Military Cohort Study Research Articles

Post-traumatic growth among UK military personnel deployed to Iraq or Afghanistan: data from phase 3 of a military cohort study.

Post-traumatic growth (PTG) refers to beneficial psychological change following trauma. This study explores the sociodemographic, health and deployment-related factors associated with PTG in serving/ex-serving UK armed forces personnel deployed to military operations in Iraq or Afghanistan. Multinomial logistic regression analyses were applied to retrospective questionnaire data collected 2014-2016, stratified by gender. PTG scores were split into tertiles of no/very low PTG, low PTG and moderate/large PTG. A total of 1447/4610 male personnel (30.8%) and 198/570 female personnel (34.8%) reported moderate/large PTG. Male personnel were more likely to report moderate/large PTG compared with no/very low PTG if they reported a greater belief of being in serious danger (relative risk ratio (RRR) 2.47, 95% CI 1.68-3.64), were a reservist (RRR 2.37, 95% CI 1.80-3.11), reported good/excellent general health (fair/poor general health: RRR 0.33, 95% CI 0.24-0.46), a greater number of combat experiences, less alcohol use, better mental health, were of lower rank or were younger. Female personnel were more likely to report moderate/large PTG if they were single (in a relationship: RRR 0.40, 95% CI 0.22-0.74), had left military service (RRR 2.34, 95% CI 1.31-4.17), reported better mental health (common mental disorder: RRR 0.37, 95% CI 0.17-0.84), were a reservist, reported a greater number of combat experiences or were younger. Post-traumatic stress disorder had a curvilinear relationship with PTG. A moderate/large degree of PTG among the UK armed forces is associated with mostly positive health experiences, except for post-traumatic stress disorder.

Self-reported auditory problems are associated with adverse mental health outcomes and alcohol misuse in the UK Armed Forces

PurposeAuditory problems, such as hearing loss and tinnitus, have been associated with mental health problems and alcohol misuse in the UK general population and in the US Armed Forces; however, few studies have examined these associations within the UK Armed Forces. The present study examined the association between auditory problems and probable common mental disorders, post-traumatic stress disorder and alcohol misuse.Methods5474 serving and ex-service personnel from the UK Armed Forces were examined, selected from those who responded to phase two (data collection 2007–09) and phase three (2014–16) of a military cohort study. Multivariable logistic regression was used to examine the association between auditory problems at phase two and mental health problems at phase three.Results9.7% of participants reported ever experiencing hearing problems alone, 7.9% reported tinnitus within the last month alone, and 7.8% reported hearing problems with tinnitus. After adjustment, hearing problems with tinnitus at phase two was associated with increased odds of probable common mental disorders (AOR = 1.50, 95% CI 1.09–2.08), post-traumatic stress disorder (AOR = 2.30, 95% CI 1.41–3.76), and alcohol misuse (AOR = 1.94, 95% CI 1.28–2.96) at phase three. Tinnitus alone was associated with probable post-traumatic stress disorder (AOR = 1.80, 95% CI 1.03–3.15); however, hearing problems alone were not associated with any outcomes of interest.ConclusionsThe association between auditory problems and mental health problems emphasises the importance of the prevention of auditory problems in the Armed Forces: through enhanced audiometric screening, improved hearing protection equipment, and greater levels of utilisation of such equipment.

Hospital admissions for non-communicable disease in the UK military and associations with alcohol use and mental health: a data linkage study

BackgroundSince the recent conflicts in Iraq and Afghanistan, the short-term focus of military healthcare research has been on the consequences of deployment for mental health and on those wounded or injured in combat. Now that these conflicts have ended for the UK Armed Forces, it is important to consider the longer term physical and mental health consequences, and just as importantly, the links between these. The aims of this study were to determine the most common physical conditions requiring a hospital admission in UK military personnel and whether they were more common in personnel with a mental health condition, smokers, and/or those misusing alcohol compared to those without.MethodsData linkage of a prospective UK military cohort study to electronic admitted patient care records for England, Wales and Scotland. Nine thousand nine hundred ninety military personnel completed phase 2 of a military cohort study (56% response rate, data collected from 2007 to 2009), with analyses restricted to 86% of whom provided consent for linkage to healthcare records (n = 8602). Ninety percent were male and the mean age at phase 2 was 36 years. The outcome was physical non communicable diseases (NCDs) requiring a hospital admission which occurred after phase 2 of the cohort when the mental health, smoking and alcohol use exposure variables had been assessed until the end of March 2014.ResultsThe most common NCDs requiring a hospital admission were gastrointestinal disorders 5.62% (95% Confidence Intervals (CI) 5.04, 6.19) and joint disorders 5.60% (95% CI 5.02, 6.18). Number of NCDs requiring a hospital admission was significantly higher in those with a common mental disorder (Hazard ratio (HR) 1.40 (95% CI 1.16–1.68), post-traumatic stress disorder (HR 1.78 (95% CI 1.32–2.40)) and in current smokers (HR 1.35 (95% CI 1.12–1.64) compared to those without the disorder, and non-smokers, respectively.ConclusionsMilitary personnel with a mental health problem are more likely to have an inpatient hospital admission for NCDs compared to those without, evidencing the clear links between physical and mental health in this population.

