Nevin RL, Means GE. Pain and discomfort in deployed helicopter aviators wearing body armor. Aviat Space Environ Med 2009; 80:807–10. Background: In early 2007, U.S. Army helicopter aviators deployed to Afghanistan complained of increased pain frequency during flight. The aviators attributed this pain to body armor, which had not been worn prior to deployment. This study was conducted to investigate these complaints. Methods: A retrospective study of pain frequency among 68 deployed helicopter aviators was performed using self-reported categorical pain ratings and flight times abstracted from a safety questionnaire. To assess the association of substantial increases in flight time on reported pain frequency, study subjects were divided into a group reporting a decrease or increase of 1 h or less in average daily flight hours during deployment as compared to predeployment (level flight hours, LFH) and a group reporting an increase of greater than 1 h in average daily flight hours (increased flight hours, IFH). Results: A significantly higher proportion of aviators in the IFH group reported an increase in pain frequency as compared to LFH (81.5% vs. 61.1%, respectively). The relative risk (RR) of increased pain frequency associated with IFH was greatest in the lower back (RR = 1.80), legs (RR = 2.60), arms (RR = 9.11), and the groin (RR = 12.1). Discussion: This study provides preliminary evidence that complaints of increased pain frequency during deployment were associated with substantial increases in flight times. Further study is warranted to investigate and confirm the underlying causes of this pain.