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

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.

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.

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.

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.