Mental health outcomes at the end of the British involvement in the Iraq and Afghanistan conflicts: a cohort study.

Little is known about the prevalence of mental health outcomes in UK personnel at the end of the British involvement in the Iraq and Afghanistan conflicts.AimsWe examined the prevalence of mental disorders and alcohol misuse, whether this differed between serving and ex-serving regular personnel and by deployment status. This is the third phase of a military cohort study (2014-2016; n = 8093). The sample was based on participants from previous phases (2004-2006 and 2007-2009) and a new randomly selected sample of those who had joined the UK armed forces since 2009. The prevalence was 6.2% for probable post-traumatic stress disorder, 21.9% for common mental disorders and 10.0% for alcohol misuse. Deployment to Iraq or Afghanistan and a combat role during deployment were associated with significantly worse mental health outcomes and alcohol misuse in ex-serving regular personnel but not in currently serving regular personnel. The findings highlight an increasing prevalence of post-traumatic stress disorder and a lowering prevalence of alcohol misuse compared with our previous findings and stresses the importance of continued surveillance during service and beyond. All authors are based at King's College London which, for the purpose of this study and other military-related studies, receives funding from the UK Ministry of Defence (MoD). S.A.M.S., M.J., L.H., D.P., S.M. and R.J.R. salaries were totally or partially paid by the UK MoD. The UK MoD provides support to the Academic Department of Military Mental Health, and the salaries of N.J., N.G. and N.T.F. are covered totally or partly by this contribution. D.Mu. is employed by Combat Stress, a national UK charity that provides clinical mental health services to veterans. D.MacM. is the lead consultant for an NHS Veteran Mental Health Service. N.G. is the Royal College of Psychiatrists' Lead for Military and Veterans' Health, a trustee of Walking with the Wounded, and an independent director at the Forces in Mind Trust; however, he was not directed by these organisations in any way in relation to his contribution to this paper. N.J. is a full-time member of the armed forces seconded to King's College London. N.T.F. reports grants from the US Department of Defense and the UK MoD, is a trustee (unpaid) of The Warrior Programme and an independent advisor to the Independent Group Advising on the Release of Data (IGARD). S.W. is a trustee (unpaid) of Combat Stress and Honorary Civilian Consultant Advisor in Psychiatry for the British Army (unpaid). S.W. is affiliated to the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Emergency Preparedness and Response at King's College London in partnership with Public Health England, in collaboration with the University of East Anglia and Newcastle University. The views expressed are those of the author(s) and not necessarily those of the National Health Service, the NIHR, the Department of Health, Public Health England or the UK MoD.

Mortality from multiple sclerosis in British military personnel.

While analysing trends in occupational mortality in England and Wales, we noticed an unexpectedly elevated proportion of deaths from multiple sclerosis (MS) among men in the armed forces. To document and explore possible explanations for the observed excess. We analysed data on underlying cause of death and last full-time occupation for 3,688,916 deaths among men aged 20-74 years in England and Wales during 1979-2010, calculating proportional mortality ratios (PMRs) standardised for age. We compared PMRs for MS in the armed forces with those for each main social class, and in selected other occupations. We also compared PMRs for MS with those for motor neurone disease (MND). The overall PMR for MS in the armed forces during 1979-2010 was 243 (95%CI 203-288). The excess was apparent in each of three separate decades of study (PMRs, ranging from 220 to 259), and across the entire age range. PMRs for MS were not elevated to the same extent in comparator occupations, nor in any of the main social classes. There was no parallel increase in PMRs for MND. These findings suggest that the high proportional mortality from MS in British military personnel is unlikely to have occurred by chance, or as an artefact of the method of investigation. However, the only military cohort study with published results on MS does not support an increased risk. It would be useful to analyse data on MS from other established military cohorts, to check for evidence of a hazard.

