Introduction The prevalence of smokeless tobacco use among U.S. active duty service members has been much higher than in the U.S. general population. The association between deployment and smokeless tobacco use has not been well studied. We investigated the association between deployment and smokeless tobacco use among U.S. active duty service members. We also evaluated the modification effects from other factors related to smokeless tobacco use on the deployment-smokeless tobacco use association. Materials and Methods Eligible active duty service members stationed at two military installations (Fort Bragg, NC, USA and Lackland Air Force Base, TX, USA) were recruited from July 2015 to May 2016. Each participant completed a self-administered questionnaire. Multivariable logistic regression was used to assess the association between deployment and smokeless tobacco use and estimated odds ratio (OR) and 95% confidence interval (CI). Stratified analysis was performed to evaluate modification effects from other commonly known factors related to smokeless tobacco use in military, specifically, cigarette smoking status, use among family members (family history of use), perception of harm, and use among military peers. Results Out of 2,465 study participants who completed the questionnaire, 548 were smokeless tobacco users. Service members who had been deployed to a combat zone had 1.39 fold (95% CI = 1.03-1.87) increased odds of using smokeless tobacco than those who never deployed to a combat zone. The odds of smokeless tobacco use among those who had been deployed once, twice, three times and four or more times to a combat zone were 1.27 (95% CI = 0.91-1.78), 1.30 (95% CI = 0.85-1.99), 2.49 (95% CI = 1.45-4.28), and 2.88 (95% CI = 1.71-4.86), respectively, with a significant dose-response trend (p for trend <0.0001). Further, subjects who served in combat units during deployment exhibited more than two-fold increased odds of use as compared with those who had never been deployed (OR = 2.03, 95% CI = 1.41-2.93). In stratified analysis, the association between deployment and smokeless tobacco use was only present among subjects who never smoked cigarettes, those without family history of smokeless tobacco use, and those who had low perception of harm of use. Conclusions Military deployment was associated with smokeless tobacco use among active service members. However, the influence of military deployment on smokeless tobacco use was not equally strong on all service members. Subjects who never smoked cigarettes, who had no family history of use and who had low perception of harm were the most susceptible subgroups to deployment-related smokeless tobacco use. This study has implications to identify high-risk subgroups to reduce smokeless tobacco use in the U.S. military.
- Smokeless tobacco
- U.S. Military