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.

Knowledge and Attitudes Regarding Human Papillomavirus Among Active Duty Service Members at a Large Military Base.

OBJECTIVE: To assess gaps in human papillomavirus (HPV) knowledge and current attitudes toward HPV vaccination among active duty soldiers at Fort Bragg, NC, and to evaluate the impact of the instruction intervention on knowledge and attitudes regarding HPV vaccination. METHODS: A six-question assessment was administered to soldiers presenting for appointments through the Epidemiology and Disease Control (EDC) Clinic at Fort Bragg in January 2020. Questions included five multiple choice knowledge assessments and a Likert scale attitude question regarding HPV vaccination. The assessment was administered before and after a one-on-one educational intervention conducted by the EDC Clinic nursing staff. Pre- and post-assessments were matched using unique encounter numbers. RESULTS: A total of 139 matched pre- and post-education assessments were completed. Statistically significant changes in HPV knowledge were observed in test score and percent correct (P < .001). Additionally, for individuals reporting no prior HPV vaccination, attitudes toward receiving it increased from 4 (interquartile range 3-5) to 5 (4-5) following instructions (P < .001). This indicates a shift from moderately interested to very interested. CONCLUSIONS: Results among soldiers demonstrated a lack of knowledge regarding HPV infection, its long-term effects, and preventive measures available among this population of active duty members. Assessment results also illustrated education about HPV infection and vaccination positively impacts soldiers' knowledge and attitudes toward HPV vaccination.

Prospective screening for sexually transmitted infections among US service members with Chlamydia trachomatis or Neisseria gonorrhoeae infection.

BACKGROUND: Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are the most common bacterial causes of sexually transmitted infection (STI) in the United States (US). The purpose of this study was to determine the frequency of reinfection during a six-month study period and to evaluate the retesting interval for those infected with CT or NG. METHODS: We conducted a prospective, six-month follow-up study among US military personnel with new onset, laboratory-confirmed CT or NG, recruited from an STI clinic at a large military base from January 2018 to January 2020. Each participant was randomly assigned to one of four groups, which differed only by the timing of the first study-associated follow-up visit after CT or NG diagnosis. RESULTS: Of the 347 initially recruited into the study, 267 participants completed a follow-up visit prior to their scheduled, final visit 6 months after initial infection. The median age at enrollment was 22 years and 41.0% were female. There were 32 (12.0%) reinfections (30 CT and 2 NG) after treatment of an index diagnosis of CT or NG within the six-month study period. Six of the CT reinfections were only detected at the final visit. A review of medical records revealed additional CT and NG reinfections. The probability of detecting a reinfection did not vary significantly by timing of follow-up. CONCLUSIONS: The likelihood of detecting CT or NG reinfection did not differ according to time of follow up visit among study participants, thus supporting CDC guidance to retest three months post treatment. Efforts should continue to focus on STI prevention and risk reduction.

EatWellNow: Formative Development of a Place-Based Behavioral "Nudge" Technology Intervention to Promote Healthier Food Purchases among Army Soldiers.

Approximately 17% of military service members are obese. Research involving army soldiers suggests a lack of awareness of healthy foods on post. Innovative approaches are needed to change interactions with the military food environment. Two complementary technological methods to raise awareness are geofencing (deliver banner ads with website links) and Bluetooth beacons (real-time geotargeted messages to mobile phones that enter a designated space). There is little published literature regarding the feasibility of this approach to promote healthy behaviors in retail food environments. Thus, we conducted a formative feasibility study of a military post to understand the development, interest in, and implementation of EatWellNow, a multi-layered interactive food environment approach using contextual messaging to improve food purchasing decisions within the military food environment. We measured success based on outcomes of a formative evaluation, including process, resources, management, and scientific assessment. We also report data on interest in the approach from a Fort Bragg community health assessment survey (n = 3281). Most respondents agreed that they were interested in receiving push notifications on their phone about healthy options on post (64.5%) and that receiving these messages would help them eat healthier (68.3%). EatWellNow was successfully developed through cross-sector collaboration and was well received in this military environment, suggesting feasibility in this setting. Future work should examine the impact of EatWellNow on military service food purchases and dietary behaviors.