Understanding NHS hospital admissions in England, Scotland and Wales: data linkage to the King’s College Military Cohort Study

ABSTRACT
 ObjectiveSecondary health systems in the United Kingdom (UK) are unique for recording Outpatient, Inpatient and Accident & Emergency (A&E) visits in the form of electronic health (eHealth) records. Linking regional healthcare datasets is a problematic, further challenging when linking externally, such as to the King’s College Military Cohort Study (KCMCS). We introduce our methodology used for eRecord linkage.
 ApproacheHealth records from England, Scotland and Wales offer a variety of parameters such as admission/discharge date, diagnosis, treatment/procedure undertaken and the cost of treatment. To acquire eHealth records, unique patient identifiers: NHS number, forename, surname, sex and date of birth extracted from KCMCS were provided to each region. The KCMCS contains self-reported questionnaire results for 9,990 serving/ex-serving military personal, 8,602 participants consented to linkage. eHealth records prepared for linkage in two stages. First, admission and discharge date were checked to ensure a valid date. Second, episodes were checked for consistency, ensuring that no records for individual participants were duplicated. Data available varied based on the region, this disparity between regions can result in data type variation. Hence, linkage was performed on mutual variables to ensure a uniform admission history. Creation of the linked dataset was as follows. First, records and episodes relating to an individual were brought together, to create a personal admission history. Secondly, personal admission history were linked to the KCMCS.
 ResultsLinking to regional health datasets is not without its challenges. England, Scotland and Wales obtain, store and process eHealth records using different methodologies. A total of 6,336 (76.66%) participants were matched by regional health providers, with a total of 61,558 eHealth records. A total of 187 eHealth records were identified and discounted from linkage due to failure to meet criteria listed above. Verifying diagnoses completeness, Inpatient admissions were consistently code, with full completeness. Conversely, Outpatient admissions were poorly coded with 98% lacking any type of diagnosis. In addition, A&E records were sparsely coded; we identified four different regional and local coding systems to identify reason for admission. The eHealth records show promise for identifying health traits of the military. However, further work is required to identify synergy and overcome regional variations.
 ConclusionLinkage techniques provide new opportunities for exploring the health of serving and veteran population. However, quality of identifier and linkage error are still of major concern. Further, record completeness, diagnoses accuracy and data cleaning impact the data quality.

Marital Status Distribution of the U.K. Military: Does It Differ From the General Population?

ABSTRACTThe U.K. media suggest that U.K. military personnel have high divorce rates; to date, these claims are not substantiated. Marital status distribution of the general population and military were compared using data from the Office for National Statistics' marital projections and a military cohort study. Overall, military personnel were more likely to be married and less likely to be divorced than were the general population. Women in the military and married military personnel younger than 30 years of age are more likely to report divorce. Military welfare services might target these groups with programs assisting marital relationships.

Risky driving among UK regular armed forces personnel: changes over time

ObjectivesTo compare the prevalence of self-reported risky driving in a sample of UK military personnel at 2 different time points (2004 and 2009), and to identify the incidence of new...

Adenovirus 36 antibodies associated with clinical diagnosis of overweight/obesity but not BMI gain: a military cohort study.

Obesity is a public health priority, which also threatens national security. Adenovirus 36 (Adv36) increases adiposity in animals and Adv36 antibody status is associated with human obesity, but it is unknown whether infection predicts the development of human adiposity. The objective of the study was to assess infection status and subsequent weight gain. The study had a retrospective cohort design. The study was conducted at Air Force fitness testing and clinical encounters. PARTICIPANTS included Air Force male enlistees, aged 18-22 years, with a baseline body mass index (BMI) of 20-30 kg/m(2) followed up from enlistment (beginning in 1995) until 2012 or separation from the Air Force. EXPOSURE included Adv36 infection status at the time of entry. Follow-up BMI, the primary outcome, and diagnosis of overweight/obesity by the International Classification of Diseases, ninth revision V85.25+ and 278.0* series (secondary outcome) were recorded. The last recorded follow-up BMI was similar among infected and uninfected, 26.4 and 27.2 kg/m(2), respectively (P > .05). However, infected individuals had a higher hazard of a medical provider's diagnosis of overweight/obese over time (hazard ratio 1.8, 95% confidence interval 1.0-3.1, P = .04), adjusted for baseline BMI. Additionally, infected individuals who were lean at baseline (BMI of 22.5 kg/m(2)) had a 3.9 times greater hazard of developing an overweight/obese clinical diagnosis (95% confidence interval 1.5-9.7, P = .004) compared with uninfected lean individuals after adjusting for interaction (P = .03) between infection and baseline BMI. The presence of Adv36 antibodies was not associated with higher BMI at baseline or follow-up within this military population. However, being infected was associated with developing a clinical diagnosis of overweight/obesity, especially among those lean at baseline.

