Risk factors, comorbidity and social impairment of ICD-11 PTSD and complex PTSD in Danish treatment-seeking military veterans.

PURPOSE: While a number of studies have investigated risk factors and comorbidities of ICD-11 post-traumatic stress disorder (PTSD) and complex PTSD (CPTSD) in various trauma exposed samples, few studies have been conducted in military samples. Existing studies with military samples have included rather small samples. The aim of the present study was to identify risk factors and comorbidities of ICD-11 PTSD and CPTSD in a large sample of previously deployed, treatment-seeking soldiers and veterans. METHODS: Previously deployed, treatment-seeking Danish soldiers and veterans (N = 599), recruited from the Military Psychology Department of the Danish Defense, completed the International Trauma Questionnaire (ITQ), as well as questionnaires of common mental health difficulties, trauma exposure, functioning and demographics. Multivariate multinomial logistic regression analysis explored differences in self-reported exposure to adversity and health outcomes between those meeting ICD-11 criteria for probable PTSD, CPTSD and no trauma disorder. RESULTS: A total of 13.0% met probable ICD-11 criteria for PTSD and 31.4% for CPTSD. Risk factors for CPTSD (compared to those with no trauma disorder) included exposure to warfare or combat, longer duration since the traumatic event and being single. Those with CPTSD were more likely than those with PTSD or no trauma disorder to endorse symptoms of depression, anxiety, stress, use of psychotropic medication, and suicide attempts. CONCLUSION: CPTSD is a more common and debilitating condition compared to PTSD in treatment-seeking soldiers and veterans. Further research should focus on testing existing and novel interventions for CPTSD in the military.

Applicability of an Automated Model and Parameter Selection in the Prediction of Screening-Level PTSD in Danish Soldiers Following Deployment: Development Study of Transferable Predictive Models Using Automated Machine Learning.

BACKGROUND: Posttraumatic stress disorder (PTSD) is a relatively common consequence of deployment to war zones. Early postdeployment screening with the aim of identifying those at risk for PTSD in the years following deployment will help deliver interventions to those in need but have so far proved unsuccessful. OBJECTIVE: This study aimed to test the applicability of automated model selection and the ability of automated machine learning prediction models to transfer across cohorts and predict screening-level PTSD 2.5 years and 6.5 years after deployment. METHODS: Automated machine learning was applied to data routinely collected 6-8 months after return from deployment from 3 different cohorts of Danish soldiers deployed to Afghanistan in 2009 (cohort 1, N=287 or N=261 depending on the timing of the outcome assessment), 2010 (cohort 2, N=352), and 2013 (cohort 3, N=232). RESULTS: Models transferred well between cohorts. For screening-level PTSD 2.5 and 6.5 years after deployment, random forest models provided the highest accuracy as measured by area under the receiver operating characteristic curve (AUC): 2.5 years, AUC=0.77, 95% CI 0.71-0.83; 6.5 years, AUC=0.78, 95% CI 0.73-0.83. Linear models performed equally well. Military rank, hyperarousal symptoms, and total level of PTSD symptoms were highly predictive. CONCLUSIONS: Automated machine learning provided validated models that can be readily implemented in future deployment cohorts in the Danish Defense with the aim of targeting postdeployment support interventions to those at highest risk for developing PTSD, provided the cohorts are deployed on similar missions.

Low-level cognitive ability in young adulthood and other risk factors of depression in an observational cohort study among deployed Danish soldiers.

PURPOSE: Evidence exists of an association between pre-morbid lower cognitive ability and higher risk of hospitalization for depressive disorder in civilian cohorts. The purpose of this study was to examine the relationship of cognitive ability at conscription with post-deployment depression and the influence of (1) baseline factors: age, gender, and pre-deployment educational level, (2) deployment-related factors: e.g., war-zone stress and social support, and (3) co-morbid PTSD. METHODS: An observational cohort study linking conscription board registry data with post-deployment self-report data. The study population consisted of Danish Army military personnel deployed to different war zones from 1997 to 2015. The association between cognitive ability at conscription and post-deployment depression was analyzed using repeated-measure logistic regression models. RESULTS: Study population totaled 9716 with a total of 13,371 deployments. Low-level cognitive ability at conscription was found to be weakly associated with post-deployment probable depression after adjustment for more important risk factors like gender, education, and deployment-related factors [odds ratio (OR) 0.93, 95% confidence interval (CI) 0.88-0.99]. The co-occurrence rate with PTSD was nearly 60%. When adding co-morbid PTSD as an independent variable, the association between cognitive ability and probable depression became insignificant, OR 0.95, CI 0.89-1.02. CONCLUSIONS: Low cognitive ability at conscription is a risk factor for depression among returning military personnel, but unimportant compared to gender, education, and deployment-related factors. Part of this effect may be related to co-morbid PTSD. Use of cognitive ability score as an isolated selection tool cannot be recommended because of low predictive performance.

