. Within this cohort, timing of pregnancy in relation to deployment was identified as a novel risk factor for SPB. Increased focus on servicewomen's pregnancy timing and predeployment access to reproductive counseling and effective contraception is warranted.

Sickle Cell Trait and Heat Injury Among US Army Soldiers.

There is concern that sickle cell trait (SCT) increases risk of exertional collapse, a primary cause of which is heat injury. However, to our knowledge, no population-based studies among active individuals have addressed this, representing a critical evidence gap. We conducted a retrospective cohort study of SCT-tested African-American soldiers who were on active duty in the US Army anytime between January 2011 and December 2014. Using Cox proportional hazards models and adjusting for demographic and medical factors, we observed no significant associations between SCT and either mild heat injury (hazard ratio (HR) = 1.15, 95% confidence interval (CI): 0.84, 1.56; n = 45,999) or heat stroke (HR = 1.11, 95% CI: 0.44, 2.79; n = 46,183). Risk of mild heat injury was substantially higher among soldiers with recent prescriptions for antipsychotic agents (HR = 3.25, 95% CI: 1.33, 7.90). Risk of heat stroke was elevated among those with a prior mild heat injury (HR = 17.7, 95% CI: 8.50, 36.7) and among overweight and obese individuals (HR = 2.91 (95% CI: 1.38, 6.17) and HR = 4.04 (95% CI: 1.72, 9.45), respectively). In a setting where universal precautions are utilized to mitigate risk of exertion-related illnesses, SCT is not associated with either mild heat injury or heat stroke.

Objective Effects of Breast Reduction Surgery on Physical Fitness.

BACKGROUND: Reduction mammaplasty is known for excellent outcomes and patient satisfaction. Although patients report improvements in pain, weight loss, and exercise levels, objective data on physical fitness benefits are limited. METHODS: Using the Stanford Military Data Repository, we identified 89 US Army active duty women with at least 1 pre- and postoperative Army Physical Fitness Test (APFT) who underwent reduction mammaplasty during 2011 to 2014. We used paired t tests to compare pre- and postoperative APFT score means and raw values for push-ups, sit-ups, and the 2-mile run. RESULTS: There were 56 subjects (62.9%) who improved in total APFT scores. Total score means increased from 235.9 preoperatively to 243.4 postoperatively (P = 0.0065). Of 28 subjects with at least 2 APFT scores before and after surgery, 20 (71.4%) improved in total scores. The subgroup's mean total score increased from 237.8 to 251.3 (P = 0.0009). Comparing individual pre- and postprocedure APFTs, all subjects demonstrated a mean 3.9% (SD, 0.1) improvement in total scores, and the subpopulation of 28 improved by 6.3% (SD, 0.1). In all events, mean performance values trended toward better postoperative scores. Differences were statistically significant for the total population for the number of sit-ups (P = 0.035), and, for the subgroup of 28, differences were statistically significant for the total score (P = 0.0009), sit-ups (P = 0.0002), and push-ups (P = 0.0134). CONCLUSIONS: Reduction mammaplasty was associated with postoperative physical fitness improvements among US Army active duty women. Soldier data are useful for objectively assessing physical fitness effects of breast reduction surgery.

Long-Acting Reversible Contraceptive Placement Among Active-Duty U.S. Army Servicewomen.

OBJECTIVE: To quantify uptake of long-acting reversible contraceptives (LARC)-intrauterine devices (IUDs) and hormonal implants-among U.S. Army active-duty female soldiers and identify characteristics associated with uptake. METHODS: This retrospective cohort study used the Stanford Military Data Repository, which includes all digitally recorded health encounters for active-duty U.S. Army soldiers from 2011 to 2014. We analyzed data from women aged 18-44 years to assess rates of LARC initiation using medical billing codes. We then evaluated predictors of LARC initiation using multivariable regression. RESULTS: Among 114,661 servicewomen, 14.5% received a LARC method; among those, 60% received an IUD. Intrauterine device insertions decreased over the study period (38.7-35.9 insertions per 1,000 women per year, ß=0.14, 95% confidence interval [CI] -0.23 to -0.05, P<.05), whereas LARC uptake increased, driven by an increase in implant insertions (20.3-35.4/1,000 women per year, ß=0.41, CI 0.33-0.48, P<.001). Younger age was a positive predictor of LARC uptake: 32.4% of IUD users and 62.6% of implant users were in the youngest age category (18-22 years) compared with 9.6% and 2.0% in the oldest (36-44 years). The likelihood of uptake among the youngest women (compared with oldest) was most marked for implants (adjusted relative risk 7.12, CI 5.92-8.55; P<.001). A total of 26.2% of IUD users had one child compared with 13.2% among non-LARC users (adjusted relative risk 1.94, CI 1.85-2.04, P<.001). The majority (52.2%) of those initiating IUDs were married, which was predictive of uptake over never-married women (adjusted relative risk 1.52, CI 1.44-1.59, P<.001). CONCLUSION: Among servicewomen, we observed low but rising rates of LARC insertion, driven by increasing implant use. Unmarried and childless soldiers were less likely to initiate LARC. These findings are consistent with potential underutilization and a need for education about LARC safety and reversibility in a population facing unique consequences for unintended pregnancies.