Pre-existing Thyroid Autoimmunity and Risk of Papillary Thyroid Cancer: A Nested Case-Control Study of US Active-Duty Personnel.

PURPOSE: Thyroid autoimmunity has been associated with differentiated thyroid cancer although multiple potential biases might have influenced the results of previous studies. METHODS: We conducted a case-control study nested within the cohort of US active-duty personnel 1996-2014 to assess the association between thyroid autoimmunity, defined by serology, and thyroid cancer diagnosis. The primary exposure was thyroid peroxidase (TPO) antibody status 7-10 years before the thyroid cancer index date. We also assessed whether diagnosis of thyroid autoimmunity mediated any associations identified and if thyroid cancer features differed by autoimmunity status. RESULTS: Among 451 incident cases of papillary thyroid cancer and matched controls (median age 36 years, 61.4% men), TPO antibody positivity (v negative) 7-10 years prediagnosis was associated with thyroid cancer (odds ratio [OR] 1.90 [95% CI, 1.33 to 2.70]). Exploratory analyses suggested an increasing risk of thyroid cancer with higher TPO antibody titer (TPO antibody 550-1,399 IU/mL: OR 2.95 [95% CI, 1.37 to 6.36]; and ≥ 1,400 IU/mL: OR 3.91 [95% CI, 1.66 to 9.24]). Positive TPO antibody status remained associated with thyroid cancer after those with diagnosed autoimmunity were excluded, and the association was not mediated by diagnosis of thyroid autoimmunity. Among the cases with diagnosed autoimmunity, 58% thyroid cancers were ≤ 10 mm diameter. CONCLUSION: Longstanding prior thyroid autoimmunity up to 10 years before thyroid cancer diagnosis was associated with papillary thyroid cancer risk. The results could not be fully explained by diagnosis of thyroid autoimmunity although when autoimmunity had been identified, thyroid cancers were diagnosed at a very early stage.

Self-reported physical activity and preaccession fitness testing in U.S. Army applicants.

The Assessment of Recruit Motivation and Strength (ARMS) study evaluated a physical fitness screening test for Army applicants before basic training. This report examines applicants' self-reported physical activity as a predictor of objective fitness measured by ARMS. In 2006, the ARMS study administered a fitness test and physical activity survey to Army applicants during their medical evaluation, using multiple logistic regression for comparison. Among both men and women, "qualified" and "exceeds-body-fat" subjects who met American College of Sports Medicine adult physical activity guidelines were more likely to pass the fitness test. Overall, subjects who met physical activity recommendations, watched less television, and played on sports teams had a higher odds of passing the ARMS test after adjustment for age, race, and smoking status. This study demonstrates that self-reported physical activity was associated with physical fitness and may be used to identify those at risk of failing a preaccession fitness test.

U.S. military recruits waived for pathological curvature of the spine: increased risk of discharge from service.

Selective accession waivers for medically disqualifying conditions like spinal curvature are one way the military meets its manpower needs. We evaluated retention patterns during the first 2 years of service of a cohort of military recruits with waivers for pathological curvature of the spine (spinal curvature). Recruits waived for spinal curvature (n = 417), who accessed from 1998 to 2005 were identified and matched with 3 qualified recruits. Kaplan-Meier survival analysis and Cox proportional hazards model were used to compare survival patterns and adjusted attrition hazard estimates. Waived recruits experienced significantly increased risk of "all cause" discharge (relative risk = 1.3; 95% confidence interval: 1.1, 1.5) and "existing prior to service" discharge (relative risk = 2.4; confidence interval: 1.6, 3.5). Despite the increased risk of discharge, current waiver criteria allowed a majority with spinal curvature to complete at least 2 years of service. Policy makers must consider risks and benefits before modifying the current accession standard for spinal curvature.