Increased Postdeployment Use of Medication for Common Mental Disorders in Danish Gulf War Veterans.

BACKGROUND: Gulf War veterans (GWVs) have an elevated risk of reporting symptoms of mental disorders as compared with nondeployed military controls. A difficulty in the Gulf War health research is that most health outcomes are self-reported; therefore, it is highly relevant to study objective outcomes in this line of research. The Danish National Prescription Registry provides an opportunity to use the prescription of drugs as an objective evaluation of the impact of mental health disorders at the individual level. In this study, we investigated the prescription of drugs and postdeployment hospitalizations for mental disorders among GWVs compared with a control population of nonveterans (NVs). METHODS: A prospective registry study including a cohort of 721 GWVs and a control cohort of 3,629 NVs. Main outcome measures were incidence of (1) use of antidepressants, (2) use of anxiolytic/hypnotic medication, and (3) number of postdeployment psychiatric contacts. The association between outcomes and GWVs status was studied by using time-to-event analysis. The index date was the return date from the last deployment to the Gulf. The follow-up period was the time from index date until December 31, 2014. FINDINGS: GWVs had an elevated average risk over time for use of both types of medication compared with NV. For use of antidepressants the average hazard rate (HR) was 2.56, with 95% confidence interval (CI) = 2.04-3.21 (p < 0.0001); for use of anxiolytic/hypnotic medication the corresponding results were HR = 1.78, CI = 1.37-2.31 (p < 0.0001). The interaction with time was statistically significant with HR increasing with time for both outcomes. Incident use of antidepressants in GWVs after 10 years was two times higher than among NV, after 20 years it was nearly four times higher than among NV. Incident use of anxiolytic/hypnotic medication was one and a half that of NV after 10 years, but nearly three times that of NV after 20 years. There was no difference in rate of postdeployment psychiatric contacts. DISCUSSION/IMPACT/RECOMMENDATIONS: The findings of increased use of antidepressants and anxiolytic or hypnotic medicine among GWVs compared with NVs were rather surprising since we recently, by using the same study population, found that deployment to the Persian Gulf was not associated with increased sickness absence or reduced labor market attachment. However, our results indicate that the mental health of the Danish GWVs is worse than in NV, and that this unfavorable difference increased with time. A possible explanation is that veterans have a high motivation for being in work, and that the deployment-related mental problems they may have acquired do not impair their ability to work, when treated properly. Furthermore, registry-based research in GWVs could include other outcomes, e.g., the use of pain medication, and other military comparison groups, e.g., veterans deployed to other areas than the Persian Gulf in addition to NV. The method of surveillance of military personnel with register data pertinent to health and monitoring outcomes compared with suitable control populations is highly recommended as a tool in the prevention of deployment-related health problems.

Danish Gulf War Veterans Revisited: No Evidence of Increased Sickness Absence or Reduced Labor Market Outcome After Deployment to the Persian Gulf.

OBJECTIVE: To examine the assumption that postdeployment incidence of sickness and other absence from work are higher among Gulf War Veterans compared with nonveterans. METHODS: A prospective registry study including a cohort of 721 Danish Gulf War Veterans and a control cohort of 3,629 nonveterans selected from the general Danish population. Outcome measures were up to 23 years postdeployment incidence of (1) long-term sickness absence and (2) long-term all types of absence from work. Long term with regard to sickness and other absence was defined as exceeding 8 weeks. The association between outcomes and information on deployment history was studied using time-to-event analysis. The index date was the return date from the last deployment to the Gulf. The follow-up period was the time from index date until April 27, 2014. RESULTS: As the main finding, no difference was found between veterans and nonveterans in the incidence rate of long-term sickness absence. After an initial short period (3 months) with elevated incidence rate of long-term absence from work among veterans, there was no difference between the cohorts. CONCLUSION: Among Danish Gulf War Veterans, no postdeployment increased risk of long-term sickness absence or long-term absence from work was found as compared with nonveterans.

Deployment-related risk factors of low back pain: a study among danish soldiers deployed to Iraq.

