Association of deployment with maintenance of healthy weight among active duty service members in the Millennium Cohort Study.

Objective: Understanding body size in relation to deployment readiness can inform Department of Defense fitness policies. This study examined longitudinal associations between deployment and changes in body mass index (BMI) among active duty service members.

Methods: Service branch-specific changes in BMI post-deployment were examined using logistic regression models among active duty Millennium Cohort Study participants without obesity at baseline ( = 22,995). BMI was categorized using self-reported height and weight as healthy weight (18.5-24.9 kg/m), overweight (25.0-29.9 kg/m), and obese (≥30 kg/m). Number of deployments between baseline and follow-up and initial deployment lengths (in months, using service branch-specific deployment times) were examined.

Results: Among the pooled population and specifically Army and Marine Corps service members without obesity, those with longer deployments were significantly less likely to maintain a non-obese BMI than those deploying for shorter lengths. Each additional deployment increased the likelihood of maintaining a non-obese BMI post-deployment for personnel in the Army, Marine Corps, and within the pooled population.

Conclusions: Multiple deployments may support healthy weight maintenance; longer deployments may adversely impact weight maintenance. Future research should determine modifiable behaviors related to weight gain post-deployment to inform fitness policies designed to optimize service member readiness and deployability.