Increased prevalence of the pfdhfr/phdhps quintuple mutant and rapid emergence of pfdhps resistance mutations at codons 581 and 613 in Kisumu, Kenya.

BACKGROUND: Anti-malarial drug resistance in Kenya prompted two drug policy changes within a decade: sulphadoxine-pyrimethamine (SP) replaced chloroquine (CQ) as the first-line anti-malarial in 1998 and artemether-lumefantrine (AL) replaced SP in 2004. Two cross-sectional studies were conducted to monitor changes in the prevalence of molecular markers of drug resistance over the period in which SP was used as the first-line anti-malarial. The baseline study was carried out from 1999-2000, shortly after implementation of SP, and the follow-up study occurred from 2003-2005, during the transition to AL. MATERIALS AND METHODS: Blood was collected from malaria smear-positive, symptomatic patients presenting to outpatient centers in Kisumu, Kenya, during the baseline and follow-up studies. Isolates were genotyped at codons associated with SP and CQ resistance. In vitro IC50 values for antifolates and quinolones were determined for isolates from the follow-up study. RESULTS: The prevalence of isolates containing the pfdhfr N51I/C59R/S108N/pfdhps A437G/K540E quintuple mutant associated with SP-resistance rose from 21% in the baseline study to 53% in the follow-up study (p < 0.001). Isolates containing the pfdhfr I164L mutation were absent from both studies. The pfdhps mutations A581G and A613S/T were absent from the baseline study but were present in 85% and 61%, respectively, of isolates from the follow-up study. At follow-up, parasites with mutations at five pfdhps codons, 436, 437, 540, 581, and 613, accounted for 39% of isolates. The CQ resistance-associated mutations pfcrt K76T and pfmdr1 N86Y rose from 82% to 97% (p = 0.001) and 44% to 76% (p < 0.001), respectively, from baseline to follow-up. CONCLUSIONS: During the period in which SP was the first-line anti-malarial in Kenya, highly SP-resistant parasites emerged, including isolates harboring pfdhps mutations not previously observed there. SP continues to be widely used in Kenya; however, given the highly resistant genotypes observed in this study, its use as a first-line anti-malarial should be discouraged, particularly for populations without acquired immunity to malaria. The increase in the pfcrt K76T prevalence, despite efforts to reduce CQ use, suggests that either these efforts are not adequate to alleviate CQ pressure in Kisumu, or that drug pressure is derived from another source, such as the second-line anti-malarial amodiaquine.

Exertional heat illness among overweight U.S. Army recruits in basic training.

INTRODUCTION: Heat illness has not declined in the U.S. military despite preventive measures. The increase in overweight recruits entering the U.S. military may lead to an increase in heat-related events. This study compares the risk of heat illness among U.S. Army recruits who exceeded body fat standards at accession to those who met standards. METHODS: Recruits with excess body fat and qualified applicants to the Army were required to take a preaccession fitness test during the study period (February 2005 through September 2006). The test included a 5-min step test and 1-min push-up challenge, scored as pass or fail. Incidence and outpatient usage for heat illness (any heat illness, heat stroke, heat exhaustion, and other heat illness) at 90 d of service were compared in 9667 male recruits of whom 826 had excess body fat and 8841 were qualified. There were too few heat events among women for analysis. RESULTS: The incidence odds ratio among male recruits with excess body fat compared to qualified male recruits was 3.63 (95% CI: 1.92, 6.85). Men with excess body fat had an increased incidence of heat illness with a rate ratio of 7.25 (95% CI: 4.17, 12.61). DISCUSSION: Although there were few heat illness events, the results indicate a significantly increased risk of heat illness and outpatient utilization among male recruits with excess body fat. It was estimated that approximately 70% of the relative risk for heat illnesses in men with excess body fat during basic training was associated with exceeding body fat standards. These findings may have implications for military accession and training.