Where much is known about the consequences of spinal and low back pain (LBP) during military deployments, there is lesser knowledge of risk factors for LBP among the deployed forces. The objective of this study was to identify deployment-related exposures associated with LBP. The study was a questionnaire-based cohort study among 1,931 Danish soldiers deployed to Iraq. Of the 680 respondents, 175 (26%) reported LBP. The population of respondents was adjusted for potential nonresponse bias. The associations between LBP and explanatory variables were analyzed using ordinal logistic regression models. Older age (p = 0.016), support from leaders (odds ratio [OR] = 1.69, p = 0.019), psychological stress (OR = 1.71, p = 0.009), awkward working positions (OR = 1.98, p = 0.001), and working in depots or storehouses (OR = 2.60, p = 0.041) were found to be associated with LBP after adjustment of all other variables. Combat and exposure to work, sport, or traffic accidents were not associated with LBP in this study, which was attributed to the characteristics of the actual mission. Preventive measures should include predeployment preparation of leaders to cope with LBP and other musculoskeletal trouble among their subordinates and involve medical personnel, especially deployed physiotherapists, by giving advice to soldiers of different military occupational specialties on how to optimize ergonomics at work.

Danish soldiers in Iraq: perceived exposures, psychological distress, and reporting of physical symptoms.

Using data from an occupational medical health surveillance program, we studied the associations between mental stressors and social support and the two outcome measures postdeployment psychological distress and multiple physical symptoms among Danish soldiers deployed to Iraq. The study was cross-sectional and questionnaire-based with soldiers returning from the mission as the target group. Witnessing atrocities, fear of being physically harmed, feeling of insecurity, feeling of meaninglessness, and having been in touch with prisoners were associated with both outcome measures. In conclusion, our findings support the assumption that other factors than combat exposure-psychosocial and cultural-are of importance in increasing psychological distress among soldiers deployed to Iraq. Additionally, we have shown that the reporting of multiple physical symptoms among the deployed soldiers is closely related to increased psychological discomfort and certain mental stressors.

Musculoskeletal disorders in main battle tank personnel.

PURPOSE: To compare the prevalence of musculoskeletal disorders of personnel in the main battle tank (MBT) units in the Danish army with those of personnel in other types of army units, and to investigate associations between job function in the tank, military rank, and musculoskeletal problems. METHOD: An epidemiologic cross-sectional questionnaire-based examination of an exposed group (MBT personnel) and a reference group (army personnel from other units than MBT units) was conducted. Outcome measures were 1-year prevalence of pain in the anatomical locations of neck, shoulder, low back, knee, and ankle. RESULTS AND CONCLUSIONS: There were only 4 women in the MBT group; as a consequence, female personnel were excluded from the study. The participation rate was 58.0% (n = 184) in the MBT group and 56.3% (n = 333) in the reference group. The pattern of musculoskeletal disorders among personnel in the main battle tank units of the Danish army was not significantly different from that in other types of units (infantry, signal, combat service support, engineers, and artillery). Working as a gunner less than 2 years increased the risk of reporting neck pain (p = 0.011) and working as a loader increased the risk of reporting shoulder pain (p = 0.017).

[Adverse reactions to anthrax vaccination in Danish military personnel deployed to Iraq]. / Bivirkninger ved anthraxvaccination i forbindelse med udsendelse af danske soldater til Irak.

INTRODUCTION: On Denmark's decision to join the war in Iraq, it was decided to immunise all personnel to be deployed there with anthrax vaccine. This paper describes the types and frequency of adverse reactions to the vaccine. MATERIALS AND METHODS: Between March 2003 and February 2004, 1,899 immunisations against anthrax in 755 personnel were registered at the health care facilities of the Danish Defence. RESULTS: No serious or life-threatening adverse reactions were reported. The data showed a statistically significant decrease in adverse reactions between the four immunisation series. For males, adverse reactions after the second immunisation depended on possible adverse reactions to the first immunisation. In females, this correlation was not found. No differences in the frequency of adverse reactions between males and females were found. DISCUSSION: None of the vaccinated persons suffered serious or life-threatening adverse reactions. Compared to other studies on self-reported adverse reactions, the overall frequency was low. The data showed a statistically significant decrease in adverse reactions between the four immunisation series. This has been described in comparable studies. The correlation between adverse reactions in the second immunisation being dependent on adverse reactions to the first immunisation has been partly confirmed by other studies. No differences between the sexes were found, probably because only a few females were included in the study. In case of a significant level of threat concerning biological weapons, immunisation against anthrax is considered appropriate.