The impact of deployment experience and prior healthcare utilization on enrollment in a large military cohort study.

BackgroundLongitudinal cohort studies are highly valued in epidemiologic research for their ability to establish exposure-disease associations through known temporal sequences. A major challenge in cohort studies is recruiting individuals representative of the targeted sample population to ensure the generalizability of the study’s findings.MethodsWe evaluated nearly 350,000 invited subjects (from 2004-2008) of the Millennium Cohort Study, a prospective cohort study of the health of US military personnel, for factors prior to invitation associated with study enrollment. Multivariable logistic regression was utilized, adjusting for demographic and other confounders, to determine the associations between both deployment experience and prior healthcare utilization with enrollment into the study.ResultsStudy enrollment was significantly greater among those who deployed prior to and/or during the enrollment cycles or had at least one outpatient visit in the 12 months prior to invitation. Mental disorders and hospitalization for more than two days within the past year were associated with reduced odds of enrollment.ConclusionsThese findings suggest differential enrollment by deployment experience and health status, and may help guide recruitment efforts in future studies.

Impact on Mental Health of Deploying as an Individual Augmentee in the U.K. Armed Forces

Armed Forces personnel who deploy as individual augmentees (IAs), with a unit other than their formed unit, often fill shortages or provide specialized knowledge or skill sets. This article examined the effect of deploying as an IA on mental health outcomes and unit cohesion. A U.K. military cohort study was used to compare IAs (n = 1352) with personnel who had deployed with a formed unit (n = 2980). Differences between the groups in questionnaire assessed symptoms of post-traumatic stress disorder (PTSD Checklist-Civilian Version), common mental disorders (General Health Questionnaire-12) and alcohol misuse (Alcohol Use Disorders Identification Test) were examined with logistic and negative-binomial regression analyses. There was no difference between IAs and those who deployed with a formed unit in level of unit cohesion, symptoms of post-traumatic stress disorder or common mental disorder. Deployment as an IA was associated with less alcohol misuse (Odds Ratio 0.77, 95% Confidence Interval 0.63-0.94). IAs appeared able to integrate with the group they deployed with as levels of unit cohesion were similar to personnel who deployed with a formed unit. IAs were also at a lower risk of alcohol misuse compared to personnel who deployed with a formed unit.

Long-term CD4+ lymphocyte response following HAART initiation in a U.S. Military prospective cohort

BackgroundAmong HIV-infected persons initiating highly active antiretroviral therapy (HAART), early CD4+ lymphocyte count increases are well described. However, whether CD4+ levels continue to increase or plateau after 4-6 years is controversial.MethodsTo address this question and identify other determinants of CD4+ response, we analyzed data for 1,846 persons from a prospective HIV military cohort study who initiated HAART, who had post-HAART CD4+ measurements, and for whom HIV seroconversion (SC) date was estimated.ResultsCD4+ count at HAART initiation was ≤ 200 cells/mm3 for 23%, 201-349 for 31%, 350-499 for 27%, and ≥500 for 19%. The first 6 months post-HAART, the greatest CD4+ increases (93-151 cells) occurred, with lesser increases (22-36 cells/year) through the first four years. Although CD4+ changes for the entire cohort were relatively flat thereafter, HIV viral load (VL) suppressors showed continued increases of 12-16 cells/year. In multivariate analysis adjusting for baseline CD4+ and post-HAART time interval, CD4+ responses were poorer in those with: longer time from HIV SC to HAART start, lower pre-HAART CD4+ nadir, higher pre-HAART VL, and clinical AIDS before HAART (P < 0.05).ConclusionsSmall but positive long-term increases in CD4+ count in virally suppressed patients were observed. CD4+ response to HAART is influenced by multiple factors including duration of preceding HIV infection, and optimized if treatment is started with virally suppressive therapy as early as possible.