Suicide, violent crime, divorce and mortality in deployed military veterans

It has long been known that individuals deployed to war and conflict zones might suffer from mental health problems after returning home. This thesis investigated suicide, violent crime, divorce and marriage in deployed Swedish military veterans (study I-III), as well as all-cause and cause-specific mortality in Nordic military veterans (study IV), deployed between 1990 and 2013. The analyses were based on a linkage of the Swedish Armed Forces’ register of deployed veterans and nationwide registers. To limit the impact of “the healthy soldier effect”, that is the tendency of veterans to be healthier than the general population due to military selection criteria, a tightly matched comparison group was created using individual level information on mental and physical health in addition to age- and sex-matched comparators. In Study IV, Danish, Finnish and Norwegian deployed veterans were also analysed.

In Study I, we found that the risk of death by suicide after return from deployment in more than 20,000 Swedish military veterans who had been deployed between 1990 and 2013 was similar t0 the thightly matched non-deployed comparators (1.5 versus 1.6 per 10,000 person-years; hazard ratio [HR] 1.07; 95%CI 0.75-1.52). In Study II, we found that Swedish military veterans who had deployed to Afghanistan sometime between 2002 and 2013 were more likely to divorce (277 versus 178 per 10,000) person-years; HR 1.56, 95%CI 1.27-1.91) (399 versus 444 per 10,000 person-years; HR 0.89, 95%CI 0.83-0.96) after return from deployment compared with the tightly matched non-deployed comparators. In Study III, we found that Swedish military veterans who had deployed to Afghanistan had a similar violent crime conviction rate after return from deployment as the tightly matched comparators (12 versus 9 per 10,000 person-years; HR 1.36, 95%CI 0.88-2.10). In Study IV, we found lower all-cause mortality in military veterans from Sweden, Denmark, Finland and Norway deployed between 1990 and 2010 compared with the general population. Lower risk was also observed for death from external causes, suicide, cardiovascular disease and neoplasms. There was, however, no difference in risk of fatal traffic/transport accidents between deployed military veterans and the general population.

In summary, this thesis found no association between military deployment and death by suicide or violent crime conviction in Swedish veterans versus non-deployed comparators who were similar with respect to several factors. However, higher probability of divorce and lower probability of marriage after return from deployment were observed among the veterans. In terms of mortality outcomes, Nordic military veterans were similar and had consistently lower, or similar, risk of death after return from deployment compared with the general population.

List of scientific papers

I. Pethrus CM, Johansson K, Neovius K, Reutfors J, Sundstrom J, Neovius M. Suicide and all-cause mortality in Swedish deployed military veterans: a population-based cohort study. BMJ Open. 2017;7(9):e014034.
https://doi.org/10.1136/bmjopen-2016-014034

II. Pethrus CM, Reutfors J, Johansson K, Neovius K, Söderling J, Neovius M, Bruze G. Marriage and divorce after military deployment to Afghanistan: a matched cohort study from Sweden. PLoS One. 2019;14(2):e0207981.
https://doi.org/10.1371/journal.pone.0207981

III. Pethrus CM, Frisell T, Reutfors J, Johansson K, Neovius K, Söderling J, Bruze G, Neovius M. Violent crime among Swedish military veterans after deployment to Afghanistan: a population-based matched cohort study. [Accepted]
https://doi.org/10.1093/ije/dyz084

IV. Pethrus CM, Vedtofte MS, Neovius K, Borud EK, Neovius M. All-cause and cause-specific mortality among Nordic military veterans following international deployment: a meta-analysis. [Manuscript]