Descriptive epidemiology of bipolar I disorder among United States military personnel.

Psychiatric disorders in military members require substantial medical, administrative, and financial resources, and are among the leading causes of hospitalization and early discharge. We reviewed available data to better understand the incidence of bipolar I disorder among military personnel. Defense Medical Epidemiology Database inpatient data were used. Descriptive and comparative statistics were performed. From 1997-2006 there were 3,317 first hospitalizations for bipolar I disorder with a mean of 1.2 hospitalizations per case. The rate of first occurrence among this adult population was 0.24 per 1,000 person-years. The incidence increased over time for depressed and mixed episode types among both genders. High risk groups include women, younger individuals, and whites. This population provides insight into adult onset bipolar I disorder incidence and demographic patterns not available elsewhere and offers potential opportunities to improve its understanding.

Association of weight at enlistment with enrollment in the Army Weight Control Program and subsequent attrition in the Assessment of Recruit Motivation and Strength Study.

The ongoing obesity epidemic has made recruiting qualified Army applicants increasingly difficult. A cohort of 10,213 Army enlisted subjects was enrolled in the Assessment of Recruit Motivation and Strength (ARMS) study from February 2005 through September 2006. Overweight recruits obtained a waiver for enlistment (n = 990) if they passed a screening physical fitness test. Recruits were evaluated for enrollment into the Army Weight Control Program (AWCP) and discharged during the 15 months following enlistment. Enrollment was higher among overweight recruits than recruits who met entrance standards (men: adjusted OR = 13.3 [95% CI: 10.3, 17.2]; women: adjusted OR = 3.6 [3.3, 3.9]). Although the discharge frequency was higher in the waiver group than in those who met standards (25.4% versus 19.9%, p < 0.001), there were only 10 (0.5% of total) discharges directly attributed to weight. Granting overweight waivers through the ARMS program increases enrollment to the AWCP but has little effect on weight-related attrition.

Preaccession fitness and body composition as predictors of attrition in U.S. Army recruits.

The Assessment of Recruit Motivation and Strength (ARMS) project evaluated whether active duty Army enlistees who exceeded weight and body-fat standards but were able to pass the ARMS physical fitness test were at elevated risk of early attrition relative to the traditional recruit population. Attrition among 1146 overweight and overbody-fat (OBF) recruits who passed ARMS was compared to 10,514 fully qualified (FQ) recruits who began service in February 2005 through September 2006. The ARMS test includes a 5-minute step test and a 1-minute pushup test. There were no significant differences in attrition between OBF and FQ at 180 days: adjusted hazard ratios were 1.17 (95% CI: 0.83, 1.65) among females and 1.23 (95% CI: 0.95, 1.58) among males. This study indicates that physically fit recruits who exceeded weight/body-fat standards were equally capable of serving at least 180 days compared to those who met standards.

A Systems Evaluation of Occupational Injuries and Illness in the US Army.

OBJECTIVE: Workers' compensation (WC) processes do not lead to maximal return-to-work or cost savings. The aim of this study is to assess barriers and facilitators to reporting and managing injuries and illnesses among civilian employees in the US Army. METHODS: We triangulated a review of policy and practice documents, stakeholder interviews, a descriptive analysis of WC data, and a literature review to inform recommendations of best practices for improving return-to-work and lowering WC costs. RESULTS: Federal WC costs are trending downward for civilian employees in the US Army; however, the approaches are not uniform or optimized, especially at the installation level. CONCLUSIONS: This mixed methods evaluation of the Department of Defense WC elucidates areas for improvement and potential best practices within the Federal WC system.

Differentiating between smokers and nonsmokers using serum cotinine.

