An evaluation of the effect of military service on mortality: quantifying the healthy soldier effect

Abstract

Purpose: The healthy soldier effect denotes the proposition that military populations are likely to be healthier than other populations. A systematic review was conducted which aimed to quantify the magnitude of the healthy soldier effect.

Methods: Studies containing mortality rates of military personnel were identified from multiple electronic databases. Studies were included in the meta-analyses if they reported all-cause, cancer, or external-cause mortality in a military population and compared the rates to the general population. Fifty-nine studies were initially identified and 12 were included in the meta-analyses.

Results: The overall meta-standardized mortality ratios (SMRs) for all-cause mortality for deployed veterans was 0.76 (95% confidence interval [CI]: 0.65-0.89) and 0.73 (95% CI: 0.56-1.97) for non-deployed veterans based on a mean follow-up of 7.0 and 2.4 years, respectively; for cancer mortality, the SMRs were 0.78 (95% CI: 0.63-0.98) for deployed veterans and 0.75 (95% CI: 0.50-1.14) for non-deployed veterans based on 6.7 and 3.1 years follow-up, respectively; for external-cause mortality, the SMRs were 0.90 (95% CI: 0.72-1.13) for deployed veterans and 0.80 (95% CI: 0.63-1.01) for non-deployed veterans based on 4.8 and 2.0 years follow-up, respectively.

Conclusion: Military personnel do display a healthy soldier effect that decreases their risk of mortality compared to the general population. The overall healthy soldier effect estimated ranges from 10% to 25%, depending on the cause of death studied and the period of follow-up.