Health and Wellbeing Cohort Study of Serving and Ex-Serving UK Armed Forces Personnel: Phase 4 Protocol

Introduction This is the fourth phase of a longitudinal cohort study (2022-2023) to investigate the health and wellbeing of UK serving (Regulars and Reservists) and ex-serving personnel (veterans) who served during the era of the Iraq and Afghanistan conflicts. The cohort study was established in 2003 and has collected data over three previous phases including Phase 1 (2004-2006), Phase 2 (2007-2009) and Phase 3 (2014-2016). Methods and analysis Participants are eligible to take part if they completed the King’s Centre for Military Health Research (KCMHR) Health and Wellbeing Cohort Study at Phase 3 (2014-2016) and consented to be recontacted. Participants meeting these criteria will be recruited through email, post, and text message to complete an online or paper questionnaire. The study provides a fourth phase of quantitative longitudinal data on this cohort. Data are being collected between January 2022 and September 2023. Health and wellbeing measures used in Phase 4 include measures used in previous phases that assess common mental disorders (CMD), post-traumatic stress disorder (PTSD) and alcohol misuse. Other areas of interest assess multiple symptom illness, employment, help-seeking, and family relationships. New topics include the impact of the British withdrawal from Afghanistan in 2021, Complex-PTSD (C-PTSD), illicit drug use, gambling, and loneliness. The main analyses will compare mental health status according to deployment experiences and serving status (serving or ex-service) reporting prevalences with 95% Confidence Intervals (CI), and Odds Ratios (ORs) with 95% CI. Analyses will describe the effect size between groups deployed to Iraq and/or Afghanistan or not deployed, and those who are currently in service versus ex-service personnel respectively. Multivariable logistic and multiple linear regression analyses will be conducted to assess various health and wellbeing outcomes and associations with risk and protective factors, adjusting for potential confounders. Ethics and dissemination Ethical approval has been granted by the Ministry of Defence Research Ethics Committee (Ref: 2061/MODREC/21). Participants are provided with information and agree to a series of consent statements before taking part. Data are kept on secure servers and in locked cabinets/offices, with access to personally identifiable information limited. Findings will be disseminated to UK Armed Forces stakeholders and international research institutions through stakeholder meetings, project reports and scientific publications. Strengths and limitations of this study Strengths of this study include the original cohort recruitment from a random, representative sample of UK service personnel. Strengths also include recruitment from a cohort where underlying characteristics are known and longitudinal data are held on their health and wellbeing. The study has maintained validated and harmonised health and wellbeing measures across phases, whilst including new areas relevant to the cohort’s current experiences. This study will provide continued longitudinal data on this Armed Forces cohort. Study limitations include recruitment from a specific cohort; hence the study cannot comment on older era cohorts or those who joined the Armed Forces more recently.