Aim: Our goal is to evaluate implications of cotinine cut points in subgroups of smokers and nonsmokers. Materials & methods: Data were assessed from 13,357 adult participants and collected over a period of 6 years by the National Health and Nutrition Examination Survey (2009-2014). Receiver operating characteristic curve analysis was used to identify optimal cut points. Rao-Scott χ2 tests measured associations between group characteristics. Results: The optimal serum cotinine cut point adult cigarette smokers was 3.63 ng/ml (sensitivity of 96.7%; specificity of 93.0%). This cut point differed by gender as well as race/ethnicity. Conclusion: There are notable differences in subgroup cut points compared with previous research. Use of gender or race/ethnicity specific cut points is more appropriate when feasible and may help clinician recommendations.

Seroprevalence of Chikungunya virus (CHIKV) infection on Lamu Island, Kenya, October 2004.

An outbreak of Chikungunya virus (CHIKV) disease associated with high fever and severe protracted arthralgias was detected in Lamu, Kenya, peaking in July 2004. At least 1,300 cases were documented. We conducted a seroprevalence study to define the magnitude of transmission on Lamu Island. We conducted a systematic cross-sectional survey. We administered questionnaires and tested 288 sera from Lamu residents for IgM and IgG antibodies to CHIKV. Chikungunya virus infection (seropositivity) was defined as a person with IgG and/or IgM antibodies to CHIKV. IgM antibodies to CHIKV were detected in 18% (53/288) and IgG antibodies in 72% (206/288); IgM and/or IgG antibodies were present in 75% (215/288). The seroprevalence findings suggested that the outbreak was widespread, affecting 75% of the Lamu population; extrapolating the findings to the entire population, 13,500 (95% CI, 12,458-14328) were affected. Vector control strategies are needed to control the spread of this mosquito-borne infection.

Rapid spread of Vibrio cholerae O1 throughout Kenya, 2005.

Between January and June 2005, 5 distinct cholera outbreaks occurred in Kenya. Overall, 990 cases and 25 deaths (2.5%) were reported. Four outbreaks occurred in towns along major highways, and 1 occurred in a refugee camp near the Sudanese border, accessible to Nairobi by daily flights. Matched case-control studies from 2 outbreaks showed that failure to treat drinking water and storing drinking water in wide-mouthed containers were significantly associated with disease. Isolates from all 5 outbreaks were Vibrio cholerae O1, Inaba serotype, and had genetically similar PFGE patterns of SfiI-digested chromosomal DNA. Linkage of the outbreak locations by major transportation routes, their temporal proximity, and similar PFGE patterns of isolates suggests the outbreaks might have been linked epidemiologically, showing the speed and distance of cholera spread in countries like Kenya with pockets of susceptible populations connected by modern transportation. Prevention measures remain implementation of point-of-use safe water systems and case finding and referral.

Epidemiological Evidence and Possible Mechanisms for the Association Between Cigarette Smoking and Injuries (Part 1).

Surveys indicated that 24% of military personnel are current cigarette smokers. Smoking is well known to increase the risk of cancers, cardiovascular and respiratory diseases, reproductive problems, and other medical maladies, but one of the little known effects of smoking is that on injuries. There is considerable evidence from a variety of sources that (1) smoking increases overall injury risk, (2) the greater the amount of smoking, the higher is the injury risk, and (3) smoking is an independent injury risk factor. Smoking not only affects the overall injury risk but also impairs healing processes following fractures (e.g., longer healing times, more nonunions, more complications), ligament injury (e.g., lower subjective function scores, greater joint laxity, lower subsequent physical activity, more infections), and wounding (e.g., delayed healing, more complications, less satisfying cosmetic results). Smoking may elicit effects on fractures through low bone mineral density (BMD), lower dietary intake of calcium and vitamin D, altered calcium metabolism, and effects on osteogenesis and sex hormones. Effects on wound healing may be mediated through altered neutrophils and monocytes functions resulting in reduced ability to fight infections and remove damaged tissue, reduced gene expression of cytokines important for tissue healing, and altered fibroblast function leading to lower density and amount of new tissue formation. Limited data suggest smoking cessation has favorable effects on various aspects of bone health over periods of 1 to 30 years. Favorable effects on neutrophil and monocyte functions may occur as early as 4 weeks, but fibroblast function and collagen metabolism (important for wound remodeling) appear to take considerably longer and may be dependent on the amount of prior smoking. Part 2 of this series will use this information to explore the possibility of a causal relationship between smoking and injuries.

Epidemiologic Evidence and Possible Mechanisms for the Association Between Cigarette Smoking and Injuries. Part 2: Is the Relationship Between Smoking and Injuries Causal?

Part 1 of this series reviewed the epidemiologic evidence for the association between cigarette smoking and injuries and possible biological and psychosocial mechanisms to account for this relationship. In the present article, nine criteria are explored to determine if smoking is a direct cause of injuries (i.e., a causal relationship). There is substantial evidence that individuals who smoked in the past have a higher subsequent risk of injury. A recent meta-analysis found that smokers in the military were 1.31 times more likely to be injured than nonsmokers and Servicemembers with low, medium, and high levels of smoking had 1.27, 1.37, and 1.71 times, respectively, the risk of injury compared with nonsmokers. The association between smoking and injuries has been reported in at least 18 US military studies and in 14 civilian studies in seven countries. The biological plausibility of the association was discussed extensively in part 1 of this series. A possible alternative explanation with sufficient data was that smokers may be risk takers and it is the risk-taking behavior that increases injury risk (not smoking per se). Once an individual no longer smokes, a decrease in injury risk has been reported for at least bone health and wound healing. The effects of smoking do not appear to be specific to one type of injury, possibly because of the numerous compounds in tobacco smoke that could affect tissues and physiological processes, with evidence provided for bones, tendons, and healing processes. The association was consistent with other knowledge, with some evidence provided from other types of medical problems and trends in smoking and injury-related mortality. In summary, the association between smoking and injuries appears to meet many of the criteria for a causal relationship.

Drought-associated chikungunya emergence along coastal East Africa.

Epidemics of chikungunya fever, an Aedes spp.-borne viral disease, affected hundreds of thousands of people in western Indian Ocean islands and India during 2005-2006. The initial outbreaks occurred in coastal Kenya (Lamu, then Mombasa) in 2004. We investigated eco-climatic conditions associated with chikungunya fever emergence along coastal Kenya using epidemiologic investigations and satellite data. Unusually dry, warm conditions preceded the outbreaks, including the driest since 1998 for some of the coastal regions. Infrequent replenishment of domestic water stores and elevated temperatures may have facilitated Chikungunya virus transmission. These results suggest that drought-affected populations may be at heightened risk for chikungunya fever, and underscore the need for safe water storage during drought relief operations.

Meta-analysis of Cigarette Smoking and Musculoskeletal Injuries in Military Training.

PURPOSE: Tobacco use is common among military personnel, as is musculoskeletal injury during training. In a review of the literature on musculoskeletal injuries, there was mixed evidence on the role of smoking as a risk factor. The purpose of this study is to review and analyze the literature on the impact of cigarette smoking on lower-extremity overuse injuries in military training. METHODS: We performed a literature search on articles published through October 2016. Search terms focused on lower-extremity overuse musculoskeletal injuries and cigarette smoking in military populations. We conducted a meta-analysis overall and by sex, including smoking intensity. RESULTS: We identified 129 potential studies and selected 18 based on quality. The overall rate ratio for smoking was 1.31, 1.31 for men, and 1.23 for women. Overall and for each sex, rate ratios were significantly greater than 1.0 for each intensity level of smoking. CONCLUSIONS: Smoking is a moderate risk factor for musculoskeletal injury and may account for a meaningful proportion of injuries among men and women due to the high prevalence of smoking and injury in this population. Although enlistees are not allowed to smoke during basic training, their risk of injury remains high, indicating that smokers may remain at increased risk for medium- to long-term duration.